Direct View Television
Contents
1. If this voltage should rise above 6 2 volts D626 begins to conduct When its conduction allows Q622 Protect to turn ON over voltage protection is employed Q622 Protect turns ON and grounds Q621 G which stops the converter from switching D699 is also used for OVP The signal from T621 4 is rectified by D698 This creates a negative voltage across C699 If this negative voltage becomes great enough D699 conducts and the Q621 G voltage is brought lower Secondary Output The power coupled through T621 SRT places a voltage on T621 9 that when rectified and filtered by D628 and C637 is 7 2 volts This voltage is constant due to the regulation circuit on the primary side of T621 SRT This 7 2 volts is applied to Q646 E for backup during the start of regula tion by the regular power supply It is also applied to 622 5 Volt Regulator which regulates its output to 5 volts This 5 volts is sent to CN641 10 which connects to the A board and powers the Tuning Micon and other circuits It is also applied to RY600 Power Relay Checking Q621 Testing a MOSFET device is simple The leads show infinite resistance to each other except for drain to source in one direction because of the presence of a protection diode To prove the device is functional 1 Connect the negative lead of the ohmmeter to the SOURCE lead 2 Touch the ohmmeter positive lead to the gate to pre charge it 3 Connect the ohmmeter positive lead to the DRAIN If t2. In the case of intermittent problems you can check the failure status his tory by pressing the Display 5 Vol and Power buttons You will see a menu that indicates how many times each item has failed The failure information is stored in the EEPROM MA MB BOARD VERTICAL OUTPUT PROTECT STANDBY STANDBY STANDBY 7 5 BV SUPPLY REG IC1001 SYSCON YCJ STANDBY TIMER LED HLDWN AUDIO SWITCHING SUPPLY 22937 LV SUPPLY BOARD POWER SUPPLY AND SELF DIAGNOSTICS BLOCK 10 Power ON Degaussing Overview The Power ON Degaussing circuit shown also includes the AC input and Reset circuits When the unit is first plugged in power is applied to the line filter to the Standby Supply The Standby Supply powers the System Control IC EEPROM remote sensor and reset circuits After reset if a Power ON command is received the System control IC outputs voltages to turn ON the Power and Degauss relays When operating correctly the following can be observed in sequence the power relay clicks one sec ond later the degauss relay clicks the hum of the DGC is heard for about two seconds the degauss relay clicks again two seconds later and then finally a picture is displayed This entire sequence occurs within the first 5 10 seconds the unit is powered ON AC Input The AC is input to the A board through CN602 The Hi side of the AC line passes through T602 1 and 2 and R605 and R606 These resisto
3. Once 0621 Converter turns OFF all polarities are reversed This sal of polarity helps speed up turn OFF of Q621 D623 along with C631 and R640 form a snubber network voltage clamp This network clamps excessive voltage overshoot caused by the collapsing magnetic field of T621 SRT and returns the excessive voltage to C629 When the field collapses fully current begins to flow through T621 1 and 3 The waveforms below show what will be seen at Q621 H gt M 18 Q621 D 50 mv 10 us Q621 G 1 V 10 us an fre Es pore Ede 7512 9 Regulation 0621 5 1 10 us Changing the frequency of the switching regulates the output voltage at the secondary winding comprised of T621 8 and 9 Taking a sample volt age from T621 4 and applying it to rectifiers D624 and D625 does this As this voltage rises and falls the rectified voltage is applied to Q622 B through R634 When Q622 begins to conduct it lowers the voltage at Q621 G and changes the switching frequency The changing frequency will change the amount of voltage coupled to the secondary winding consisting of T621 8 and 9 If the load on the second ary output increases the frequency of switching will decrea
4. These pulses are one horizontal line in duration and they occur during every field They are output so they occur on consecutive lines with red first followed by green and blue They are buffered by Q1315 Q1316 and Q1317 and applied to 1303 CN1303 is connected to CN705 on the CB board The cable connecting the two boards is hardwired and cannot be unplugged from either end The RGB signals that are applied to the CB board are input directly into pins 1 2 3 of IC702 CRT Drive 702 amplifies and inverts these signals and applies them to the cathode of the tube for their respective colors If the tube is biased correctly three lines will be produced in the overscan area of the picture tube 1 702 5 IK outputs a voltage signal that represents the amount of total current being drawn by the tube cathodes Since each color is outputting a pulse for one H line in every field we would see a waveform like that shown below at 01350 or 01331 Base It is very hard to see this wave form at other places so it is recommended that you only check IK return here Q1331 B 1v 5ms 33 Place your scope in delayed mode and highlight the area that appears to be one pulse Expand it and you will see that there are three distinct pulses one for each color Your scope should be set to 5ms per division Some scopes that have less than 100MHz bandwidth may have trouble triggering o
5. 4 24 00 Audio without Board Overview The BA 5 chassis can contain one of two types of audio circuits depend ing on the model One type uses the K board and the other does not Screen size is not a factor in the use of a board This section discusses models that do not use the K board There are also two different audio amplifiers that can be used by the BA 5 chassis The one shown here is used in all models that output 5Wx2 or less The other audio output which will be shown in the Audio With K Board section is used for models with at least 10Wx2 power output Switching Models without the board use separate audio switches 405 and 1 406 for each channel The left channel is switched by 405 and the right channel is switched by IC406 These switches each have three audio inputs and two control line inputs The control lines are the same ones used in video switching on 24 and under models The following table shows the state of the control lines for the input selected Input 1 405 406 1 1 405 406 52 0 Volts 0 Volts Video 1 3 3 Volts 0 Volts Video 2 0 Volts 3 3 Volts Whichever input is chosen is output from its respective IC at pin 7 Audio Amp The output from the switching circuit is applied to a RC network on each channel After passing through the RC network the signals enter 1 401 Audio Amp 1 401 Audio Out amplifies the input signals and outputs them as a differenti
6. AC input voltages IC601 1 IC601 3 12601 4 Switching B 40VAC 87 VDC 160Vpp 12VDC 51 VDC 60VAC 98 VDC 200Vpp 12 83 79 VDC 80VAC 1 11 230Vpp 13 2VDC 106 VDC 100VAC 1 21 260 Vpp 13 5 VDC 134 VDC 120VAC 1 22 280Vpp 13 9VDC 163 VDC You should also note that under the above conditions the 135 volt output L603 remained at 136 volts throughout The signal seen at 603 3 started as sine waves clipped at the negative peaks and gradually came to look more like a normal sine wave as the input voltage was increased The frequency of this signal ranged from 236 kHz at 40 VAC to 320 kHz at 120 VAC 601 1 1v T603 7 10v 5us 601 2 1v 5us 12601 STR F6624 6654 A BOARD CONVERTER D GND S VIN OCP FB R637 R662 R660 AAA AM R632 2 0610 1 me C647 C644 TO IN RUSH CURRENT R621 LIMIT PROTECT ONLY FOUND IN 24 AND ABOVE MODELS SEE RUSH CURRENT PROTECTION SWITCHING POWER SUPPLY 20 123 7 VDC FROM 135 ERROR FROM 60
7. Parental Control Video Label XDS Closed Captioning Multi Language Display Auto Channel Programming Favorite Channel or Customer Tilt Control Favorite Preview The KV 20FV12 KV 24FV12 and all 27 and above models have the Preset Program Palette feature KV 27FV16 KV 27FS16 and the KV 32FS16 contain 2 tuner PIP This includes the Freeze Memo feature Input Output S Video Y Pb Pr Composite Fix Var Out KV 20FS12 1 1 KV 20FV12 1 1 Yes KV 24FV12 EE 1 1 KV 27FS12 2 1 Yes KV 27FV16 2 1 Yes KV 32FS12 2 1 Yes KV 32FS16 2 1 Rear Front e KV 27FV16 contains a Monitor Out jack Feature Glossary Auto Mute Mutes the audio output when the tuner receives no signal This keeps the loud volume from occurring due to static Auto SAP If activated Auto SAP automatically switches to the SAP audio if SAP audio is present BBE Audio Enhancement Shifts the phase of the audio signal to im prove TV sound Dynamic Acoustic Chamber DAC A speaker enclosure that uses the cabinet to improve sound quality SRS 3D A digital signal processing algorithm that simulates surround sound using only two speakers Dynamic Focus Automatically adjusts the focus to improve focus certain parts of the screen Magnetic Quadra pole Controls the electron beam magnetically to enhance picture resolution Trinitone Color Temperature Adjustment Enables the user to adjust
8. in previous chassis In those sets it is the HP H OFF line In these models during an H protect condition pin 18 would be grounded and HD at pin 19 would be halted The H protect circuit does not operate in this manner the BA 5 chassis but should IC1301 18 be grounded it would cause HD to cease 1C1301 18 HP should be checked for a short to ground in the event that the YCJ is not outputting HD 27 If IC1301 YCJ is outputting HD the next step is to see if this signal is present at the base of Q501 H Drive If the signal looks good at Q501 B then the base of Q502 H Out could be unloaded by unsoldering 1 side of R504 This will determine if Q501 can output a signal with its load T501 connected The following waveform should be seen at R504 with Q502 B disconnected R504 with Q502 B unsoldered 5V 20US Reconnect R504 if this signal is present In order to be certain that T501 is capable of handling a load you should unsolder L510 and R648 not shown These components pass the 135 volts through to T505 FBT These components were chosen because they are easier to unsolder then more evident components which are soldered to the board where there are eyelets Note Before doing this ensure that SW501 H Cen tering Switch is in the center position Otherwise damage will occur to the set The signal below should be present at Q502 B
9. larger screen size models use the MA board in place of the MB board This allows for more inputs including component video and a 2 tuner for PIP There are also connections for the additional boards used for PIP and 3D Comb Filter Inputs and Monitor Out Larger BA 5 chassis sets can have up to six inputs Video 1 and 2 inputs can be composite and S Video Video 3 input can be composite only Video 4 is component only There are also inputs for two tuners One main is located on the A board and one sub is located on the MA board The signals are input by the jacks if it is a Video input and from the tuners if it is broadcast video All of these signals will be output from different connectors on the A board to connectors on the MA board with the ex ception of the sub tuner which is already located on the MA board All signals input to the The contains switching circuits for component composite and Video The selected composite video or signals are output IC301 17 Mon Out If the selected signal is a composite video signal it is sent to Q304 and Q306 and then back to the A board for Monitor Out It is also sent to the B Board or to IC302 Digital Comb Filter In the case of an S Video the Y Q304 and Q306 combine their signal with the C signal from IC301 19 with the Y from 1 301 17 The output from the transistors is a composite sig nal that will be sent to the A board for the Monitor Out jack J204 If the compo
10. remote control 1 1001 8 Relay goes LOW This LOW is sent to the A board via pin 7 of CN1004 and CN2002 It is then applied to Q604 B turning Q604 OFF When Q604 is OFF the Standby 7 5 volts is applied to the base of Q607 through R661 and R630 This turns Q607 ON and allows current to flow through RY602 which causes the contacts in RY602 to close When the contacts close AC is applied to D605 Bridge Recti fier This allows the Switching Supply to begin to operate When the switching supply is operating the set should be ON Degaussing About one second after the Power Relay is closed the Degauss Relay is closed This occurs because 1 1001 13 outputs a HIGH which is sent to the A board via pin 6 of CN1004 and CN2002 Itis then applied to Q609 B This turns Q609 ON allowing current to flow through RY601 Degauss Relay This closes the contacts of RY601 and allows current to flow through THP601 and the DGC This action is accompanied by the sound of the DGC humming Current flows through the DGC until THP601 becomes warm 601 is a thermistor and its resistance increases rapidly as its temperature increases Its resistance will increase so much that after about two three seconds current flowing through the DGC will be greatly reduced After about five seconds 1001 13 DGC goes LOW and the Degauss Relay is turned OFF Shutdown The outputs from the Latch and the Standby 7 5 volt over voltage protec tion circuit are connected to
11. repeats 15 4 Normal 3 then fourth No Yes 4 Yes Set ON and 502 Out R549 for shutdown symptom repeats 22 135 OCP and H Protect Overview The 135 OCP and H Protect detection circuits output a HIGH to indicate problem These HIGHS are input to the latch circuit that then places a LOW at the base of the relay drive transistor This eliminates the current path necessary to keep the unit ON When there is a failure a signal is also sent to 1001 which will indicate these failures by flashing the Standby Timer LED in sequences of two Latch and Hold Down The latch is activated whenever a condition in the 135 volt OCP or the H Protect circuits causes Q506 B to go HIGH A HIGH on Q506 B turns it ON causing it to turn ON Q507 This drops the drive voltage to Relay Drive Q607 B turning it OFF This in turn removes the ground return path for RY602 and the unit shuts OFF During shutdown the voltage from the Standby 7 5 volt line maintains the latch You can determine which of the two circuits is activating the latch by checking the voltage at D520 A with a peak hold meter If that voltage shows a peak near 5 volts there is a problem with the OCP The LOW signal created by the latch is also applied to the HLDWN line through R508 The HLDWN line is connected to 1 1001 at pin 35 When ever this line goes LOW the Self Diagnostics are activated and the Standby Timer LED flashes in sequences of
12. the color temperature to warmer or cooler to match the program Enhanced 16 9 Mode This mode uses vertical compression to enhance anamorphic widescreen video from DVDs Advanced On Screen Menu A new colorful On Screen Menu that is more intuitive and easier to use Preset Program Palette Picture types that are preset These include Vivid Standard Sports and Movie Freeze Memo Allows you to save an item on the screen in the PIP window while the main picture continues in real time Y Pb Pr Delivers optimum picture quality by supplying separate connec tions for luminance Y blue color difference P B and red color differ ence P R Ideal for DVD players and Digital Television DTV set top receiver decoders Speed Surf Tuning Allows faster channel scanning when you hold down the Channel Up Down buttons 3 Board Descriptions 24 and Under BoardName Power Supply A V Inputs DGC Tuner Pincushion H Deflection V Deflection Audio Amp Switches LEDs Audio Processor and SRS Processor CB CRT Drive and N S Amp Syscon Y C Jungle Comb Filter 27 and Over BoardName Power Supply A V Inputs DGC Tuner Pincushion H Deflection V Deflection Audio Amp Dynamic Focus and Quadrapole Focus Dynamic Focus and Quadrapole Focus D Found in KV27FV16 only The differences in layout between the 24 and
13. through R626 R621 is added in order to keep excessive cur rent from being drawn by the switching supply at initial turn ON R621 is placed in series between the negative terminal of D605 Bridge Rectifier and hot ground This resistor is not in place in smaller sets that contain R605 and R606 The negative terminal of D605 Bridge Rectifier is con nected directly to hot ground in these sets D606 is a thyristor that is connected across R621 When the set is turned ON 80 volts is developed across R621 This initial voltage causes D608 to conduct since its zener voltage is 20 volts When D608 is conducting Q601 is ON 0601 keeps C610 from charging when it is ON As the initial inrush current begins to dissipate the voltage across R621 decreases When this voltage drops below 20 volts D608 turns OFF causing Q601 to turn OFF When Q601 turns OFF C610 begins to charge When the charge of C610 a 10 uf capacitor reaches about 14 volts D606 begins to conduct After this occurs the voltage drop across R621 becomes only a few tenths of a volt 13 D603 is a 33 volt zener used for protection It is not activated during initial turn ON because C609 needs to charge C609 is a 100 uf capacitor C609 will not charge to a level of 33 volts before D606 turns ON This keeps the circuit from activating at power ON In the event that there is a problem such as D606 opening during opera tion C609 will charge and D603 will turn ON When D603 turns ON cu
14. two H Protect When the horizontal circuit is operating normally a signal is output from T505 7 that is also used to supply voltage for the 15 volt line This signal is sent through R548 and D519 and is used to maintain the charge of C546 DC voltage created by the charge of C546 is input to IC501 5 Non inverting input through R563 This voltage is compared to a refer ence voltage of 10 4 volts that is derived by a voltage divider consisting of R561 D517 and D518 D517 is used for temperature compensation As long as 1 501 6 is greater than 1 501 5 the horizontal circuit is operating normally The voltage at 1 501 6 is proportional to the High Voltage If the High Voltage becomes excessive the voltage at IC501 5 will become 23 greater than that at IC501 6 This would cause IC501 7 to output a HIGH This HIGH voltage activates the Latch Note This is a departure from the way previous models have worked Typically when the H pro tect circuit was activated it turned ON a transistor that grounded the HP input to the YCJ In turn the YCJ would disable HD 135 Volt OCP Over current is detected by monitoring the voltage across R556 and R553 When this voltage which rises as more current is drawn gets to a level that causes Q505 to turn ON the latch will be activated C534 prevents premature triggering of OCP Three main components generally cause this type of failure They are T505 FBT Q502 H Out and the CRT Drive no
15. 2 2 122 8 IN RUSH CURRENT PROTECT FROM Q602 CREATES AUDIO B CREATES LOW B CREATES 135 1 27 4 25 00 21 Troubleshooting The following table is a list of symptoms that occur when any of the supply voltages are shorted to ground at turn ON This may be helpful in troubleshooting It is important that you take into account all the symptoms to aid in your troubleshooting Voltage Relay Clicks Video Audio Timer HV Power Switch Suspect LED 135 2 power On and No No 4 No Set ON and Q502 200 volt Shutdown Power symptom repeats problem T503 FBT supply chirps 12 2 power On and No No 4 No Set ON and 603 9 Volt Shutdown Power symptom repeats Regulator 1 501 supply chirps Pin and OCP 5 4 clicks Power ON No No 4 No Set ON and 1 604 5 Volt Degauss and OFF symptom repeats Regulator Data and Shutdown problem 9 4 clicks Power ON No No 4 the No Set ON and 1 603 9 Volt Degauss ON and OFF fourth symptom repeats Regulator 1 1301 and Shutdown flash or IC301 stays on Depending on model for several seconds Audio B 3 Normal Yes No Normal Yes Set turns OFF PS401 402 and IC401 402 depending on model 200 2 4 Set ON and Q502 200 volt Shutdown Power symptom repeats problem T503 FBT supply chirps 12 Scan 4 Normal 3 then fourth No Yes 4 Yes Set ON and 502 Out R550 Derived for shutdown symptom
16. BY PH601 PH601 is opto isolator Pins 1 and 2 are connected to 135 volt line and to 602 2 Error Amp These pins are the terminals of an LED Variations in the 135 volt line effect how much light is output from the LED Pins 3 and 4 of PH601 are the emitter and collector of the internal phototransistor The brighter the light from the LED the more current can flow through the C E junction When there is conduction C E voltage from 1 601 4 VIN is applied to 601 1 OCP FB through R644 This DC voltage helps regulate the supply by changing the DC level of the signal created by the quasi resonant operation Changing the DC level alters the ON OFF time of the internal FET This in turn changes the frequency of operation By controlling the frequency the power transfer is con trolled between the primary and secondary windings of T603 This regu lates the supply s output which means regulation is maintained by fre quency control The table below shows the typical operating frequency checked at IC601 3 and the 601 1 voltage under maximum white raster and minimum black raster loads 135 6DCV 145kHz 1 71 VDC IC601 1 Black Raster 136 DCV 200kHz 1 6 VDC 65 B 2 52 5 B o 601 601 Internal Protection 601 has three protection circuits They are over voltage over current and thermal protection OVP The over voltage protect
17. ROM and any other circuits which need power when the set is OFF Converter Operation Operation of the Standby power supply begins when the set is plugged in The AC line voltage is applied across the standby power supply The AC low side is ground for this circuit The AC high side is applied to a half wave rectifier consisting of 0621 and D622 Two diodes are used so there will be protection should one of them fail This voltage is then ap plied to T621 1 SRT Input through R639 R639 is a fusible resistor used for current limiting and failure protection It will open if the standby switch ing circuit draws excessive current Please note that the board has T621 SBT silk screened on it This differs from the service manual which calls T621 SRT When the voltage is applied to T621 1 SRT Input current flows through the winding and R631 to Q621 G 0621 Converter is a FET with added protection When a positive voltage is applied to the gate it begins to conduct drain to source This reduces the voltage at T621 3 to close to zero Normally this would reduce the voltage at Q621 G but a voltage is supplied to the gate through R632 and C630 from T621 4 This voltage is induced into the secondary winding of T621 4 when current flows through the winding between T621 1 and T621 3 The voltage is not permanent due to C630 As C630 charges it reduces the voltage at Q621 G Once this voltage falls below a certain threshold Q621 Converter turns OFF
18. Ree R504 with Q502 6 unsoldered 5V 2005 1 1301 CXA2131AS Y C J B 9V 135V 2nd ANODE _ gt FOCUS 3 H SIZE AND LINEARITY CIRCUIT THIS CIRCUIT A BOARD DIFFERS DEPENDING ON CRT SIZE HORIZONTAL DEFLECTION 7 27 1226 4 21 00 28 Vertical Deflection Overview Since the Vertical Deflection circuitry has changed little in the last few years we will not discuss its circuit description This section of the course will be used to offer troubleshooting tips for repairing BA 5 chassis sets If the vertical section is defective there will be pulses missing on the protect line to Syscon If these pulses are missing Syscon will shut OFF the power relay and the Standby Timer LED will flash in sequences of four Troubleshooting The following is a troubleshooting procedure for the vertical section if you are sure that the sequence of four flashing lights is not caused by a direct short on one of the power supply lines or a horizontal circuit malfunction Remember that the chirping transformer in the power supply may indicate a direct short on a power supply line or a power supply problem and no horizontal is characterized by lack of High Voltage The first step in checking the Vertical deflection circuit is to check the supply voltages at 502 2 and 502 4 If these voltages are missing R549 and R550 should be checked These resistors are 47 ohms a
19. SONY Training Manual Direct View Television BA 5 Chassis Models KV 13FM12 KV 13FM13 KV 13FM14 KV 20FV12 KV 20FS12 KV 24FV12 Circuit Description and Troubleshooting Course CTV 27 KV 27FS12 KV 27FS16 KV 27FV16 32 12 KV 32FS16 KV 20FS12 Sony Service Company A Division of Sony Electronics Inc 1999 All Rights Reserved Printed in U S A SONY isatrademarkof Sony Electronics Circuit Description and Troubleshooting Models 12 KV 27FS12 KV 13FM13 KV 27FS16 KV 13FM14 KV 27FV16 KV 20FV12 32 12 KV 20FS12 32 16 KV 24FV12 Prepared by National Training Department Sony Service Company A Division of Sony Electronics Inc Features Audio Features Video Features Convenience Features Input Output Feature Glossary Board Descriptions Overall Block A board MA or MB Boards CA or CB boards VA or VB Boards D Board Power Supply and Self Diagnostics Protection Self Diagnostics Power ON Degaussing AC Input Standby Supply Power ON Degaussing Shutdown Table of Contents NN GO oo ao 01 Q Ii 11 11 11 11 11 11 Inrush Current Protection Switching Power Supply Startup Regulation IC601 Internal Protection Operating the Supply without a Load Troubleshooting 135 OCP and H Protect Latch and Hold Down H Protect 135 Volt OCP Deflection Block Horizontal Pincushion Vertical Dynamic Focus and Quadra pole Horizo
20. This means no video or OSD will be displayed However the will continue to output these IK pulses One possible method for seeing these lines uses the Service Mode You can enter Service Mode by pressing Display 5 Vol then Power After the is ON press the 1 button 15 times This will bring you to the VSIZ adjustment al though it will not be indicated on the display Press the 6 button until the IK lines are visible If one of the colors is missing troubleshoot the path for that color If all the colors are missing you may have a faulty tube bias Note This method is only valid for BA 5 chassis 35 See if the is outputting a pulse for each color If there is communica tion between the YCJ and Syscon these pulses should be output Their amplitude should be between 1 and 4 volts peak to peak If one of these pulses is missing at the RGB outputs of the YCJ replace it These same pulses should also be present at the RGB inputs of 702 on the CB board If the inputs to 1 702 CRT Drive are good there should be an output as shown below Note it is inverted and much larger CN1303 UDZ TB 17 5 AB R708 HEATER 1 1301 CXA2131AS YCJ AFC BUFFER RGB DRIVE 11CTV27 4 25 00 36 Video Path 27 and above Overview The video path for the 27 inch and above models is very different from the 24 inch and under models The
21. al pair These signals are routed to CN407 and then to CN408 both on the A board This method is used because the Audio amp is in the rear and the headphone jack is in the front of the A board The signal then passes through the headphones and back to CN407 If 39 there are headphones plugged into the headphone jack J401 the audio will not be returned back This may be useful for troubleshooting in the event of a bad headphone jack The back signal to CN407 is then applied to the R or L speaker terminal depending on which channel you are looking at The R and L speaker terminals are connected to the outputs of IC401 Audio Amp Volume Control and Muting Volume control is adjusted by varying a PWM waveform output from the Syscon ICs O Vol pin This signal is connected to CN2009 10 and ap plied through D403 to a filter network consisting of C440 C442 and R432 These components smooth the PWM signal to a DC voltage This DC voltage is applied to 1 401 1 VC1 and 1 401 7 VC2 The DC voltage determines the level of the signal output The mute circuit is also connected to 1 401 1 VC1 and 1 401 7 2 When mute is called for a HIGH signal is output from CN2002 9 Mute This HIGH turns 0410 ON and grounds the VC1 and VC2 terminals This reduces the audio to no volume It should be noted here that these sets have the Auto Mute feature If a BA 5 chassis were tuned to a weak station the audio would be muted When this occurs No S
22. below and the 27 and above models are the addition of the B P and D boards for the added circuits The switches IR detector and front video input have been moved from the A board to the H boards due to the increased cabinet size f eH TT ie E CB Board VB board KV 20FV12 amp KV 24FV12 only 24 Inch and Under 27 Inch and Over KV 27FV16 pictured Overall Block Overview The BA 5 chassis is new for the 2000 model year It is the first of the BA type chassis to cover 13 to 32 models using the FD Trinitron tubes In order to accomplish this parts common to all models are on one board the A board The MA or MB board contain the video processing and Syscon sections If the set contains surround sound audio then it will have a K board CA or CB boards contain the CRT Drive and Velocity Modulation All 27 and above models contain D board Some 27 and above sets contain P and B boards which plug into the MB board These boards are for PIP and a 3D Digital Comb Filter A Board Power Supply The A board contains sections that are common to all models It contains the standby and switching power supplies The Standby supply is an Energy Star complaint switching supply It produces 7 5 volts to be used by the MA AND MB board The MA AND MB board contains a 5V Regu lator to power the System Control The main switching supply pro duces 135 volts Audi
23. ce IC502 Check to be sure that the signal is getting from 1C502 8 to the protect input on the Syscon The Syscon is located on the MA or MB board depending on the size of the set In the case of size or centering problems check the values of input resis tors R517 R518 R519 and R540 12V SCAN D510 DERIVED MW x SUPPLY R550 D514 FROM T503 9 1 1301 CXA2131AS 15 DERIVED SUPPLY FROM 503 7 VERTICAL DEFLECTION 30 C541 PROTECT TO 003 5 MB BOARD FLYBACK GENERATOR 8CTV27 4 20 00 Video Path 24 and Under Overview The following section will discuss the video path for 24 and under BA 5 chassis models These models have two sets of video inputs and a tuner input The rear jack may also have an S Video input These signals are routed through the video switch to the YCJ then to the Comb Filter if necessary back through the YCJ and then output RGB Switching The composite video signals from the rear jack J201 the front jack J202 and the tuner are all input to 1C 1304 Video Switch IC1304 has two inputs that are used to control the switching These inputs are VO and V1 at 1304 2 and 4 The input to these pins comes from IC1001 Control Tuning System at pins 10 and 11 The following table shows the voltage level at these pins for different input selections Input 1304 2 1304 4 V1 Tuner 0 Volts 0 Volts Video 1 3 3 Volts 0 Volts Vi
24. current through the internal FET This voltage is fed to 1 601 1 through R633 This pin is connected internally to two internal compara tors When this voltage reaches 73 volts Comparator 1 in IC601 Con verter turns the internal FET OFF When this occurs a positive going signal is produced at T603 7 due to the collapsing magnetic field This signal is rectified by D614 The rectified voltage is delayed by the charg ing action of C652 The delay time is a factor of the values of R646 R643 and C652 The rectified and delayed voltage from D614 is then sent through D611 blocking diode to 601 1 OCP FB When this voltage reaches approximately 4 volts Comparator 2 in IC601 turns the FET ON This causes a loss of the D614 voltage due to the changes in magnetic field of T605 The voltage across R632 and R641 will increase again and the cycle repeats itself 12601 STR F6624 6654 A BOARD CONVERTER D GND S VIN OCP FB R637 R662 R660 AAA AM R632 2 0610 1 me C647 C644 TO IN RUSH CURRENT R621 LIMIT PROTECT ONLY FOUND IN 24 AND ABOVE MODELS SEE RUSH CURRENT PROTECTION SWITCHING POWER SUPPLY 16 123 7 VDC FROM 135 ERROR FROM 602 2 122 8 IN RUSH CURRENT PROTECT FROM Q602 CREATES AUDIO B CREATES LOW B CREATES 135 1 27 4 25 00 17 ee 4 DC LEVEL CONTROLLED
25. deo 2 0 Volts 3 3 Volts Whichever input is selected will be output from IC1304 7 and then input to 1301 41 separate signals from the video jack are input directly to 1 1301 2 and 4 If the input chosen is composite video that signal will be switched through the YCJ and output at pin 6 Pin 6 is the monitor out line and would have the Y signal present at its output if an S video source were chosen This signal will be used by IC1001 Control Tuning System for V Chip and Closed Captioning and by 1 1302 Digital Comb Filter 31 Digital Comb Filter The Digital Comb Filter is used when composite video inputs are used The composite video signal output at 1C 1301 6 is buffered and filtered by Q1311 Q1312 FL1301 and Q1310 You should note that the chroma signal has a very low amplitude at FL1303 The signal is then input to 1 1302 14 A In There is also 3 58 MHz clock signal output at IC1301 43 FSC and input to IC1302 13 This signal is used by 1302 Digital Comb Filter for timing The Digital Comb Filter has separate Y and C outputs at pins 20 and 17 respectively These signals are both buffered and filtered before being re input to 1 1301 at pins 9 and 7 Y C Processing The YCJ selects which Y and C signal to use for processing If S video is selected then the inputs at pins 2 and 4 are used If composite video is selected the inputs at pin 7 and 9 are chosen Whichever input is cho sen t
26. either side of R630 If either circuit goes low the power relay will turn OFF The LOW from the latch circuit will also be applied to the HLDWN line which is input to 1C 1001 35 for use by Self Diagnostics REPLACED JUMPERS IN 24 AND ABOVE MODELS CN601 A BOARD L THP601 C648 L605 R605 R606 CONVERTER so STANDBY RECTIFIER POWER STANDBY 7 5V D605 SUPPLY R661 ea R607 R630 jus STANDBY 7 5V STANDBY 0602 JE MTZJT 25 2901 CN1004 77 100 R1047 R1048 LATCH FROM Q507 E T 1048 1049 1050 TUNIN 993 p CC SYSTEM M37273MF 258 FROM POWER SW Q608 C FROM REMOTE STANDBY 7 5V OVP FROM POWER ON DEGAUSSING 2CTV27 1228 4 25 00 12 Inrush Current Protection Overview Sets with 20 inch tubes and below use R605 and R606 shown in the Power ON Degaussing section for inrush current protection Since more current is drawn when a set with a bigger CRT is turned ON an alternate inrush current circuit is used for sets with 24 inch and larger CRTs The resistors in smaller sets remain in place after turn ON The larger sets use a resistor that is shunted by an SCR shortly after power ON This allows more current to be drawn without dissipating more power In Rush Current Protection RY602 is closed when the set is turned ON This applies AC to D605 Bridge Rectifier and R637 D605 Bridge Rectifier supplies DC to the switch ing supply
27. for startup is reached at 1 601 4 VIN the oscillator begins operation by outputting its positive half cycle This turns the internal FET ON allowing current to flow as described above When the oscillator starts its negative half cycle the FET is turned OFF and current stops flowing through T603 4 and 5 and T603 2 and 3 15 This switching ON and OFF of the internal FET whose Drain and Source 601 3 and 2 respectively produces a signal output at T603 7 that is rectified by D613 and applied to 1 601 4 VIN DC voltage produced by D613 is used to sustain the input voltage at 601 4 VIN When this sustaining voltage is missing 601 will begin to start up With out this voltage C620 will discharge on the negative half cycle of the incoming AC This causes the 601 to be constantly turned ON and OFF chirping noise accompanies this failure and the Standby Timer LED will flash If the voltage supplied to 1 601 4 VIN exceeds 22 volts the IC will go into internal over voltage shutdown and cease oscillation Regulation 601 Converter is used here quasi resonant operation Quasi reso nant refers to the fact that there are two different levels used to determine how long the internal FET of IC601 should be turned ON or OFF The resistance and capacitance values of the components associated with 601 1 and 2 determine this When the supply is started the voltage created across R632 and R641 monitors the
28. he Y and C signals will be used to create the RGB outputs of IC1301 These signals will eventually be sent to the tube cathodes The YCJ also contains an input for IK to control AKB The YCJ samples this signal and determines if each colors cathode is drawing adequate current If the YCJ determines that there is a problem with the IK loop video will be blanked 1301 communicates this to 1001 Control Tuning System through the bus This IC will then flash the Standby Timer LED in sequences of five to indicate an IK problem IK RETURN FROM Q1331 C 01317 BUFFER NJM2534M 01315 CN2002 CN1003 VIDEO BUFFER 01316 BUFFER OUT IC1301 2202 YIC J CN2001 CN1001 CXA2131AS A BOARD FOR AUDIO SWITCH SELECTO YM SELECT1 OSDBLK Q1311 Q1312 FL1301 01310 C1055 C1053 IC1302 TC90A49P A BOARD MB BOARD DIGITAL COMB FILTER VIDEO PATH 24 AND UNDER 6CTV27 1223 4 24 00 32 RGB Drive Overview This section describes how the RGB signals are displayed by the picture tube In addition we will discuss the IK AKB circuit and how it functions in the BA 5 chassis Troubleshooting no video problems by using the IK pulses output by the will also be covered IK Pulses and Video Blanking When the set is turned ON and communication is established between the YCJ and Syscon IK pulses are output for each color
29. he device is good you will get a resistance reading of about 400 1k ohms Some do not produce enough DC voltage in the ohms mode The diode check mode can be used with these models When using the diode mode a low voltage drop is shown after pre charging the gate 621 0621 4 7 OHMS gt R640 691 A D623 0621 25 2845 FROM R623 amp R664 AC Lo SIDE C630 R632 D626 R638 RD6 2ESB2 STANDBY SUPPLY TO RY600 POWER RELAY 622 7 2VDC 5 STANDBY 5V TO CN1641 TO Q646 E BACKUP 3 26 1187 12 28 99 SONY SEL Service Company A Division of Sony Electronics Inc 1 Sony Drive Park Ridge New Jersey 07656 CTV270500 Printed in U S A
30. he signal to the secondary The secondary signals are used to create three DC voltages that are used to supply power to the rest of the set Feedback from the primary side of the transformer and the 135 volt line created by the secondary is used to control the switching frequency The IC also has three built in protection circuits Startup When power is turned ON RY602 is closed and AC is applied to R637 and D605 The AC applied to R637 is passed through R662 and R660 and applied to 1 601 4 VIN As C620 charges the first positive half cycle of the incoming AC signal its voltage reaches the threshold at which 601 Converter will start to operate This threshold is around 11 volts Once 601 starts operating the incoming AC will not be a factor in sus taining the charge of C620 The voltage at 1 601 4 VIN will remain at approximately 17 VDC during normal operation due to a sustaining volt age which will be created using the signal from T603 7 When AC is applied to D605 144 VDC is developed This voltage is sent through R626 to T603 5 When the voltage across C620 is sufficient to allow 1 601 to operate current flows through T603 5 and T603 4 and T603 3 T603 2 through 601 3 D and 1 601 2 S and finally through R632 and R641 to ground 1 601 3 and 4 are the Drain and Source for an internal FET The gate of this internal FET is connected to an oscillator contained 601 Converter When the voltage threshold
31. ignal will also be displayed on the screen Q411 is a Power Off Mute transistor It is configured so that when the set is turned OFF Q411 turns ON This is possible because the 9 volt line holds voltage longer than the 12 volt line When power is disconnected and voltage remains on the 9 volt line current flows between the B E junction of 0411 This turns the transistor ON and grounds the VC1 and VC2 lines 214 422 C215 R421 C207 R425 C208 R424 MUTE CN2002 CONTROL LINES 1 1405 2 4 VOL FROM 1 1001 3 CN1003 MB BOARD CN2009 CONTROL LINES FROM CN2002 10 amp 11 O VOL gt l AUDIO WITHOUT K BOARD D401 D403 TO CN407 AUDIO B FROM L601 VP 3 IN1 1401 AUDIO AMP TDA7075AQ J401 HEADPHONE eau R BACK R447 L8 RGO K TO e LS L BACK R445 4 s 408 Fs HP GND VC1 VC2 EB R SPK L 1 13CTV27 1230 4 25 00 40 Audio with Board Overview This section discusses the second type of audio circuit that uses the K board The K board allows for up to six different audio source inputs It also contains ICs that perform all necessary audio processing including volume control and SRS SRS is not contained in all models that use the board We will also discuss the second type of Audio Amp Audio Inputs and Processing Larger BA 5 chassis sets can have u
32. ils is used to sharpen focus in the four corners of the picture H DRIVE Q501 T501 IC1301 50 LINEARITY IN OUT IRCUIT 1001 SYSCON 5 27 amp 32 ONLY DEFLECTION BLOCK 9CTV27 1227 4 20 00 26 Horizontal Deflection Overview Since the Horizontal Deflection circuitry has changed little in the last few years we will not discuss its circuit description This section of the course will be used to offer troubleshooting tips for repairing BA 5 chassis sets Troubleshooting The following is a procedure to try if the set is shutting down with a four flashing sequence indication from the Self diagnostics and No High Voltage present The presence of High Voltage for even a short time is an indication that the Horizontal circuit is functioning normally and your problem lies in the vertical section Keep in mind the scan supplies are part of the Horizontal circuit The YCJ should always output HD whenever 9 volts is present You can check this by turning the set and checking 1 1301 19 HD for the sig nal shown below before the set shuts down Another method would be to remove the MB board and connect a 9 volt power supply to the 9 volt line The HD signal should be output from pin 19 1301 19 2V 2005 The only exception would be if 1C1301 18 is shorted to ground This pin serves a dual function
33. ion circuit functions by monitoring the voltage present at IC601 4 VIN If this voltage rises above 22 5 volts the switch ing circuit will be stopped This OVP activates a latch circuit and power must be disconnected for operation to restart OCP Over current protection is done by monitoring the voltage at IC601 1 FB 601 1 OCP FB only operates during the turn ON portion of the FET switching If the voltage passes over the threshold during this time switch ing will stop This will cause the voltage at 1 601 4 VIN to fall below the voltage needed to operate the IC This voltage will rise above the ing threshold on the next positive half cycle of the AC input and cause the FET in IC601 to turn ON If OCP is detected again by IC601 1 the cycle 12601 STR F6624 6654 A BOARD CONVERTER D GND S VIN OCP FB R637 R662 R660 AAA AM R632 2 0610 1 me C647 C644 TO IN RUSH CURRENT R621 LIMIT PROTECT ONLY FOUND IN 24 AND ABOVE MODELS SEE RUSH CURRENT PROTECTION SWITCHING POWER SUPPLY 18 123 7 VDC FROM 135 ERROR FROM 602 2 122 8 IN RUSH CURRENT PROTECT FROM Q602 CREATES AUDIO B CREATES LOW B CREATES 135 1 27 4 25 00 will repeat Every time this cycle repeats a chirping sound can be heard from the power supply This chirp occurs when the VIN voltage rises again to a voltage at which IC601 can operate Th
34. is chirping sound is made each time the supply begins to restart It will continue to repeat until the Syscon IC senses a vertical failure At that time the power relay will be turned OFF and the Standby Timer LED will flash in sequences of four An example of this failure would be a short on the 135 volt line such as VM Output short This type of failure would not be associated with a Horizontal failure such as H Out 200 volt short Video Amp or FBT That circuit contains another OCP that would cause the Standby Timer LED to flash in sequences of two This will be discussed later Thermal The thermal shutdown works by sensing the temperature of the lead frame that the IC is mounted to internally The semiconductor wafer is mounted to a lead frame to dissipate heat When the temperature of the frame reaches 140 degrees Celsius the latch is activated Power must be dis connected for operation to restart Operating the Supply without a Load It is important to be able to isolate whether a problem is in the power supply or other circuitry This supply can be run unloaded at AC input voltages ranging from 30VAC to 120VAC You can unload the supply by unsoldering one side or removing L603 After removing L603 place a jumper across the contacts of RY602 Plug the set into a variac and begin to slowly bring up the AC voltage At about 30 volts the supply will begin to operate The following table shows the state of several points at various
35. ly The Standby Supply powers the System Control IC EEPROM remote sensor and reset circuits If a Power ON command is received after reset the System Control IC outputs voltages to turn ON the Power and Degauss relays When operating correctly the following can be observed in sequence e The power relay clicks e One second later the degauss relay clicks and the hum of the DGC is heard for about two seconds and e The degauss relay clicks again two seconds later and then a picture is displayed This entire sequence occurs in the first 5 10 seconds the unit is powered ON During this time the Standby Timer LED will be flashing approxi mately once per second The main power supply in the BA 5 chassis uses one switching IC to control switching of the through a transformer The transformer pri mary couples the signal to the secondary The secondary signals are used to create three DC voltages which are used to supply power to the rest of the set Feedback from the primary side of the transformer and the 135 volt line created by the secondary are used to control the switching frequency The IC also has three built in protection circuits They are for over voltage over current and thermal protection These protection cir cuits will be covered in the Switching Power Supply section Protection Protection circuits are included to deactivate the set if the following fail ures occur Standby 7 5 volt OVP If over voltage occurs o
36. m Control ICs The different allows for more inputs and also controls video switching in the larger sets In addition the larger sets contain a different System Control IC that is utilized to produce a better OSD and menu system In models that have the PIP function a 2 Tuner and P board will be added to the MA board The P board creates the sub picture using the video from the 2 tuner The KV27FV16 contains a 3D Comb Filter that resides on the B board The B board plugs into the MA board similarly to the P board CA or CB Boards All 24 and under sets will contain the CB board The CB board includes the CRT Drive and North South Drive for tilt correction The similar CA board will be used on all 27 and over models VA or VB Boards Not shown All sets contain a VA or VB board which contains VM Drive D Board Not shown Larger sets will contain a D board This board contains Quadra pole and Dynamic Focus circuits necessary to produce a better picture on larger screen size models YUV Y C AN INPUTS CV VIDEO Y C J E EF DEFLECTION AUDIO i BOARD COMB FILTER OR B BOARD POWER SUPPLY SYSTEM NTROL pec Conger H PROTECT 8 e 135V 135V AUDIO B OVERALL BLOCK 14 27 1231 4 24 00 Power Supply and Self Diagnostics Power Supply When the unit is first plugged in power is applied through the AC In block to the Standby Supp
37. m being heard when no station is received The display will also indicate No Signal in the lower left hand corner models are Stereo with Auto SAP except for the 13 inch models The 13 inch models are mono and contain only one speaker All 24 and under manuals contain a headphone jack All V models contain the Steady Sound Auto Volume BBE hancement and Dynamic Acoustic Chamber DAC features The following table shows the type of surround sound and audio output power Surround Power Output KV 13FM12 N A 3W KV 20FS12 N A BW x2 KV 20FV12 Matrix 5W x2 KV 24FV12 SRS 3D 10W x2 KV 27FS12 Matrix 5W x2 KV 27FS16 Matrix 5W x2 KV 27FV16 SRS 3D 15W x2 KV 32FS12 Matrix 5W x2 KV 32FS16 Matrix 5W x2 Video Features All models contain the following video features FD Trinitron WEGA TV Auto Pedestal Clamp Dynamic Picture Processor Vertical Aperture Compensation Auto White Balance All 20 and above models use Velocity Modulation to enhance the picture All 27 and above use Dynamic Focus Magnetic Quadra pole and Trinitone Color Temperature Adjustment circuits e The KV 27FV16 contains a 3D Digital Comb filter to enhance the pic ture quality It also has Enhanced 16 9 Mode e Convenience Features All the BA 5 models contain the following Convenience features Speed Surf Tuning Clock Timer 2 events Advanced On screen Menu Sleep Timer 15 30 45 60 90 Channel Label V Chip
38. n these signals Once the IK detect circuit in the YCJ detects that the proper current is flowing to each cathode the video is unblanked and a picture may be seen The YCJ continues to monitor the IK IN line for the proper signal levels If there is a failure during operation the Standby Timer LED will flash in sequences of five Tube Bias The CRT requires high voltage and other biasing voltages to properly display a picture First it requires a heater voltage which is developed by the FBT not shown on the A board The heater is necessary to heat the cathode so that it can emit electrons If it is missing the cathode will not emit electrons and consequently there would be no picture The wave form below shows the signal at CRT pin 7 H1 CRT Socket 7 20v 10us The G1 input on the tube is a control grid There are three separate pins on the tube for G1 They are pins 6 9 and 13 These pins are connected together and tied to ground through R715 There is approximately 01 volts present at these pins when no video is input G2 is also a control grid and is used to limit the acceleration of electrons as they travel through the neck of the tube These changes in the accel eration of the beam change the picture brightness G2 measures about 316 volts on a 20 inch sample This voltage will increase as screen size increases G2 is set by inputting a gray scale pattern and adjusti
39. n this line a LOW will be output to the base of the relay drive transistor This shuts the set OFF 135 volt OCP This sensor monitors the voltage across a resistor that feeds the H Out and FBT and protects against 135 volt OCP When OCP is detected the protect latch is activated When the latch is acti vated drive to the relay is stopped This shuts down the main power supply A signal is also sent to the Syscon IC to be used by the Self Diagnostics H Protect Or hold down is used to keep the picture tube from emitting harmful x rays if a failure should occur that causes the High Voltage to rise When this circuit is activated it also turns the latch ON This turns drive to the power relay OFF and sends a signal to the Syscon to be used for self diagnostics AKB Protect Or IK protect causes the video to be blanked if the YCJ does not receive the correct feedback from the IK line The IK line s voltage is representative of the amount of current being drawn by the tube This current is monitored during vertical blanking The YCJ outputs one H line for each color and monitors the returning IK voltage If this voltage is not within the correct operating window the YCJ alerts the Syscon IC via the bus for use by the Self Diagnostics Protect protect occurs when the Vertical Output IC does not return samples of its pump up pulse to the Syscon When these pulses are missing it is an indicator that the vertical section is no
40. nd should always be checked with an ohmmeter because they have a ten dency to change value when subjected to heat They should never read much higher than 47 ohms with an ohmmeter Next check the signals at 1 502 1 and 7 They should look like the wave forms shown below 502 1 1V 5 5 1 502 7 1V 5MS 29 If these signals are missing check IC1301 13 and 14 If these signals are not present check the data and clock lines at 1301 34 and 35 The will not output vertical drive unless communication is okay between the YCJ and the Syscon If data or clock is missing unload these lines from each IC individually When a lead is lifted and the signal returns replace that IC If communication appears normal replace the YCJ If the drive signals are present check the signal at IC502 3 This signal should appear as shown below 1 50273 20V 5MS If this signal is missing replace IC502 If the signal appears distorted is missing the retrace portion check or replace C541 and D510 Check the output from IC502 5 It should look like the waveform shown below SN NRI 1 502 5 20V 5MS If the signal at IC502 5 is missing repla
41. nent input is chosen there will be no signal output from Monitor Out Comb Filter If a composite video signal is selected and output from 1 301 17 it must have the Y and C components separated 02 Digital Comb Filter or the B board can do this The B board is only used on the KV27FV16 37 model and contains a 3D Comb Filter Whichever comb filter is used they will have the same effect on the signal path They each take com posite video input and output separated Y and C These Comb Y and Comb C signals are then re input to the YCJ at pins 22 and 20 respec tively Y C Processing IC301 YCJ then switches the correct Y and C input to the demodulator circuits If the composite source is chosen then the Comb Y and Comb C at pins 22 and 20 are input to the demodulator If one of the S video inputs is chosen then Y and C from pins 12 and 11 or pins 15 and 14 are selected The chosen signals are demodulated to YUV signals Then there is an other switch that switches between these signals and the YUV inputs at pins 50 51 and 52 The chosen YUV signal is then mixed with the PIP YUV inputs These inputs also contain Y SW signal at 1C301 45 which blanks the main picture for the proper size and position of the PIP win dow This signal is then processed further matrixed to RGB and output from 1 301 37 38 and 39 PIP The models that have PIP will use the P board which plugs directly into the MA board The P board accepts comp
42. ng the G2 VR on the FBT not shown so that the darkest bar is completely black This is done with Contrast set to max and Brightness set to the midpoint CN1303 UDZ TB 17 5 AB R708 HEATER 1 1301 CXA2131AS YCJ AFC BUFFER RGB DRIVE 11CTV27 4 25 00 34 There is an input for the focus grid at pin 3 G4 of the tube This input is from the electrical focus control VR on the FBT It should be set for opti mum focus using a dot pattern Pin 1 of the tube CV is used for convergence A part of the H1 voltage is input to pin 1 through RV701 The convergence plates in the tube align the colors to each other using this voltage If any of these signals are incorrect or missing the video may never unblank at turn ON This would leave us with a starting point to troubleshoot blanking problems Blanking can be caused by faulty IK or tube bias operation Troubleshooting The first step in troubleshooting is to determine if there is a tube bias problem or an IK blanking problem Use of the Self Diagnostic feature does not seem to be of any help here You will know if you are in video blanking if the Standby Timer LED flashes continuously or in sequences of five soon after turn ON There should also be HV and sound present If no HV is present the Standby Timer LED should be flashing in se quences of two or four If a problem occurs with one of the colors the set will remain in video blanking mode
43. ntains the SRS IC or not audio will eventually be applied to CN450 5 and 6 From there it will go to the A board via CN460 5 and 6 Audio Amp Once the audio is on the A board it is applied to the same RC network used on models without K boards The values of the resistors in this case will determine if the set will output 10x2 watts per channel or 15x2 watts per channel The signals are applied to 402 using two pins for each channel The output is differential and follows the same path as models without K boards Some larger sets do not contain headphone jacks If the set does not audio is applied to the speakers from the outputs of 402 The outputs of IC402 are applied to the side of the speakers 39 IN2 AUDIO R OUT TO CN407 L OUT TO MUTE CN407 FROM SYSCON 1 1001 5 VIA CN2002 9 404 PROCESSOR NJW1130G 1 402 OUT AUDIO LIN LOUT RIN ROUT VAR FIX OUTPUT TO J402 MON OUT TO J204 SDA SCL R438 C421 IN3 10 TDA8580Q IN4 1 AUDIO WITH BOARD 42 15CTV27 1232 5 16 00 APPENDIX Standby Power Supply Note The following is an excerpt from CTV 26 which covered the AA2W chassis The operation of the Standby Power Supply in the BA 5 chassis is identical but component names are different Overview The standby power supply is a switching power supply used to create Standby 5V The Standby 5V line is used to power the Tuning Micon and EEP
44. ntal Deflection Troubleshooting Vertical Deflection Troubleshooting Video Path 24 and Under Digital Comb Filter 13 15 15 15 17 19 21 23 23 23 23 25 25 25 25 25 27 27 29 29 31 31 Y C Processing RGB Drive IK Pulses and Video Blanking Tube Bias Troubleshooting Video Path 27 and Above Inputs and Monitor Out Comb Filter Y C Processing PIP Audio without K Board Audio Amp Volume Control and Muting 31 33 33 33 35 37 37 37 37 37 39 39 39 Audio with K Board Audio linputs and Processing Audio Amp Appendix Excerpt from CTV 26 Standby Power Supply Converter Operation Regulation Over Current Protection OCP Over Voltage Protection OVP Secondary Output Checking Q621 41 41 41 Features Overview The following section discusses the various features for BA 5 models These features will be separated into four categories Audio Video Con venience and Input Output The BA 5 chassis covers the following mod els KV 13FM12 KV 27FS12 KV 13FM13 KV 27FS16 KV 13FM14 KV 27FV16 KV 20FS12 KV 32FS12 KV 20FV12 KV 32FS16 KV 24FV12 The 13 models are identical except they are different colors The FM12 is gray FM13 is white and the FM14 is blue These models will have the same features as the FM12 listed in the following section Audio Features e All models contain the Auto Mute function Auto Mute mutes the audio when no signal is received This prevents loud static fro
45. o B and low voltage supplies The low voltage supplies are 12 9 and 5 volts The A board contains a degaussing circuit which is activated by the DGC line from System Control This line controls a relay which when acti vated supplies 120 VAC to the degaussing coil Audio The audio section on the A board contains the audio output amplifier There may also be a switching IC that selects the correct audio input if the unit does not contain a K board Any unit that features surround sound audio or SRS will have a K board Video The A board contains front and rear input jacks and the main tuner 24 inch and under sets will have a video input select switch on the A board In other models the video switching will be handled by the YCJ on the MA board Deflection The horizontal vertical and pincushion correction circuits are contained on the A board These circuits control the current through the yokes in order to correctly scan the CRT The FBT produces supply voltages for the vertical output and creates high voltage focus voltage and G2 screen voltage Pulses are monitored by the H protect circuit If these pulses become too large they will activate the latch circuit which will shut down the supply MA or MB Boards The MA AND MB boards contain the YCJ and System Control circuits The MB board will be used on all 24 and under sets All 27 and larger sets will use the MA board These boards use different and Syste
46. osite video from 01 24 PIP Out If the input chosen for PIP by the user is S Video the YCJ combines the separate Y and C and outputs them as composite video from pin 24 The PIP board will also accept inputs from the YUV component input When these signals are input to the P board they are modulated to form a composite video signal This is because the PIP IC on the P board only accepts composite video inputs The PIP processor selects one of the composite video inputs digitizes demodulates and compresses it The reduced YUV signal is output from CN305 12 12 and 14 along with the Y SW signal output from CN305 15 These YUV signals will be placed into the main video YUV signals using the Y SW input VIDEO1 FROM J201 VIDEO3 FROM J203 MON OUT TO J204 DET OUT FROM TU101 VIDEO4 FROM J206 VIDEO2 FROM J202 VIDEO 4 FROM CN2005 CNOO6 C cv CN2006 ICN005 0151 CN2007 0152 CN301 CN302 C348 PR ESSET C359 PB CN2001 THH e pa EH CV C361 C322 C312 P BOARD J4221 M DET IC301 Y C J CXA3154 3 CVBS4 IN FSC OUT 69 VBSS G OUT 88 1 TUNER Q KV27FV16 ONLY VIDEO PATH 27 AND ABOVE 38 CVORY TO IC001 28 FOR V CHIP Q355 FL303 Q352 Q350 TC90A49F Q302 Q369 cour Q370 KV27FS16 KV27FV16 KV32FS16 ONLY TO R BUFFER Q389 TO G BUFFER Q388 TO B BUFFER Q387 10CTV27 1229
47. p to six audio inputs Video 1 through 4 and inputs for two tuners No matter what source is chosen both chan nels of audio are applied to the K board via CN460 and CN450 Then both channels of all sources are applied to 1 404 Audio Processor 1404 Audio Processor contains a switching network that will switch the selected source to the various outputs The selection is performed via commands from the Syscon The audio selected is directly output from 1 404 11 and 30 Monitor Out This signal will be sent to J204 Monitor Out jack on the A board The signals will also be applied to the following internal circuits AGC BBE volume matrix surround sound tone and another volume circuit Data from the bus will determine how much audio processing is formed The left and right signals are output for the Var Fix Output at 9402 on the A board from 1 404 12 and 29 The customer can select from the menu if they want this output to be fixed or variable 41 The outputs from 1 404 13 and 28 are the main audio outputs of the set Depending on the model this audio will be input to 1 403 SRS or to the A board for amplification If the model contains SRS these signals are input at 1 403 23 and 24 The audio is processed by the SRS circuit using the two control outputs from 1 404 22 and 23 These control out puts are used because 1 403 SRS is not compatible 403 then outputs audio from pins 15 and 16 Whether the unit co
48. rrent flows through D607 and R619 This causes Q602 and Q603 to turn ON When 0603 turns ON the VIN voltage from C620 is applied to 601 1 through R644 This causes IC601 to activate its own OCP cir cuit stopping the supply from switching If a failure of this nature were to occur for a very short time less than four seconds the supply could re start itself If the failure lasted longer a sequence of four flashing Standby Timer LED followed by a pause would occur and the Power Relay would be opened The Standby Timer LED will continue to flash in the above sequence until power is removed from the set This removes power from the supply and it ceases to function This is an indication that there is a vertical failure when actually there is a problem in the power sup ply lt 80 volts X 20 volts R621 16 6 volts Q601 B lt 14 volts D606 G Inrush Timing Diagram REGULATION PH601 FROM PC123FY2 1 602 2 PHOTO COUPLER 135V SWITCHING B UM TO T603 5 C620 TO R637 SWITCHING IS SUPPLY REGULATION AC HI R605 R606 kr FROM RY602 D605 T602 3 MTZJ T INRUSH CURRENT PROTECTION 24 AND ABOVE 14 Switching Power Supply Overview The power supply in the BA 5 chassis uses one switching IC to control switching of the B through a transformer The transformer primary couples t
49. rs are inrush current limiters They will be replaced with jumpers in all 24 and above models The Lo side of the line passes through T602 4 and 3 After this occurs AC is applied to the following three circuits They are the Standby Power Supply the Main Switching Supply and the Degauss ing Circuit Standby Supply The Standby Supply is similar to the one used in the AA2W chassis There is an excerpt from CTV 26 included in the Appendix Keep in mind that the circuit is the same functionally but the component identities will be different When AC is applied to the Standby Power Supply circuit it begins to operate and outputs 7 5 VDC This Standby 7 5 volts is applied to the MB board via pin 3 of CN2002 and CN1004 This voltage is input to 1 1305 4 1 1305 is a 5V Regulator that also outputs the 5 volts to be used for reset The Standby 5 voltage is output IC 1305 5 to 1 1001 27 Vcc The reset 5 volts is output IC1305 2 to 1C 1001 30 Reset through RC network This RC network provides the delay necessary for Reset to occur After Reset occurs IC1001 Control Tuning System begins execut 11 ing instructions One of its first tasks is to read and load the contents of the external NVM into the registers of IC1001 via the bus The data in the NVM contains the service data as well as any data relating to cus tomer control settings such as volume level Power ON When the Power On command is received from the Power Switch or the
50. se This brings the frequency of the converter closer to the optimum operating frequency of T621 SRT Moving closer to this optimum frequency causes more voltage to be provided at T621 9 The opposite occurs when the load on the supply decreases This causes the frequency of operation to be in creased and the amount of voltage coupled to T621 9 to be decreased The supply typically operates at 45 kHz when the set is OFF and at about 30 kHz when the set is operating The incoming line voltage also effects the frequency of switching operation 621 0621 4 7 OHMS gt R640 691 A D623 0621 25 2845 FROM R623 amp R664 AC Lo SIDE C630 R632 D626 R638 RD6 2ESB2 STANDBY SUPPLY TO RY600 POWER RELAY 622 7 2VDC 5 STANDBY 5V TO CN1641 TO Q646 E BACKUP 3 26 1187 12 28 99 Over Current Protection OCP Monitoring the voltage across R637 is used for over current protection This voltage is representative of the amount of current flowing through Q621 Converter since it is in series with the transistor If this voltage should rise to 6 volts it will cause Q622 to turn ON If Q622 were to turn ON it would shunt Q621 G voltage to ground This would cause Q621 Converter to stop conducting Over Voltage Protection OVP Over voltage protection is done by rectifying the voltage at T621 6 with D627 This voltage is filtered by C636 and applied to D626 through R638
51. t FROM T501 6 HDT 135 OCP AND 12V PROTECT HLDWN 1001 35 8508 MBBOARD POWER 8861 RELAY R630 RY602 Q607 STANDBY 7 5V Q507 R571 R572 C547 C549 R566 L p A D520 STANDBY 535 7 5V R559 R663 RELAY FROM IC1001 8 9642 gt gt 2002 7 Q604 D619 MTZJ T 77 10B 9608 STANDBY K 7 5V R 55 2 R656 5CTV27 1225 4 21 00 Deflection Block Horizontal 1 1301 YCJ generates the horizontal drive signal and outputs it from pin 34 This signal is first applied to horizontal drive transistor Q501 and is then applied to the horizontal drive transformer T501 and coupled to Q502 the Horizontal Output The signal from the Horizontal Output is sent to the horizontal yoke and the FBT 505 The horizontal deflection yoke controls the beam scan horizontally The Horizontal Output circuit also outputs a sample of the H output that is squared off This signal is called HP is returned to the Pin circuit YCJ phase compensation and the D board on applicable models to create certain signals used by Dy namic Focus and Quadra pole T505 FBT boosts the horizontal drive signal to create the high voltage G2 heater and focus voltages required by the picture tube The FBT creates an ABL signal which is representative of the current drawn by the tube This signal is used to limit the picture brightness and to compen sate for high voltage reg
52. t shown You should check Q502 with an ohmmeter first This component usually fails with a C E short Unloading each of them from the circuit one at a time can eliminate these components Note Before doing this ensure that SW501 H Centering Switch is in the center position Damage will occur to the set if it is not e Unplug the unit Start with the easiest by unplugging CN502 from the A board and reapplying power If the symptom changes from se quences of two flashes to sequences of five flashes replace 1 702 CRT Drive on the C board If the symptom remains unplug the set reconnect CN502 and re move Q502 Re apply power If the symptom changes from sequences of two flashes to sequences of four flashes replace Q502 If the symptom remains unplug the set and remove L510 and R568 These points were chosen because they do not have eyelets Conse quently they are easier to remove compared to unsoldering T505 2 This eliminates the T505 FBT If the symptom changes from sequences of two flashes to sequences of four flashes replace T505 In very rare cases the protection transistor Q505 in this case has be come leaky This can generally be determined by checking the transistor with an ohmmeter or diode checker It is also possible that IC501 has become faulty 4 0518 RD8 2ES 0517 V 561 R565 HV DETECT R548 0519 7 FROM P 5 7505 7 C546 563 556 135 553 pete 8554 n557 C534 C551 9 DRIVE g
53. t working The Syscon IC monitors these pulses for Self Diagnostics and protection pur poses When the pulses are missing the main power supply is turned OFF and Self Diagnostics are activated MA MB BOARD VERTICAL OUTPUT PROTECT STANDBY STANDBY STANDBY 7 5 BV SUPPLY REG IC1001 SYSCON YCJ STANDBY TIMER LED HLDWN AUDIO SWITCHING SUPPLY 22937 LV SUPPLY BOARD POWER SUPPLY AND SELF DIAGNOSTICS BLOCK Self Diagnostics The table below shows the number of times the Standby Timer LED flashes in sequence before pausing and repeating The table indicates what will happen when failures occur while the set is operating Standby Timer LED Diagnosis Standby Timer LED Symptom Problem Blinks repeats 4 times pauses and Shutdown Vertical Failure may also be repeats Horizontal Failure or Power Supply since loss of either will cause no vertical 5 times pauses and 1 No video White balance failure weak repeats 2 Sound OK picture tube or Low G2 voltage Continues to blink No or defective Y C No reply from Y C Jungle IC once a second Jungle 1 301 data bus is busy grounded communications or held HIGH or IK video path is defective at turn ON The set will usually act differently from what is shown in the table when it is powered up with a defect present However indications will still be given that can guide you in troubleshooting
54. ulation In addition scan derived power supplies are generated by the FBT They are the 200 12 and 15 volts Pincushion 60 Hz parabola signal is output from the 1301 11 E W and applied to the Pin Out circuit This signal is compared with the HP signal to create a Pulse Amplitude Modulated signal that is applied to the Horizontal circuit The purpose of this signal is to create a uniform picture width on the screen 25 Vertical The vertical drive signals are generated by the YCJ after it successfully completes initial communication with the Syscon These signals are output from 1C 1301 13 and 14 and are applied to 1 502 Vertical Out The output from IC502 Vertical Out is applied to the vertical yoke to control the scanning of the beam vertically The vertical output also generates a boost pulse that is returned to the Syscon IC for self diagnostics This boost pulse is also sent to the D board to create certain signals Dynamic Focus and Quadra pole The D board is used in all 27 and above models This is because dy namic focus and Quadra pole are necessary for larger FD Trinitron tubes The dynamic focus control uses the VP and HP signals to develop a sig nal which will be used to sharpen the left and right sides of the picture The Quadra pole circuit uses the VP and HP signals along with the posi tive vertical drive signal VD to create a signal that will be applied to a series of coils The magnetic field of these co
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