Tektronix 503A User's Manual
Contents
1. Load Regulation Within 100 mV with a 1 A load change Line Regulation Within 50 mV for a 10 line volt age change Measured at a temperature be tween 20 C and 30 C Ripple and Noise 2 Hz to 2 MHz 5 mV peak to peak or less with a 1 A load Long Term Stability 0 5 or less of drift Overload Protection 2 2 Fixed automatic current limiting and over temperature shutdown REV A AUG 1977 o Specification and Performance Check PS 503A i Table 2 2 PA ENVIRONMENTAL ay DI Characteristics Performance Requirements i Supplemental information Temperature Operating 0 C to 50 C Storage 40 C to 475 0 Altitude Operating To 15 000 feet maximum operating temperature decreased by 1 C 1000 feet from 5000 to 15 000 feet Storage To 50 000 feet Vibration Operating and With the instruments complete and oper Non Operating ating vibration frequency swept from 10 to 55 to 10 Hz at 1 minute per sweep Vibrate 15 minutes in each of the three major axes at 0 015 total dispiace ment Hold 10 minutes at any major re sonance or if none at 55 Hz Total time 75 minutes Shock Operating and 30 g s 1 2 sine 11 ms duration 3 Non Operating shocks in each direction along 3 major axes for a total of 18 shocks Table 2 3 PHYSICAL Characteristic Information pr Overall Dimensions measured at maximum points2. Fig 1 9 Supplies paraliel connected REV B MAR 1977 Performance Conditions The electrical characteristics are valid only if the PS 503A has been calibrated at an ambient temperature between 20 C and 30 C and is operating at an ambient temperature between 0 C and 50 C unless otherwise noted Section 2 PS 503A SPECIFICATION AND PERFORMANCE CHECK SPECIFICATION Items listed in the Performance Requirements column are verified by completing the Performance Check in this manual Items listed in the Supplemental Information column are not verified in this manual they are either explanatory notes or performance characteristics for which no limits are specified Table 2 1 ELECTRICAL CHARACTERISTICS Characteristics Performance Requirements Supplemental Information Plus and Minus 20 V Floating Supplies Voltage Outputs 0 V 4100 mV to at feast 20 V dc 20 1 1 4 V dc with re spect to common terminal or 0 V to at least 40 V dc across the plus and minus terminals Outputs either independently variabie or both variable at a constant ratio of a common control Dual Tracking Variable Current Limiting Less than 100 mA to at least 1A when installed in a high power compartment Less than 100 mA to at least 400 mA when installed in a low power compartment Maximum limit 1 5 A Maximum limit 600 mA Minimum Resolution 50 mV 2 1
3. gt id od Specification and Performance Check PS 503A Table 2 1 cont Characteristics Performance Requirements Supplemental information Load Regulation Transient Recover Within 3 mV with a 1 A load change Within 1 mV with a 400 mA load change lt 20 us for a constant voltage to recover within 20 mV for a nominal output voltage after a 400 mA change in output current Line Regulation Within 5 mV for a 10 line voltage change Ripple and Noise 2 Hz to 2 MHz instrument not in current limiting 3 mV peak to peak or less with a 1 A load 1 mV peak to peak or less with a 400 mA load noise and ripple increase unpredictably when current is being limited Temperature Coefficent 0 025 C or less Stability 0 1 5 mV or less of drift in 8 hours Line voltage load and tem perature held constant Supply Isolation from Ground 350 V dc peak ac Dual Tracking Mode Offset Error If the two supplies are set indepen dently to any given voltage ratio and if both supplies are then monitored and varied a given amount by using the VOLTS DUAL TRACKING control the two supplies will maintain the same voltage ratio as initially set within 50 mV until one supply reaches either 0 V or 20 V 5 V Ground Reference Supply Output 4 75 V de to 5 25 V de with a 5 ohm load Measured at a temperature be tween 20 C and 30 C
4. Height 5 0 inches 12 7 cm Width 2 6 inches 6 6 cm Length 11 75 inches 29 7 cm Net Weight Instrument only 1 Ib 13 oz N 821 grams VA REV A MAR 1978 2 3 f Specification and Performance Check PS 503A PERFORMANCE CHECK Introduction This procedure checks the electrical characteristics of the PS 503A that appear in the Specification portion of this section Limits and tolerances given in the Supplemental Information column are provided for user and service information only and should not be interpreted as re quirements for this Performance Check The electrical characteristics are valid only if the instrument has been calibrated atan ambient temperature between 20 C and 30 C and is operated at an ambient temperature between 0 C and 50 C unless otherwise noted Limits and tolerances given in this Performance Check are for the instrument under test and do not include test equipment error Limits and tolerances in this procedure are instrument performance requirements only if stated as such in the Specification portion of this section Test Equipment Required The following test equipment or equivalent is required to perform the performance check and adjustment procedure Test equipment characteristics listed are the minimum reguired to verify the performance of the equipment under test Substitute equipment must meet or exceed the stated requirements Ali test equipment is assumed to be operating w
5. Error a Pull out the PS 503A VOLTS DUAL TRACKING control and set it fully cew to ensure minimum output voltage while connecting the resistors b Connect the two 4 99 kQ 1 resistors in series between the PS 503A 0 20V green and 0 20V red binding post terminals Do not connect the junction of the two resistors to the COMMON terminal or the chassis c Connect the black patch cord from the digital voltmeter low terminal to the PS 503A COMMON binding post and the red patch cord from the digital voltmeter high terminal to the PS 503A 0 20V red binding post d Set the PS 503A VOLTS DUAL TRACKING control fully cw and adjust the PS 503A VOLTS controls for a meter reading of 18 V 0 1 volt e Connect the red patch cord to the 0 20V green binding post and adjust the PS 503A VOLTS controls for a meter reading of 18 V 0 1 volt f Disconnect the red patch cord from the 0 20V green binding post and connect it to the junction of the two 4 99 kQ 1 resistors Check that the digital voltmeter indicates a dc voltage less than 1 V g Set the digital voltmeter to the 2 volts dc range and adjust either the VOLTS or VOLTS controls on the PS 503A to obtain a meter reading of 0 V de 100 mV h Adjust the PS 503A VOLTS DUAL TRACKING control slowly from cw to ccw i Check that the meter reading remains within 25 mV of zero volts 2 8 j Set the PS 503A VOLTS DUAL TRACKING control fully cew and push th
6. connected supplies against reverse polarity if the load is shorted or one of the supplies is not on POWER POWER SUPPLY SUPPLY NOTE Each supply is connected for 0 to 80 V output Fig 1 8 Supplies series connected Parallel Connected Supplies pra CAUTION innnan Parallel operation is not recommended unless a forward biased diode capable of handling the re quired current and voltage is inserted between each power supply and the load Failure to do this may cause power supply damage The outputs of two or more PS 503 s can be connected in parailel as shown in Fig 1 9 to obtain an output current equal to the sum of the output currents from each supply Each supply must be adjusted individually to obtain the desired output current NOTE The and supplies are internally connected in series Therefore the and supplies cannot be externally connected in parallel to obtain an output current equal to the sum of the currents from each supply One supply should be set for the desired output voltage and the other for a slightly higher voltage The supply set for the desired voltage will then become a constant voltage source while the supply with the higher voltage output becomes a current source due to automatic crossover which results in their output voltage decreasing to that of the supply with the lowest output voitage POWER POWER SUPPLY SUPPLY NOTE Each supply is connected for 0 to 2A output
7. input terminal and set the digital voltmeter to the 2000 mA dc range Reconnect the red patch cord to the digital voltmeter high input terminal c Check for a current reading of less than 100 mA for the 20 V supply The PS 503A CURRENT LIMIT light should be on d Move the red patch cord from the PS 503A 0 20V red binding post to the PS 503A 0 20V green binding post e Check for a current reading of less than 100 mA for the 20 V supply The PS 503A CURRENT LIMIT light should be on f Rotate the PS 503A CURRENT LIMIT control fully cw g Check for a current reading of more than 1000 mA but less than 1500 mA for the 20 V supply h Reconnect the red patch cord tothe PS 503A0 20V red binding post and rotate the PS 503A CURRENT LIMIT contro fully cw i Check for a current reading of more than 1000 mA but less than 1500 mA for the 20 V supply j Set all controls on the PS 503A front panel fully cow and retain the digital voltmeter connections to the PS 503A 3 Check Load Regulation a Disconnect the red patch cord from the digital voltmeter input terminal and set the digital voltmeter to the 20 volts dc range Reconnect the red patch cord to the digital voltmeter high input terminal the meter reading should indicate approximately zero volts Both CURRENT LIMIT lights on the PS 503A front panel should be off and remain off during the load regulation check b Rotate the CURRENT LIMIT con
8. that shuts down the power supply when the voltage rises to about 26 V de POWER SUPPLY NOTE Supply is connected for 0 to 40 V output Fig 1 5 Ground loop created by grounded remote lead 14 POWER ACTIVE SUPPLY LOAD NOTE Supply is connected for 0 to 40 V output Fig 1 6 Reverse current shunt Rs with active load NOTE The point at which the overvoltage protection blows the fuse may be changed for specific applications by changing the Zener diode OPERATION The following steps demonstrate the use of the PS 503A controls and connectors 1 Install the PS 503A into preferably the high power compartment of the power module 2 Press the OUT button to apply power to the PS 503A Observe that the and VOLTS indicator lights come on the lights will be very dim at low voltages Single Supply Operation 20 V Maximum 1 Set the and VOLTS controls for approximately 2V 2 Turn the CURRENT LIMIT controls fully cow to protect the ammeter Connect an ammeter between the common termina and the or terminal and adjust the appropriate CURRENT LIMIT contro for the maximum desired current output REV A MAR 1977 3 Removethe ammeter Connect the load between the common terminal and the or terminal Adjust the or VOLTS contro for the desired output Combined Supply Operation 40 V Maximum 1 Set the and VOLTS control for approximately 2 V and turn the CU
9. to the PS 503A 0 20V green and the COMMON binding post terminals Observe correct polarity for the adapter GND to COMMON i Check that the meter reading does not change more than 3 mV three counts of the most right hand digit 4 Check Line Regulation a Note the exact voltage reading displayed on the digital voltmeter with the adapter and load resistor still attached to the PS 503A 0 20V green and COMMON binding post terminals 19 900 to 19 980 volts Specification and Performance Check PS 503A b Adjust the autotransformer 10 below and 10 above the nominai line voltage setting c Check that the voltage reading displayed on the digital voltmeter does not change more than 5 mV 5 counts for each 10 line voltage change Readjust the autotransformer to the nominal line voltage d Remove the adapter with load resistor from the patch cord jacks Move the red patch cord to the 0 20V red binding post terminal Reconnect the adapter with load resistor to the patch cord jacks Observe correct polarity for the adapter GND to COMMON e Note the exact voltage reading displayed on the digital voltmeter with the adapter and load resistor still attached to the 0 20V red and COMMON binding post terminals 19 900 to 19 980 volts f Adjust the autotransformer 10 below and 10 above the nominal line voltage setting g Check that the voltage reading displayed on the digital voltmeter does not chan
10. RRENT LIMIT controls fully cew to protect the ammeter 2 Connect an ammeter between the and ter minals First adjust one CURRENT LIMIT control for the maximum desired current output then adjust the other CURRENT LIMIT control until the CURRENT LIMIT indicator just reaches maximum brightness i e both supplies at the same CURRENT LIMIT setting 3 Remove the ammeter Connect the load between the and terminals and set the and VOLTS controls so that both settings added together equal the desired output voltage See Dual Tracking Operation for varying the output with the VOLTS DUAL TRACKING control Dual Tracking Operation When pulled out the VOLTS DUAL TRACKING control varies the output of both supplies at a constant ratio from zero to the value set on the and VOLTS controls For example if the and VOLTS controls are set for maximum output approximately 20 V both outputs can be varied from zero to 20V with the VOLTS DUAL TRACKING control 1 1 ratio Likewise if one supply is set for 10 V and the other for 20 V each 1 V change in the 10 V output will be matched by a 2 V change in the 20 V output 2 1 ratio Note also that no matter where the VOLTS DUAL TRACKING control is set the outputs will return to the voltage selected by the and VOLTS control when the VOLTS DUAL TRACKING control is pushed in Therefore rapid selection of two preset outputs from each supply is achieved by merely swi
11. TRACKING control in 6 Adjust the autotransformer to the nominal line voltage and check that the two VOLTS indicator lights on the PS 503A are on 7 Set the vertical deflection factor for 1 mV div and sweep rate for 5 ms div on the test oscilloscope Use ac coupling for the vertical amplifier unit during this procedure 8 Connect all test equipment to a suitable line voltage source 9 Turn on all test equipment and allow at least twenty minutes for the equipment to warm up and stabilize NOTE During warm up time attach banana pins to the leads of the 20 Q and 5 Q load resistors so that they can be inserted in the holes of the dual banana adapter This allows the load resistors to be con nected as close as possible to the output terminals on the PS 503A so contact resistance is kept to a minimum 2 5 l Specification and Performance Check PS 503A Performance Check Procedure 1 Check 0 20 Volt Output Voltage a Check that all controis on the PS 503A front panel are fully ccw and thatthe 400 mA MAX indicator light is off this light should remain off as long as the PS 503A is installed in the high power compartment of the power module Also check that both CURRENT LIMIT indicator lights are off For instruments SN B022064 below these lights may be on if so adjust the appropriate CURRENT LIMIT control cw just enough to turn them off b Set the digital voltmeter to the 2 volts de range Use p
12. Tektronix inc P O Box 500 Beaverton Oregon 97077 070 1834 01 TEKTRONDG PS 503A DUAL POWER SUPPLY INSTRUCTION MANUAL Serial Number First Printing SEPT 1974 pe I I 3 E CI in publication may not be reproduced in any form pat without the permission of Tektronix Inc U S A and foreign Tektronix products covered by U S and foreign patents and or patents pending TEKTRONIX is a registered trademark of Tektronix Inc i I Si INTRODUCTION Description The PS 503A is a dual 0 to 20 V dc constant voltage current limited floating power supply It is designed to operate in the high power compartment of the TM 504 or TM 506 Power Module In the high power compartment it provides a floating dual Oto 20 Vdc at 1 0 A Operatingina standard compartment of a TM 500 Series Power Module the PS 503A supplies a floating dual 0 to 20V de at 400 mA The supply is designed for conveniently powering complementary and linear integrated circuits such as operational and differential amplifiers as well as differen tial comparators A ground referenced 5 V auxiliary supply suitable for bipolar logic light emitting diodes incandescent displays and similar applications is also included With the floating supply available for powering discrete interface circuits and level shifting the PS 503A can be used for many digital analog applications The plus and minus outputs fr
13. atch cords to connect the 20 V floating output ter minals of the PS 503A to the digital voltmeter input terminals connect the red patch cord from the 0 20V red binding post to the digital voltmeter high input terminal and the black patch cord from the COMMON black binding post to the digital voltmeter low input terminal c Check that the PS 503A VOLTS controls are fully ccw and check for a meter reading of 0000 within 100 mV d Set the digital voltmeter to the 200 volts dc range and set the PS 503A VOLTS controls fully cw e Check for a meter reading of at least 20 1 volts but less than 20 4 volts f Adjust the PS 503A VOLTS controls fully cow and move the red patch cord from the 0 20V red binding post to the 0 20V green binding post on the PS 503A g Repeat parts 1c through te using the PS 503A VOLTS controls to check the 20 V supply h Set the PS 503A VOLTS controls fully ccw and move the red patch cord back to the 0 20V red binding post on the PS 503A Check to be certain that all PS 503A front panel controls are fully cew 2 Check Variable Current Limiting a Adjust the PS 503A VOLTS controls for 5 0 V output Move the red patch cord to the PS 503A 0 20V green binding post and adjust the PS 503A VOLTS controls for 5 0 V output Move the red patch cord back to the PS 503A 0 20V red binding post 2 6 b Disconnect the red patch cord from the digital voltmeter high
14. e contro knob in Disconnect both patch cords and the two resistors from the binding post terminals 7 Check 5 Voit Output Voltage a Connect the digital voltmeter between the 5V 1A ground referenced red binding post and the ground white binding post b Push in the OUTPUT button and check that the two VOLTS indicator lights are on c Check for a meter reading of 4 75 to 5 25 volts d Connect a 5 resistor between the 5V 1A ground referenced red binding post and the ground white binding post e Check that the meter reading does not change by more than 100 mV 8 Check 5 Volt Output Voltage Regulation a Adjust the autotransformer output voltage from the low limit to the high limit as indicated in Tabie 2 5 b Check that the digital voltmeter reading does not change more than 50 mV for a plus 10 or minus 10 line voltage change c Disconnect the digita voltmeter d Connect the probe of the test oscilloscope between the 5V binding post and the ground white binding post e Adjust the autotransformer output voltage from the low limit to the high limit as indicated in Table 2 5 f Check the test oscilloscope display for not more than 5 mV peak to peak ripple and noise g Return the autotransformer to the nominal line voltage setting h Disconnect the test oscilloscope probe from the binding posts i Press and release the PS 503A OUTPUT button to turn off the power to
15. ge more than 5 mV 5 counts for each 10 line voltage change Readjust the autotransformer to the nominal line voltage 5 Check Ripple and Noise a Disconnect the patch cords from the PS 503A 0 20V red and COMMON binding post terminals and reconnect the duai banana adapter with load resistor directly to the 0 20V red and COMMON binding post terminals observe correct polarity of the adapter GND to COMMON b Connect the output of the adapter to the vertical input of the oscilloscope using a 42 inch bnc cable Set the oscilloscope vertical deflection factor for 1 mV div calibrated c Slowly adjust the autotransformer output voltage 10 below and then 10 above the nominal line voltage d Check the signal display on the oscillosocpe for less than 3mV_ peak to peak within three vertical divisions at all points of the specified voltage limits e Readjust the autotransformer to the nominal line voltage 27 Pi t f t r il I i Specification and Performance Check PS 503A f Connect the adapter with load resistor attached to the PS 503A 0 20V green and COMMON binding post terminals observe correct polarity of the adapter GND to COMMON g Repeat steps 5c through 5e to check the ripple and noise of the PS 503A 20 V supply h Readjust the autotransformer to the nominal line voltage and disconnectail connections from the PS 503A 6 Check Dual Tracking Mode Offset
16. ircuitry applications the load might behave as a current source for part of its operating cycle Since the output circuit of a series regulated supply is unidirectional current will not pass in the opposite direction except through undesirable paths The internal reverse current diodes conduct only when the PS 503A terminal voltage reverses and therefore will not work when the voltage is correctly polarized Connec REV A MAR 1977 400 mA LIMIT Indicator Light emitting diode in dicates when PS 503A is instalied in a standard compartment of a power module limiting the current output VOLTS Controls and indicators Variable coarse and fine controls provide con tinuously variable or voliage selection from the respective 0 20 volt supply The presence and vafiability of output voltage is verified by voltage indicator lights OUTPUT button pressed Brightness of fights varies with output voltage Floating Output Terminals 5 way binding post ter minais that provide either a positive 0 20 volts between the binding post on the right red and COMMON or a negative 0 20 volts between the binding post on the left green and COMMON When the PS 503A is in stalled in the high power compartment of a TM 504 or TM 506 power module that has a high power compartment the current available at either the or outputs is from tess than 100 mA to at least 1 A When the PS 503A is installed in a s
17. ithin tolerance Special test devices are used where necessary to facilitate the procedure Most of these are available from Tektronix Inc and can be ordered through your local Tektronix Field Office or representative Table 2 4 LIST OF TEST EQUIPMENT REQUIREMENTS r Performance Description Requirements Application Example Oscilloscope Bandwidth de to 2 MHz Used throughout pro Tektronix 5110 minimum defiection factor cedure to provide 5B10N 1 mV div sweep rate display Oscilloscope 10 ms div to 1 us div System Digital voltmeter Range zero to 1000 volts Voltage measurements Tektronix DM 501 accuracy within 0 1 Digital Multimeter Power Module Four compartments or more All tests Tektronix TM 504 with one high power or TM 506 compartment J Autotransformer Capable of supplying an Regulation and General Radio with ac volt output voltage from 90 ripple checks W10MTR3W Variac meter to 132 volts ac 120 W Autotransformer of power at the upper limits Coaxial cable Impedance 50 Q length Provides signal inter Tektronix Part No 42 inches connectors bne connection 012 0057 01 Patch cord Banana plug jack to banana Provides signal inter Tektronix Part No 2 required plug jack length 18 inches connection 012 0031 00 black i 012 0039 00 red 24 Cu Specification and Performance Check PS 503A Table 2 4 cont Perfo
18. nformation Test Equipment Required The test equipment listed in Table 2 4 or equivalent is required for adjustment of the PS 503A Specifications given for the test equipment are the minimum necessary for accurate adjustment and measurement All test equip ment is assumed to be correctiy calibrated and operating within specification If other test equipment is substituted control settings or calibration setup may need to be altered to meet the requirements of the equipment used Preparation a Remove the left hand and right hand side covers of the PS 503A to gain access to the component side of the circuit boards Pull the rear end of the side cover outward from the side of the instrument the cover snaps into place b Install the PS 503A into the far right high power power module compartment or if appropriate connect the PS 503A to the power module by means of the flexible plug in extender If a flexible extender is used current limiting switch S95 must be engaged in the maximum current HI position See Fig 3 1 for switch location c Set the power module for the line voltage to be applied see power module manual and connectit to the autotransformer then connect the autotransformer to the line voltage source Be sure that the power switch is off Section 3 PS 503A ADJUSTMENT d Install ail TM 500 series equipment including the PS 503A into the power module e Connect all test equipment to a sui
19. nserting the plug in otherwise damage may occur to the plug in circuitry Because of the high current drawn by the PS 503A it is also recommended that the power module be turned off before removing the PS 503A Refer to Fig 1 2 Check to see that the plastic barriers on the interconnecting jack of the selected power module compartment match the cut outs in the PS 503A circuit board edge connector Align the PS 503A chassis with the upper and lower guides of the selected compartment Push the module in and press firmly to seat the circuit board in the inter connecting jack To remove the PS 503A pull on the release latch located in the lower left corner until the interconnecting jack disengages and the PS 503A will slide out Controls and Connectors Refer to Fig 1 3 Even though the PS 503A is fully calibrated and ready to use the functions and actions of the controls and connectors should be reviewed before attempting to use it Press the OUTPUT button to apply power to the PS 503A 1 1 l Operating Instructions PS 503A POWER MODULE Bier rin i Barrier Bottom Groove Fig 1 2 Plug in module instaliation removai OPERATING CONSIDERATIONS Overheating The PS 503A is designed to operate at an ambient temperature from 0 C to 50 C However when operating several power supplies in a multi plug in power module especially at low output voltages or when operating close to other heat prod
20. om the dual floating power supplies are independently variable or both variable at a constant ratio by a common control Each supply provides either a plus or minus 0 to 20 V de with respect to the common terminal By connecting across the plus and minus terminals the PS 503A can provide 0 to 40 V dc Either terminal may be grounded or floated to 350 V dc peak ac Each supply also features con tinuously variable current limiting from less than 50 mA to 400 mA standard compartment or 1A high power compartment at both 20 V and 40 V output The presence and variability of the output voltage is verified by the VOLTS indicator light on the front panel The brightness of this light varies with output voltage A panel mounted light emitting diode LED indicates when the PS 503A is operating in a standard compartment of a TM 500 Series Power Module and the output current is limited to a maximum of 400 mA Other panel mounted light emitting diodes indicate when either the or supply goes into current limiting Hard limiting is in dicated by maximum brightness of the light emitting REV C MAR 1977 Section 1 PS 503A OPERATING INSTRUCTIONS diode as well as a dimming of the VOLTS indicator light if the supply output voltage is above approximately 10 V These functions are easily verified by momentarily shor ting the output of the supply Installation and Removal SSIS CAUTION 2 ae Turn the power module off before i
21. proximately 80 Q At that crossover point the supply set for 0 5 A E becomes a current source and its output CURRENT IN AMPERES Fig 1 7 Output characteristics with various currents voltages and loads 1 5 P d Operating Instructions PS 503A voltage decreases with the load At approximately 40 Q and 20 V supply E no longer contributes to the power output Subsequently supply E supplies all the output power and operates as a constant voltage source with output current variable with the load Then at ap proximately 20 Q supply E crosses over and becomes a current source at its maximum output of 1 A Thus by choosing the appropriate load limits and control settings any of the four operating characteristics is possible A second stair step output can be preselected and switched in or out with the VOLTS DUAL TRACKING control see Dual Tracking Operation for details on the function of the VOLTS DUAL TRACKING control Series Connected Supplies The outputs of two or more PS 503A s can be con nected in series as shown in Fig 1 8 to obtain an output voltage equal to the sum of the output voltages from each supply Each supply must be adjusted individually to obtain the desired output voltage see Dual Tracking Operation for varying the output of both supplies with the VOLTS DUAL TRACKING control NOTE The PS 503A has internal diodes connected across the output to protect the series
22. red patch cord from the 0 20V red binding post to the 0 20V green binding post i Check that the digital voltmeter display indicates a current reading of more than 400 mA but less than 600 mA The CURRENT LIMIT light should be on j Set the PS 503A CURRENT LIMIT control fully ccw k Check that the digital voltmeter indicates a current reading of less than 100 mA The CURRENT LIMIT light should remain on I Move the red patch cord from the 0 20V green binding post to the 0 20V red binding post and set the PS 503A CURRENT LIMIT controi fully cew m Check that the digital voltmeter indicates a current reading of less than 100 mA The CURRENT LIMIT light should be on n Turn off all power to the power module Push and release the PS 503A OUTPUT button and set all other front panel controls fully cow o This completes the Performance Check Procedure for the PS 503A Introduction This adjustment procedure is to be used to restore the PS 503A to original performance specifications Adjust ment need not be performed unless the instrument fails to meet the requirements listed in the Specification section or the Performance Check cannot be completed satisfac torily Services Available Tektronix Inc provides complete instrument repair and adjustment at local Field Service Centers and at the Factory Service Center Contact your local Tektronix Field Office or representative for further i
23. rmance Description Requirements Application Example Adapter Bnc female to dual banana Provides signal inter Tektronix Part No piugs connection 103 0090 00 Load resistor 20 9 20 W 5 Load tests Tektronix Part No two 10 Q 10 Win series 308 0246 00 Load resistor 50 5 W 5 Load tests Tektronix Part No 308 0179 00 Resistor 2 required 4 99 kQ 1 2 W 1 or better Dual tracking detector test Tektronix Part No 323 0260 00 1X passive probe Compatible with 5A series amplifiers used in Provides signal inter connection Tektronix P6028 Probe oscilloscope Requires TM 500 Series Power Module Preliminary Procedure 1 Ensure that all test equipment and the PS 503A under test are suitably adapted to the line voltage to be applied Refer to the instaliation section of the power module manual 2 Be certain that the POWER switch on the power module is off and that the OUTPUT pushbutton on the PS 503A is in the out position 3 Install the PS 503A in the far right high power compartment of the power module 4 Connect the power module to the autotransformer and connect the autotransformer to the line voltage source Set the autotransformer voltage output control for zero volt output 5 Set all front panel controls on the PS 503A fully counterclockwise ccw Apply power to the power module and press in the OUTPUT pushbutton on the PS 503A Push the PS 503A VOLTS DUAL
24. table line voltage source f Turn on all test equipment and allow at least twenty minutes for the equipment to warm up and stabilize g Set the autotransformer to the nominal line voltage setting Initial Control Settings Set the following controls during warm up time PS 503A Dual Power Supply VOLTS coarse and fine fully cow VOLTS coarse and fine fully cww CURRENT LIMIT Pius suppiy fully cow Minus supply fully cow VOLTS DUAL TRACKING pushed in and fully cow R45 20V Adj Fig 3 1 Location of 20 V and 20 V adjustment q Adjustment PS 503A 1 Adjust 20 Volt Output Voltages a Check that ali controls on the PS 503A front panel are fully cow and the 400 mA MAX indicator light is off this light should remain off as long as the PS 503A is installed in the high power compartment of the power module Also check that both CURRENT LIMIT indicator lights are off For instruments SN B022064 below these lights may be on if so rotate the appropriate CURRENT LIMIT control cw just enough to turn them off b Set the digital voltmeter to the 2 volts de range and check for a meter reading of zero volts 100 mV c Set the digital voltmeter to the 200 volts dc range Use patch cords to connect the plus 20 V floating output terminals of the PS 503A to the digital voltmeter input terminals red patch cord from the 0 20V red binding post to the digi
25. tal voltmeter high input terminal and the black patch cord from the COMMON black binding postto the digital voltmeter low input terminal d Turnthe PS 503A VOLTS fine and coarse controls fully cw e Adjust R45 20 Adj for a meter reading of 20 2 volts 0 1 volt See Fig 3 1 for adjustment location f Adjust the PS 503A VOLTS fine and coarse controls fully cow and move the red patch cord from the 0 20V red binding post to the 0 20V green binding post g Turn the PS 503A VOLTS fine and coarse controls fully cw h Adjust R145 20 Adj for a meter reading of 20 2 volts 0 1 volt See Fig 3 1 for adjustment location i Adjust the PS 503A VOLTS fine and coarse controls fully cow j This completes the adjustment portion of this procedure However to verify satisfactory performance after adjustment perform the complete Performance Check procedure as specified in Section 2 of this manual REV A AUG 1977
26. tandard compartment the current available is from tess than 100 mA to at least 490 mA 0 to 40 volt out put is obtained between the and output ter minats REV B MAR 1977 Operating Instructions PS 503A VOLTS DUAL TRACKING Control When pulled out varies both the and outputs from 0 volts to the value set on the and VOLTS controls The ratio be tween the and outputs is maintained throughout f the range of the VOLTS DUAL TRACKING DUAL TRACKING con ARRE trol OUTPUT Pushbutton When pressed applies power to both 0 20V binding post terminals and the 5V binding post terminal CURRENT LIMIT Controis and Indicators Continuousty variable controls that select the and output current limit Light emiliing diode in dicates when hard limiting occurs 5 Ground Referenced Output Terminats way binding post termi nals that provide a ground referenced 5 V 1A fixed output 1834 05 Fig 1 3 PS 503A controls and connectors p i i 2 i DI Operating Instructions PS 503A NOTE Suppiy is connected for 20 to 40 V output POWER SUPPLY Fig 1 4 Monitor and ioad connections ting a shunt resistor Rs as shown in Fig 1 6 provides an external reverse current path to the power supply sources or delivers current only Over voltage The PS 503A is protected from over voltage conditions by an over voltage protection circuit
27. tching the VOLTS DUAL TRACKING control in or out When the and supplies are connected as described under Combined Supply Operation the VOLTS DUAL TRACKING control will vary the output from zero to the value selected by the and VOLTS controls added together REV B MAR 1977 Operating Instructions P 503A Stair Step Operation The PS 503A can be operated to provide a stair step output characteristic by choosing certain load limits and control settings For example Fig 1 7 shows the stair step output from the PS 503A when a variable load Ri is connected between the and output terminals With each supply set for maximum voltage and current 40 V 1 A the output voltage remains constant from open circuit until the load reaches approximately 40 Qas illustrated by the solid line in Fig 1 7 At this crossover point the output voltage decreases with the load and the output current is limited at 1 A Therefore below approximately 40 Q both supplies act as current sources with output voltage variable with the load Since both supplies are set for the same output voltage each supply shares equally in the power output I R If one supply is set for a lower output voltage than the other output power is shared at the same ratio as the output voltage Now by setting supply E foracurrentlimit of 0 5 Aand varying the load over the same range the supplies act as constant voltage sources until the load reaches ap
28. the PS 503A Table 2 5 POWER MODULE UNIVERSAL TRANSFORMER Line Regulating Ranges Selector Block Position 110 Volts Nominal 220 Volts Nominal L 90 VAC to 110 VAC 180 VAC to 220 VAC M 99 VAC to 121 VAC 198 VAC to 242 VAC H 108 VAC to 132 VAC 216 VAC to 264 VAC Line Fuse Data 1 6 A slow blow 0 8 A slow blow 9 Check Variable Current Limiting a Turn the power off to the TM 500 Series Power Module and remove the PS 503A from the high power compartment and instail the PS 503A in the low power compartment b Turn on the power to the power module and press the PS 503A OUTPUT button in Set all front panel controls fully cow and allow approximately three minutes for the equipment to stabilize c Check that the 400 mA MAX indicator light is on d Adjust the PS 503A VOLTS and VOLTS coarse controls to the 4 V position leave the fine controls fully ccw e Set the digital voltmeter to the 2000 mA position and connect the black patch cord from the digital voltmeter low terminal to the PS 503A COMMON binding post and the red patch cord from the digital voltmeter high terminal to the PS 503A 0 20V red binding post Specification and Performance Check PS 503A f Set the PS 503A and CURRENT LIMIT controls fully ow g Check that the digital voltmeter indicates a current reading of more than 400 mA but less than 600 mA The CURRENT LIMIT light should be on h Move the
29. trolonthe PS 503A fully cw c Adjust the PS 503A VOLTS fine and coarse controls for a meter reading between 19 900 and 19 980 volts Note and record the exact open circuit voltage reading before applying the adapter with load resistor attached in part d of this step d Insert the leads of the 20 9 5 resistor into the holes of a dual banana plug adapter and connect the adapter to the patch cord jacks which remain connected to the PS 503A 0 20V red and the COMMON binding post terminals Observe correct polarity for the adapter GND to COMMON e CHECK that the meter reading does not change more than 3 mV three counts of the most right hand digit NOTE If the reading on the digital voltmeter changes by more than 3 mV another 20 Q load resistor havinga resistance value closer to 20 should be used or the voltage output from the PS 503A can be reduced to 19 000 step 3c f Remove the adapter with load resistor from the PS 503A patch cord jacks Move the red patch cord to the 0 20V green binding post terminal g Adjust the PS 503A VOLTS fine and coarse controls for a meter reading between 19 900 and 19 980 volts Note and record the exact open circuit voltage reading before applying the adapter with load resistor attached in part h of this step h Insert the leads of the 20 Q 5 resistor into the hofes of a dual banana adapterand connectthe adapterto the patch cord jacks which remain connected
30. ucing equipment inter nal temperature may exceed safe limits and actuate a thermal cutout in the power module Refer to the power module instruction manual for more complete informa tion Load and Monitor Connections Improper connections between the power supply out put and the load s or monitoring device s are acommon cause of errors Multiple loads or monitoring devices must be connected directly to the output terminals with separate pairs of leads as shown in Fig 1 4 Avoid using clip leads since their contact resistance can exceed the output impedance of the PS 503A and cause significant measurement error 1 2 Grounded and Floating Operation The PS 503A is a and 20 V floating supply since no internal connections are made to either the chassis or ground The supply can thus be used as a positive or negative supply by simply connecting between the com mon and the negative or positive output terminal However there may be undesirable effects caused by grounding the supply to the chassis while the load is grounded at some point removed from the supply chassis For example if a remote load is connected as shown in Fig 1 5 ground currents containing the power line frequency could result and create excessive noise and ripple in series with the load Thus floating operation is recommended to ensure against problems caused by undersirable ground currents Reverse Current Loading In some bias supply and digita c
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