Goldstar MBM-2105GIA User's Manual
Contents
1. internally fixed by resistor C601 R603 are used to determine the free running frequency the oscillator free running frequency is given by To 0 15 x C601 x R603 3 2 COMPOSITE VIDEO INPUT PIN 15 VR ADJ USTMENT REGULATED B AD USTMENT VR901 Connect high impedance voltmeter between TR901 emitter and ground rotate the B adjustment control VR901 to obtain a reading of 12 0 0 1 FOCUS VR704 Adjust the focus control VR704 for best overall focus of the test pattern marked with the symbol 95 Usually the center and corners of the screen do not focus at the same setting and a compromise must be made VERTICAL SIZE VR601 The vertical size control VR601 should be adjust for the picture to fill the screen vertically HORIZONTAL SIZE L703 The horizontal size control H site coil should be adjusted for the picture to fill the screen horizontal ly 9 HORIZONTAL POSITION VR701 The horizontal position control VH701 snould be adjusted for the horizontal picture position SUB BRIGHT VR703 Adjust subbright control VR703 for visual cut off of the raster when brightness is turned to maximum CENTERING A ADJUSTMENT It the raster is not centered horizontally and verti cally it may be centered by removing the cabinet back and adjusting the centering tabs on the neck of the tube located at the rear of the deflection yoke Turn the whole device clockwise or countercloc2. SEMIFIX 162 3 8 VARIABLE 250KB SEMIFIX SR 19R 2208 1 8W 75 ohm 1 8W 120K ohm 1 8W 82K ohm 8 680 ohm 1 8W 220 ohm 1 8 390 ohm 1 8W 100 ohm 8W 56 ohm 1 8W 10K oh m 1 8W 1 ohm 1 8W 75 ohm 1 8W 82 ohm 1 8W 47 ohm 1 8W 2 4K ohm 1 8W 3 ohm 2W 1 2K ohm 1 8W 330 ohm 1 8VV 120 ohm 1 8W 1 OK ohm 1 8W 100 ohm 1 8 4 7K ohm 1 8W 33 ohm 1 8 1 5 ohm 1 8 560K ohm 1 8W 2 2 ohm 1 8W 18 ohm 1 8W 150K ohm 1 8 390K ohm 1 8W 82K ohm 1 8W 2 2 ohm 1 8W 1 OK ohm 1 8 82 ohm 1 8W 6 8K ohm 1 8W 150 ohm 1 8W 150 ohm 1 8W 560K ohm 1 8W 3 ohm 1 8W 47K ohm 1 8W 33K ohm 1 8W 470 ohm 1 8W 33 ohm 1 2W 6 8K ohm WMH XI 1 CE 47uF 16V CE 220uF 16V CE 22uF 16V 470uF 10V CE 100uF 16V C C 120pF 50V CE 47uF 10V CE 22uF 100V CC 100pF 50 CE 1OuF 16V CO 0 22uF 100V CE 220 L 16V CE 47uF 16V 0 tuF 100V CE 1000uF 16V CO 0 22uF 100V CO 0 001uF 100V LI 1 gt 0 2 DD D DAD DD DDD DD DDD DI C608 CE 2 2uF 160V A 1 KTD880 O S C701 CE 100uF 16V TR902 1959 S C702 CO 0 1uF 100V TR903
3. Turn this knob to adjust the horizontal size of the picture CIRCUIT DESCRIPTION 1 VIDEO AMPLIFIER The Fig 3 details the cascade video amplifier Video amplification is provided by the TR303 and TR304 TR303 and TR304 are connected in cascade configuration TR303 operates as common emitter and TR304 operates in the common base configuration This minimized the miller effect input capacitance and the difining breakdown parameter for TR303 which becomes BVCBO as opposed to BVCEO This enables selection of a higher speed lower breakdown transistor to be used in the video amplifier The emitter of TR304 is driven by the collector of TR303 which is a high frequency transistor Overall voltage gain for the stage is determined by the ratio of R312 to R316 Bandwidth is within 3dB to 32 MHz 7000 C305 100uF 16V 61 47uF 10V 2 POWER SUPPLY The 120V AC line voltage is applied to the primary of the T901 where it is stepped down through the secondary winding to approximately 17V AC After passing through the bridge rectifier circuit and filter C905 the regulated DC supply voltage is approximately 18V DC The 18V unregulated B voltage is applied directly to the collector of the regulator TR901 A voltage divider network R905 VR901 R906 in which the adjustment control VR901 is used to establish the desired operating level 12V DC When AC input voltage variations occur a correction vo
4. 19 0043 1815 5 703 CE 1 OuF 25V CO 0 0022uF 100V PP 0 0022uF 200V CO 0 0022uF 100V CQ 0 015uF 100V 4 7uF 25V PP 0 027uF 400V 470uF 25V 220uF 16V BP 4 7uF 25V CE 100uF 100V CE 100uF 100V CK 0 01uF 1000V CC 56pF 50V CO 0 0047uF 100V 0 OtuF 50V CK 0 0047uF 50V CK 0 0047uF 50V CK 0 0047uF 50V CK 0 0047uF 50V CE 2200uF 25V CK 0 tuF 50V CE 47uF 16V MPP 0 1uF 125V CK 0 0022uF 125V 0 0022 7 F901 5901 NE301 G301 VIDEO IN SIGNAL CABLE V1 v2 20 0040 20 0039 20 0038 07 0009 PEAKING PL 4 7uH PEAKING PL 3 3uH CHOKE 10uH H LINEARITY COIL WIDTH PEAKING PL 10uH LINE FILTER CRT 310KGB31 Green CRT 310KGB4A Amber FBT DY ASSY PCB MAIN FUSE 0 75A 250V SWITCH POWER NEON LAMP 95V SPARK GAP JACK RCA PHONE RCA TO RCA CABLE SOCKET CRT WIRE ASSY SHIELD TRANS POWER SHIELD PWB LINE FILTER DID DAAN 00 00 02 0 AC POWER CORD 16701 06300159 si CONNECTOR ASSY FOR 901 CONNECTOR ASSY FOR LED 22200 2 051555 1 N4002 KDSI555 KIT PRINTING ZENER 8 2 OWNER S MANUAL 051555 STAPLE NO 10 091555 BAG PE 866250 RGP20G RGP10D RGPIOD RGP10M 1N5392GP 1N5392GP 1N5392GP 1N5392GP ZENER 2 83 6 2 LED GREEN TRANSISTOR TR301 19 0046 KTC 1959 Y
5. 8310 R315 R314 8312 CHECK CRT CATHOD VOLTAGE 45 55V TROUBLE IN VR703 SUB BRIGHT 8710 R711 VR301 CONTRAST HORIZONTAL VERTICAL NO VERTICAL DEFLECTION VRT05 EXT 18301 TR302 VIDEO CABLE SYNC TROUBLE ONE HORIZONTAL LINE AT CRT SCREEN CENTER TROUBLE IN TROUBLE IN 16701 8701 R702 DY 601 8603 C601 C702 C605 R606 R609 R605 C607 R608 C606 VR601 D601 HORIZONTAL vNOTROUBL TROUBLE IM TR301 TR302 18902 18903 NO HORIZONTAL DEFLECTION ONE VERTICAL LINE AT CRT SCREEN CENTER TROUBLE IN DY C712 702 DESCRIPTION KTC 1015 KTC 1959 562 8719 C716 8708 R720 C717 C706 C707 R704 VERTICAL SYNC TROUBLE TROUBLE IN TR601 1815 t KTC 2229 8 1C701 806 880 act 9 TEA 2037A RETRACE LINE TROUBLE i TROUBLE IN R610 D603 D604 R611 TR601 R612 C608 c TR303 2N 3904 B E Figure 5 TRANSISTOR amp IC BASING PRINTED CIRCUIT BOARD 806C ASSY PIN 1 10 MAIN PCB 1 0XXM35 30 ADSZVWSLEL 52 10 A0SZ Vugc L B72A ASSY PIN 110 x d 2112 LINE FILTER PCB GSEP 2 o 3 MAIN PCB SOLDER SIDE 063 062 VM09 L gt 4 LINE FILTER PCB SOLDER SIDE EXPLODED VIEW 0 Outer Cabinet not used 6300
6. 2 1313 7 50Ve 222 gt 8 20 E 5 860 R610 ESI D604 051555 05 IV HDY 3 LI Ar A 1 vR705 7 2 1 BRIT C607 0 001 100M 7 CAME PE bU 1 AR HN D7 pier bs 200 Hj 4 IMPORTANT AVIS SUR 1 S CURIT TES SPECIAL LA N SYMBOLE MARQUE DE CE DIAGRAMME SCHEMATIQUE COMPREND DIMPORTANTES FIRE CARACT RISTIQUES SPECIALES CONCUES POUR PROTEGER DES RAYONS X ET TIAL THAT DES DANGERS SECOUSSES LECTRIQUES E N CAS D BESOIN CRITICAL SIDES PIECES DE CETTE SYMBOLE MARQUE DOIVENT ETRE REMPLACE N UTILISEZ QUE DES PIECES SP CIFI ES PAR LE HANUFACTURIER 484 309A CHECK BETWEEN 18901 E AND GROUND 12V TROUBLESHOOTING GUIDE VIDEO IS OK BUT DISPLAY SIZE IS SMALL AND WAVY 0008 SMALL TR902 TR903 D905 gt TR901AND POWER REG CIRCUJT TROUBLE IM HORIZONTAL CIRCUIT D702 D703 C710 C709 TR701 C712 0704 0705 0706 C713 C714 C715 ABOVE 14V TROUBLE IN 701 C705 R707 0701 R706 R705 16701 TROUBLE IM FBT CR706 R712 LEAD H1 LEAD 1 V2 CHECK CRT G2 VOLTAGE 450V 2 CHECK CRT HEATER VOLTAGE 12V ABOVE 55 TROUBLE IM TR303 TR304 8311 8309
7. Goldstar MONOCHROME MONITOR SERVICE MANUAL BEFORE SERVICING THE CHASSIS READ THE SAFETY Ly GoldStar FEATURES e 2000 display characters in a 8 x 8 dot format e 18 MHz bandwidth medium class composite signal input e This monitor is compatible with a variety of home and personal computers CONTROLS LOCATION The MBM 2105G A monochrome monitor uses a RCA jack connector The input signal is input through the RCA jack connector The input signal is based on the composite level Figure 2 shows the monitor controls on the front and rear panels Power Indicator Contrast Brightness Power Video In H Position H Hold V Sue Power Cord Figure 2 Monitor Controls NOTE Monitor cabinet not used on 6300T Models 9 POWER PUSH ON Turn on the monitor by pressing the power switch The power indicator lights when the power is ON Always turn on the monitor before you turn on the computer To turn the power OFF just press this switch again e Brightness Turn this knob clockwise to increase brightness e Contrast Turn this knob clockwise to increase contrast e V Size Turn this knob to adjust the vertical size of the picture e H Hold Turn this knob to stop horizontal rolling of the picture H Position Turn this knob clockwise to move the center of the picture to the right turn the knob counterclockwise to move the center of the picture to the left H Size
8. T Models A B C gt REPLACEMENT PARTS LIST MECHANICAL PARTS no pant no REMARK 1 300738 cabinet 887 2 436552A METAL EARTH 3 234434 HOLDERLEO 4 EENE 5 YP 430 606 METAL POWER FIXING 341 439 HOLDER POWER 440 591 KNOB CONTROL 303928A COVER PCB SHIELD CASE REPLACEMENT PARTS LIST CAUTION Components identified by the symbols the PARTS LIST and on the SCHEMATIC DIAGRAM have special characteristics important to safety Do not degrade the safety of the set through improper servicing ABBREVIATIONS Capacitors CC Ceramic CE Chemical CK Ceramic Hi K BP Bipolar CQ Mylar PE Polyester PP Polypropylene Resistors RD Carbon Film RS Metal Oxide Film All CC and Capacitors are 5 50 Volts and all resistor 5 1 8W unless otherwise noted S Recommended Service Parts R Replacement Service Parts RESISTOR RD 1 8W 820 ohm RD 1 8W 47K ohm RD 1 8W 15K ohm RD 1 8W 33K ohm RD 1 8W 10K RD 1 8W 100K ohm RD 1 8VV 6 8K ohm RD 1 8W 33K ohm RD 1 8W 15K ohm RD 1 8W 1 8K ohm RD 1 8W 6 8k ohm RD 1 8W 2 2K ohm RD 1 8W 75K ohm RWR 7W 18 ohm RD 1 8W 390 ohm RD 1 8W 560 ohm RD 1 8W 560 ohm VARIABLE 500B SEMIFIX SR 29R 2208 SEMIFIX SR 29R 1KB SEMIFIX SR 29R 4 7KB SEMIFIX 5 19R 100KB
9. TR302 19 0045 KTA562 TR303 2N3904 KTC2229 Y 19 0053 19 0052 19 0051 19 0050 19 0049 19 0048 19 0047 TR304 19 0044 TR601 KTC2240 GR A TR701 BU806
10. kwise To increase the amount of raster shift move the two tabs which project from the device farther apart if raster is tilted an angle it may be straightened by loosening the deflection yoke clamp and rotating the deflection yoke BLOCK DIAGRAM Video Input TEA 2037A Power Trans Video Output TR303 TR304 V Output H Output TR701 Power 4 12V REG SCHEMAT CONTRAST pd VR301 5008 1 C305 100 16 17 KTAS62 0 Y KTA 015 07Y 0 a 312 83 12 HV OEFL C603 POWER REGULATOR MM C901 C904 0 0047 50x4 R904 15 0 WI YR901 KTD880 0 Y 4 gt 0901 0904 INS392GP 4 amp 50 315 750 VDE SEMKO 3 2 1V A 4 E NOTES 1 RESISTORS ARE SHOWN IN OHMS 4 IMPORTANT SAFETY NOTICE K 1 000 3M4z1000 000 tHe NSYMBOL MARK or THIS SCHEMATIC DIAGRAM INCOF 2 CAPACITORS ARE SHOWN FEATURES IMPORTANT FOR PROTECTION FROM X RADIA IN OTHERWISE NOTED ELECTRICAL SHOCK HAZARDS WHEN SERVICING IT IS 1 3 RESISTORS 5X ONLY MANUFACTURER S SPECIFIED PARTS BE USED f TOLERANCE UNLESS OTHERWISE NOTED COMPONENTS IN THE ASYMBOL MARK OF THE SCHE DIAGRAM 155 30 X0 0UT 310K GB3 GREEN YKGBA ALAMBER 12K 2 SYKGBUBLACK WHITE TR304 2 KTC2229 0 Y 310468 9 YELLOWISH GREEN 31 amp K 1
11. ltage is produced at the base of TR903 and is coupled directly to the base of the error amplifier TR902 This correction voltage is then passed from the emitter of TR902 directly 10 the base of TR901 and voltage regulation is then accomplished R316 L301 126 20 4 7uH 10 3 C308 2 2UF 100V TO CRT CATHODE 330 C306 120P R313 47 Figure 3 Video Amplifier Vertical F B Vetical Frame Vcc 1 Oscillator VCC 2 Vcc 2 Generator Frame Power Fly Back Oscillator Generator Vertical Phase Detector Line Fly Back Phase Horizontal Input Detector Oscillator Figure 4 BLOCK DIAGRAM OF THE TEA 2037A 3 COMPOSITE VIDEO INPUT AND HORIZONTAL VERTICAL DEFLECTION 3 VIDEO INPUT PIN 15 3 8 LINE H OSCILLATOR PIN 9 The detection level for negative sync pulse at the The line oscillator is of the type which charges and sync separation input pin 15 is set at 1 6V When discharges a capacitor since a perfectly linear the voltage at emitter of the Transistor pin 15 is sawtooth wave form is not required above 1 6 the transistor is cut off Voltage The free running frequency is dependent on 5 lower than 1 6V enables the transistor to conduct R705 and VR702 and is governed by this expres and the internal circuitry is enabled for sion To 085 x C705 x R705 where To is the line synchronization function oscillator free running frequency 3 4 FRAME V OSCILLATOR PIN 9 VR Oscillator thresholds
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