background image

2

IMPORTANT SERVICE SAFETY PRECAUTION

Ë

Service work should be performed only by qualified service technicians who are thoroughly
familiar with all safety checks and the servicing guidelines which follow:

4A 125V

SERVICING OF HIGH VOLTAGE SYSTEM
AND PICTURE TUBE

When servicing the high voltage system,
remove the static charge by connecting a
10k ohm resistor in series with an insulated
wire (such as a test probe) between the pic-
ture tube ground and the anode lead. (AC
line cord should be disconnected from AC
outlet.)

1. Picture tube in this receiver employs integral

implosion protection.

2. Replace with tube of the same type number for

continued safety.

3. Do not lift picture tube by the neck.
4. Handle the picture tube only when wearing

shatterproof goggles and after discharging the high
voltage anode completely.

X-RADIATION AND HIGH VOLTAGE LIMITS

1. Be sure all service personnel are aware of the

procedures and instructions covering X-radiation.
The only potential source of X-ray in current solid
state TV receivers is the picture tube. However, the
picture tube does not emit measurable X-Ray
radiation, if the high voltage is as specified in the
"High Voltage Check" instructions.
It is only when high voltage is excessive that X-
radiation is capable of penetrating the shell of the
picture tube including the lead in the glass material.
The important precaution is to keep the high voltage
below the maximum level specified.

2. It is essential that servicemen have available at all

times an accurate high voltage meter.
The calibration of this meter should be checked
periodically.

3. High voltage should always be kept at the rated value

-no higher. Operation at higher voltages may cause
a failure of the picture tube or high voltage circuitry
and;also, under certain conditions, may produce
radiation in exceeding of desirable levels.

4. When the high voltage regulator is operating properly

there is no possibility of an X-radiation problem.
Every time a color chassis is serviced, the brightness
should be tested while monitoring the high voltage
with a meter to be certain that the high voltage does
not exceed the specified value and that it is regulating
correctly.

5. Do not use a picture tube other than that specified

or make unrecommended circuit modifications to the
high voltage circuitry.

6. When troubleshooting and taking test measurements

on a receiver with excessive high voltage, avoid being
unnecessarily close to the receiver.
Do not operate the receiver longer than is necessary
to locate the cause of excessive voltage.

WARNING

1. For continued safety, no modification of any circuit

should be attempted.

2. Disconnect AC power before servicing.
3. Semiconductor heat sinks are potential shock

hazards when the chassis is operating.

4. The chassis in this receiver has two ground systems

which are separated by insulating material. The non-
isolated (hot) ground system is for the B+ voltage
regulator circuit and the horizontal output circuit. The
isolated ground system is for the low B+ DC voltages
and the secondary circuit of the high voltage
transformer.
To prevent electrical shock use an isolation
transformer between the line cord and power
receptacle, when servicing this chassis.

CAUTION: FOR CONTINUED
PROTECTION AGAINST A
RISK OF FIRE, REPLACE
ONLY WITH SAME TYPE 4A-
125V FUSE.

20MR10M

Summary of Contents for 20MR10M

Page 1: ...er sales service only The contents are subject to change without notice CONTENTS SERVICE MANUAL POWER INPUT 120 V AC 60 Hz POWER RATING 69 W PICTURE SIZE 1 194cm2 185sq inch CONVERGENCE Magnetic SWEEP DEFLECTION Magnetic FOCUS Hi Bi Potential Electrostatic INTERMEDIATE FREQUENCIES Picture IF Carrier Frequency 45 75 MHz Sound IF Carrier Frequency 41 25 MHz Color Sub Carrier Frequency 42 17 MHz Nomi...

Page 2: ...eter should be checked periodically 3 High voltage should always be kept at the rated value no higher Operation at higher voltages may cause a failure of the picture tube or high voltage circuitry and also under certain conditions may produce radiation in exceeding of desirable levels 4 When the high voltage regulator is operating properly there is no possibility of an X radiation problem Every ti...

Page 3: ... mechanical insulators and etc 3 To be sure that no shock hazard exists check for leakage current in the following manner Plug the AC cord directly into a 120 volt AC outlet Do not use an isolation transformer for this test Using two clip leads connect a 1 5k ohm 10 watt resistor paralleled by a 0 15mF capacitor in series with all exposed metal cabinet parts and a known earth ground such as electr...

Page 4: ...4 LOCATION OF USER S CONTROL 20MR10M ...

Page 5: ... the horizontal oscillator does not stop in step 5 the circuit must be repaired before the set is returned to the customer HIGH VOLTAGE CHECK High voltage is not adjustable but must be checked to verify that the receiver is operating within safe and efficient design limitations as specified checks should be as follows 1 Connect an accurate high voltage meter between ground and anode of picture tub...

Page 6: ...Use the reset function in the video adjustment menu to ensure customer controls are in their proper reset position 2 Service number selection Once in the service mode press the Ch up or Ch down button on the remote controller or at the set The service adjustment number will vary in increments of one from S01 to OP Select the item you wish to adjust 3 Data number selection Press the Vol up or down ...

Page 7: ...TE POINT ADJ MODE W P RED OFFSET HIGH OFFSET BLUE TONE DRI R HI W P GREEN OFFSET HIGH OFFSET BLUE TONE DRI G HI W P BLUE OFFSET HIGH OFFSET BLUE TONE DRI B HI W P RED MH STD DRI R MH W P GREEN MH STD DRI G MH W P BLUE MH STD DRI B MH W P RED OFFSET ML OFFSET RED TONE DRI R ML W P GREEN OFFSET ML OFFSET RED TONE DRI G ML W P BLUE OFFSET ML OFFSET RED TONE DRI B ML W P RED OFFSET LOW DRI R LO W P GR...

Page 8: ... SOURCE CHANGE VMC HOTEL MODE HTL GAIN FM DEMODULATOR BTSC CHARGE PUMP CP FM WINDOW SELECTION FMWS SOUND MUTE BIT 0 SM0 SOUND MUTE BIT 1 SM1 IF AGC SPEED BIT 0 AGC0 IF AGC SPEED BIT 1 AGC1 PHI 1 TIME CONSTANT FOR FE FOA FE PHI 1 TIME CONSTANT FOR FE FOB FE PHI 1 TIME CONSTANT FOR AV FOA AV PHI 1 TIME CONSTANT FOR AV FOB AV FORCED SLICING LEVEL FOR VERTICAL SYNC FSL SYNCHRONISATION OF OSD TEXT DISP...

Page 9: ...SS 0 63 32 FIX must be 27 HTL VOL MAX HOTEL VOLUME 0 63 32 FIX HTL PRG HOTEL PROGRAM NO 0 125 or 125 for none 255 FIX BB CON BLUE BACK CONTRAST 0 15 10 FIX must be 5 RGB OSD GRB REFERENCE 0 15 15 FIX must be 5 CUT R BLACK LEVEL OFFSET R 0 63 32 ADJ CUT G BLACK LEVEL OFFSET G 0 63 32 ADJ CDL CATHODE DRIVE LEVEL 0 15 0 FIX must be 4 DL TV Y D TIME TV YD 0 15 12 FIX must be 2 DL AV Y D TIME AV YD 0 1...

Page 10: ... FAO FIXED AUDIO OUT 0 disable or1 enable 0 FIX VIEW TM VIEW TIMER 0 disable or1 enable 1 FIX must be 1 FRENCH FRENCH LANGUAGE 0 disable or1 enable 0 FIX must be 1 EZ SETUP EZ SETUP AUTOPRESET 0 AUTOPRESET or 1 FIX must be 0 1 EZ SETUP W TEMP WHITE TEMP OR FAVORITE COLOR 0 FC or 1 WT 0 FIX AV AV ENABLED OR DISABLED 0 without ext source or 0 FIX must be 1 1 with external source AV2 AV2 ENABLED OR D...

Page 11: ...aster screen cotrol until the raster darkens to the point where raster is barely seen 7 Adjust the service adjustments S11 red S12 green and S13 blue to obtain a good grey scale with normal whites at low brightness level 8 Select the service adjustment S19 and reset data to 00 Select the service adjustment S03 and reset data to obtain normal color level 9 Remove digital voltmeter and reset the mas...

Page 12: ... measured with 1000µ V B W or Color signal WAVEFORM MEASUREMENT CONDITIONS 1 Photographs taken on a standard gated color bar signal the tint setting adjusted for proper color The wave shapes at the red green and blue cathodes of the picture tube depend on the tint color level and picture control 2 indicates waveform check points See chart waveforms are measured from point indicated to chassis grou...

Page 13: ...A B C D E F G H 10 9 8 7 6 5 4 3 2 1 SCHEMATIC DIAGRAM MAIN 1 Unit 13 20MR10M ...

Page 14: ...17 16 18 15 14 13 12 11 10 19 14 20MR10M ...

Page 15: ...6 5 4 3 2 1 A B C D E F G H SCHEMATIC DIAGRAM CRT Unit 15 20MR10M ...

Page 16: ... AB Q253 VS2SD601AR 1Y X 2SD601AR AA Q254 VS2SD601AR 1Y X 2SD601AR AA U Q601 VS2SC3207 1 X 2SC3207 AT AC Q603 VS2SC3198 G 1 X 2SC3198 G AB Q751 VS2SC3198 G 1 X 2SC3198 G AB Q752 VS2SC3198 G 1 X 2SC3198 G AB Q801 VS2SB709AR 1Y X 2SB709AR AA Q802 VS2SB709AR 1Y X 2SB709AR AA VS2SD2586 1E X TRANSISTOR AG D201 RH EX0676GEZZY X Zener Diode 32V AB D302 VHD1SS119 1Y X Diode AA D331 RH DX0302CEZZY X Diode ...

Page 17: ...J X 0 056 50V Mylar AA C602 VCEA0A1HW475M X 4 7 50V EL AA C603 VCEA0A1HW105M X 1 50V EL AA C604 VCEA0A2EW106M X 10 250V EL AC C605 VCKYPA2HB102K X 1000p 500V Ceramic AA C606 VCFPVC2DB474J X 0 47 200V M Poly AC C607 VCFPVC3ZA772H X 7700p 1 5kV M Poly AC C608 VCKYPA2HB102K X 1000p 500V Ceramic AA C610 VCEA0A1CW108M X 1000 16V EL AC C611 VCEA0A1EW476M X 47 25V EL AA C612 VCEA0A1CW477M X 470 16V EL AB...

Page 18: ...de R607 VRD RM2HD270JY X 27 1 2W Carbon AA R609 VRD RA2BE154JY X 150k 1 8W Carbon AA R610 VRD RA2BE102GY X 1 0k 1 8W Carbon AA R611 VRD RA2BE102JY X 1k 1 8W Carbon AA R612 VRS CY1JF123JY X 12k 1 16W M Ox AA R613 VRS CY1JF103JY X 10k 1 16W M Ox AA R614 VRS RG2HC100J X 10 1 2W M Ox AB R615 VRS RG3DB682J X 6 8k 2W M Ox AB R616 VRN RL3ABR47J X 0 47 1W M Film AB R618 VRS RG3DB391J X 390 2W M Ox AB R619...

Page 19: ...B Q885 RH TX0124BMZZ X TX0124BM AB Q887 RH TX0124BMZZ X TX0124BM AB D881 VHD1SS244 1Y X Diode AA D882 VHD1SS244 1Y X Diode AA D883 VHD1SS244 1Y X Diode AA D884 VHD1SS119 1Y X Diode AA D885 VHD1SS119 1Y X Diode AA CAPACITORS EL Electrolytic M Poly Metalized Polypro Film Ref No Part No Description Code C871 VCCSCY1HL471JY X 470p 50V Ceramic AB C872 VCCSCY1HL471JY X 470p 50V Ceramic AB C873 VCCSCY1HL...

Page 20: ...abel AA SPAKCB958WJZZ X Packing Case AT SPAKP0102GJZZ X Lamifoam AE SPAKX0003GJZZ X Packing Foam AN SSAKA0101GJZZ X Plastic bag AB CABINET PARTS LOCATION CABINET PARTS Ref No Part No Description Code 1 CCABA0006WEH7 X CAB A ASSY BB 1 1 Not Available FRONT CABINET 1 2 GCOVA0003GJSA X R C COVER AM 1 3 HBDGB1001GJSB X BADGE AD 1 4 JBTN 0003GJSD X BUTTON Button Power AF Vol up down CH up down 2 GCABB0...

Page 21: ...f packing case Packing Case FRONT Buffer Material Wrapping Paper Polyethylene Bag Operation Manual Infrared R C Unit Batteries MARK Not replacement items Use 10 staples to fix the bottom side of packing case 20MR10M PACKING OF THE SET 21 ...

Page 22: ...his publication may be reproduced stored in a retrieval system or transmitted in any form or by any means electronic mechanical photocopying recording or otherwise without prior written permission of the publisher SHARP ELECTRONICA MEXICO S A DE C V Quality Reliability Control Center Blvd SHARP No 3510 Parque Industrial Rosarito Playas de Rosarito México B C 22710 20MR10M ...

Reviews: