Text preview for : M134A_TroubleShooting.pdf part of RCA full Schematics and parts manual with trouble shooting guide.
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Fuse Blown
Figure 1
Fuse Blown
Is IC801 PIN1 shorted to ground?
No
Is DB801 OK?
No
Replace DB801
Yes
Yes
Check / Replace IC801
Check the components such as C801, C802, C806, C807, C815, R801, etc.
No raster Voltage
abnormal + B
Figure 2
No Raster, Abnormal +B
Is + B, +13V, +12V, +9V shorted to ground?
Check IC201, IC202 Yes and their peripheral components Yes
Check Q820 Q821, Q823
Q822,Q825etc.
No Check/Replace shorted component
Yes Check IC801 and their peripheral components Yes Check T802 etc.
Figure 3
No Raster, +B OK
No raster, +B ok
Is +9V, +5V Shorted to ground? NO Check/Replace short
Y
Is
there
an
output waveform Pin13of IC101? No
Yes
Waveform at C of Q411? No Is the drive circuit ok? No Check\replace the drive circuit
Yes
Is R461 ok? Yes Increase VG2
No
Replace R461
Is Pin2 of IC101 low voltage level? Yes Is B of Q202 low voltage level? Yes No No
Yes Replace FBT
NG
Is both +14V and -14V ok? Yes
Check horizontal scan circuit, such as C412, C413, C419, etc
Is the waveform ok at Pin 6 of IC301? No Check vertical scan circuit
Figure 4
No picture, dense noise dots
No Picture dense noise dots
Is the signal at Pin41, Pin42 of Is the antenna feed line or the adapter broken or unsoldered? Yes Fix the antenna fault No IC101 ok? No Is the signal at IF pin of the tuner ok? No Is the signal at Pin SCL, SDA of tuner ok? No Check signal at P5, P57, P58, P59, and P60 of IC101 and replace the abnormal related circuits Yes Check EEPROM Yes Is the supply voltage of tuner ok? No Check/Replace IC201, IC202, D101. Yes Check/Replace Tuner Yes Yes Check/Replace IC101 Check the related circuits of Q101,
Figure 5
Symptom: raster ok, no picture, no sound, sparse noise dots
Sparse Noise
Apply the lead of a multimeter at R X 1 K , connect one probe to GND, use another to touch Pin42 of IC101. Are there interference particles screen? Yes Unsolder a pin of C107, apply the lead of multimeter at R X 1 K, connect the red probe + to GND, use the black probe - to touch B of Q101. Are there interference particles flashing on the screen? No Bridge a capacitor of 1000pF between the input and output of Z141. Apply the lead of multimeter at R X 1 K , connect the red probe + to GND, and use the black probe - to touch B of Q101 Are there interference particles flashing on the screen No No Does the IF pre-amplifier work normally? flashing on the No Is the voltage at Pin29, P36 of IC101 ok? No Check and repair the +9V power supply
Yes
Yes Replace Z141 (SAW)
Yes
Check
&
Replace the Tuner
repair the IF pre-amplifier circuit
No sound
Figure 6 No Sound
No
Is the speaker ok? Yes
Replace the speaker
Replace Apply the lead of a multimeter at RX1K connect one probe to GND, use another to touch Pin4, Pin12 of IC602, Is there interference noise from the speaker. No Check power Yes supply of IC602 Is it mute at P6 of IC602? Yes Check/Replace Q601, Q602 Yes Is the waveform at Pin47 of IC1001 ok? Check/Replace the power supply of IC1001. RESET Then and Q603 etc. No IC602
Yes
NG
Is the BUS ok?
No
Check IC101 and the related circuits
No Check/Replace Q203, X202 etc. NG Is the waveform at Pin30 of IC101 ok?
No
Replace IC101
Figure 7 No Picture
TV&AV haven't Picture Ok Check P25, P49 Is RGB signal ok? No Check Pin20, Yes of IC101 and the NG related circuit Pin24 of IC101 Is +9V, +200V ok? Yes Check Q501~Q506 Yes Check R516 ~ R521 etc.
Replace IC101
No TV Picture. hasn't Picture. Is the waveform at Pin12, Pin14 of IC901 ok? No No Picture Check Q901 ~ Replace IC901 Yes Is the logic at P9, P10 of IC901 ok? has AV Check P13 of IC901 NG
Check
Q917
and
Video path Circuit
Check P1 of IC101, No P4 of IC1001 and the related circuit
Yes
Q904 path circuit
Replace IC901 Is the waveform at P15 of IC901 AV hasn't Picture. has ok? Yes Is the logic at P9, P10 of No No Is the waveform at P30 of IC101 ok? Yes No Check related Check Q203, Q204 and related circuits page Figure 5. IC101 and circuit. IC901 ok? Yes Check P1 of IC101, P4 of IC1001 and the related circuit
Picture. TV
Reference the previous
Figure 8
No Vertical Scanning
Yes
Is both +14V and -14V ok?
No
Yes
Is the signal at P1 of IC301 ok?
No
Check/Replace
R431,
R433, D431, D432 etc No Check signal at P16 of IC101 Check/Replace R311, R313. R245, Yes
Check/Replace IC301
Check/Replace IC101
Figure 9
Symptom: Tuning Control not working Press STANBY key on R/C. Can the off? Yes Does the channel number display Check at Pin60, Pin61 of IC101 the on the screen? Yes Start autosearch. Is the BUS ok? Yes After auto-search, Can the searched program be memorized? No No waveform Yes No No TV be turned on and No
No Tuning
IC101.
Check the power supply of Are there H & V flyback pulses at Pin12 of IC101 Yes Check/Replace IC101 No Check R314, R315, R316, C311, D303
Check/Repair +33V No power supply Check/Replace Is Yes there a No the tuner
Is the +33V/+5V A power supply ok?
short
circuit Check/Repair the integration circuit
around the integration circuit? Yes
Is there sync pulse at P62 of IC101? No Yes
Is the voltage at P8 of IC001ok? No Check/Repair +5V
Yes
Replace IC001
Is
there
sync
power supply. No
pulse at B of Q003?
Yes Replace Q003
Check Q915, Q916 and the related circuits
Figure 10
Tuning Control not working
Is there any change on the voltage level at P64 of IC101?
No
Check the remote control receiver and transmitter. Yes Is the VDD(+5V) at P9 and P55 of IC101 ok? No Check Q007 etc.
Yes Is there a 8MHz/5Vp-p sine wave oscillator at P6 of IC101? Yes No Is the voltage at P5 of IC101 ok? Yes Briefly short P5 of IC101 to GND. Does the IC101 work? No Check/Replace IC101 No Replace the disabled components No Are C031, C032 and X001 ok? Yes
Yes Check/Repair circuit. the reset