SECTION3 ELECTRICAL

ELECTRICAL TROUBLESHOOTING GUIDE

5.SYSTEM/KEY CIRCUIT

(1) AUTO STOP

Auto Stop

YES

Does SW waveform appear at IC501 NO

pin23?

YES

Check Drum motor signal

 

Does T/up reel pulse appear

NO

Does T/up reel pulse appear

 

NO

 

Is there 5.3V at RS501?

 

 

 

 

 

 

 

 

 

 

at IC501 Pin27?

 

 

at Q514 Base terminal?

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

YES

 

 

 

 

 

YES

 

 

 

YES

 

 

NO

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Replace T/up reel sensor of deck

 

 

 

 

 

Check DP06, LP03

 

 

Replace IC501

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Check power circuit

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(2) No cassette tape loading

No cassette tape loading

YES

Is there REG. 12V at PMCQ1

Pin8?

YES

Does 'H' signal appear at IC501

Pin62 while inserting CST?

YES

NO

Check power circuit L104.

NO

Is there 5.3V at IC501 Pin73?

YES

 

 

NO

 

 

 

 

Check CST SW and peripheral circuit

Check power circuit

Check D106, L103.

NO

Check Deck mechanism

Check IC501 Pin7, 8, 9, 10

*Caution : Auto stop can occur because Grease or Oil is dried up

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LG Electronics TL-AT130M service manual SYSTEM/KEY Circuit Auto Stop, No cassette tape loading