Read Sharp LC-19D1EBK (serv.man5) Service Manual online
LC-19D1E/S-BK/WH
4 – 3
Power supply (troubleshooting): A power supply does not come to each main circuit or IC. (3)
The power supply of a AUDIO system does not operate.
Checklist:
1) The check of the front page POW (1) is completed.
• • • UR12V is output to SC1204 (MAIN-PCB).
(If UR12V is not output, confirm the POW(1) again and repair.)
2) Check that BU3.3V is supplied to IC2002 (SUB-MICON), and the AC-CTL signal H is output from 35pin within a MAIN board.
(If BU3.3V is not supplied, check IC2004 (BU3.3V-REG) and a periferal circuit.)
3) Refer to attached sheet Power-Block diagram.
Is UR12V supplied to pin(47)(46)(39)(38) of IC303(P-AMP) ?
NO
Check the UR12V line from pin (13-15) of SC1204.
YES
Is B3.3V supplied to pin(13)(26) of IC302(A-CODEC) ?
NO
Check the soldering of IC302 or Is B3.3V output from pin(3) of
IC703(REG)?
IC703(REG)?
YES
NO
Is UR12V supplied to pin(7) of IC703(REG) ?
Check the soldering of IC703(REG) or exchange it.
Check the soldering of IC703(REG) or exchange it.
Is B9V supplied to pin(14) of IC301(A-SEL) ?
NO
Is B3.3V output from pin(5) of IC702(REG)?
YES
NO
Check the soldering of IC301(A-SEL) or exchange it.
Check the soldering of IC702(REG) or exchange it
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