Read Sharp LC-19A1E (serv.man4) Service Manual online
LC-19A1E-BK/WH
4 – 3
Power supply (troubleshooting): A power supply does not come to each main circuit/IC. (2)
The power supply of a VIDEO system/IC801 (DVP) 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 B1.5V supplied to pin (D12) of IC801 (DVP)?
NO
Check whether POWER-CTL signal is input to pin (4) of IC705
(REG). Or check whether B1.5V is output from pin (6) of IC705.
(REG). Or check whether B1.5V is output from pin (6) of IC705.
YES
YES
Is B12V supplied to pin (5) of IC705 (REG)?
YES
Is B3.3V supplied to pin (R19) (D5) of IC801 (DVP)?
Check soldering of IC801 or check whether B3.3V is
output from pin (3) of IC703 (REG).
output from pin (3) of IC703 (REG).
YES
NO
Is B3.3V supplied to pin (1) (19) of IC9201 (RSDS-TR)?
NO
Check soldering of IC9201 or check
whether B3.3V is output from pin (3) of
IC703 (REG).
whether B3.3V is output from pin (3) of
IC703 (REG).
NO
Check the soldering of IC703 or exchange it.
NO
Is B12V supplied to pin (2) of IC703 (REG)?
YES
Is the POWER-CTL signal input to pin (3) of Q701 (SW)?
NO
Is B12V output from pin (6) of Q701 (SW)?
NO
YES
Check between pin (3) of Q701 (SW) to pin (29) of IC2002 (SUB-
MICON).
MICON).
Is UR12V input into pin (4) of Q701 (SW)?
NO
Check the soldering of Q701 (SW) or exchange it.
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