Canon LV-7545U, Service Manual

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2) Power/lamp drive signal error
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Power start signal (FAN_DRIVE_SW) error
The FAN_SW signal is output from pin 137 of IC801, passes through Q4807, is sent
to the power switching circuit. This signal drives the power oscillation circuit of the
power supply unit and the cooling fan power circuit of the power supply circuit.
FAN_DRIVE/FAN_SW is high when power is on.
Check FAN_DRIVE, FAN_SW signal, switching circuit Q6623, Q6624, Q6604,
IC6604, IC6602, IC6603, IC6606 and its peripheral circuits.
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Fan drive signal (IC_RESET) error
The IC_RESET signal is output from pin 2 of IC801, sent to Q6616, Q6612, and
Q6613 of the sub power supply unit. They switch power lines 9V, 9VA, 15.7V, 15VP
and 3.4V.
IC_RESET is high when power is on.
Check the IC_RESET signal, IC801, drive transistor, diode, IC, Q6616, Q6617,
Q6612, Q6611, Q6613, Q6626, Q6602, Q6628, IC6608, IC6618, IC6607, IC6601,
IC6616, and its peripheral circuits.
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Power supply drive signal (LAMP_SW) error
The LAMP_SW signal is output from pin 138 of IC801, passes through K8L 3 pin of
the main board, and drives the lamp ballast unit.
LAM_SW is high when power is on.
Check the LAMP_SW signal, IC801 and peripheral circuits.
3) Power supply circuit error
●
Primary side power erro
Check line filter L601, L602, D604, Q601, DS601, L611, IC651 and D632.
●
Secondary side power error
Check D681, D682, D683 and IC681.
Part 4: Troubleshooting
4-2