Troubleshooting; Power Supply Malfunction - Canon DC10 E Service Manual

2. Troubleshooting

To detect the defective parts for repair, if any, use the following hints and check points.

2-1 Power Supply Malfunction

<Hints>
When the power source is attached, the unit enters the standby mode in the following sequences.
Main power is connected. → UNREG is supplied to the MAIN PCB → SUB MI-COM starts up. → CCM MI-COM starts up. → SUB
MI-COM outputs VCR ON "H" signal. → PWM driver starts up and turns on each power supply. → Establishes communication with
the BACK END → The CCM MI-COM is brought into standby status with the VCR ON changed to VCR Low.
After that, the power supply is turned ON by the following procedures.
Power supply mode switch operation → After received by MODE MI-COM, VCR ON "H" is output. → The PWM driver is starts to
turns on various power supplies. → The MI-COM in the BACK END is started up to control the system.
<Check Points>
1) Key Input
Check the key input at Power Switch in service mode.
2) Check of microcomputer-to-microcomputer communication
If the microcomputer-to-microcomputer communication line is normal, the version number of each microcomputer will be dis-
played in service mode. Otherwise, the communication line or microcomputer may be faulty.
3) Fuses on the power supply PCB
Check the continuity of the fuses FU3200, 3201, 3202, 3203, 3204, 3205 and 1800 on the MAIN PCB. If NG, replace the fuse and
check the power consumption. (FU3200 is for DC20 E only.)
4) Replace the MAIN PCB with a service part and check the operation.
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DC10 E, DC20 E
SERVICE HINTS