ZR70 MC A, ZR65 MC A, ZR60 ACHAPTER 3. INFORMATION FOR REPAIR · SERVICE HINTS3-176. Trouble ShootingTo detect the failure part for repair, if any, use the following hints and check points.6-1 Power SupplyWhen 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 P.C.B. → MODE microcomputer starts up. → MODE microcomputeroutputs VCR ON “H” signal. → PWM driver starts up and turns on each power supply. → Establishes communication with the FRmicrocomputer. → FR microcomputer initializes recorder mechanical chassis. → After initialized, the MODE MI-COM is brought intothe 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 MODE MI-COM is accepted, VCR ON “H” is output. → The PWM driver is started toturn on various power supplies. → The FR MI-COM is started to control the system.1) Key InputsCheck the key inputs at Power Switch in the SERVICE mode.2) Check of microcomputer-to-microcomputer communicationIf the microcomputer-to-microcomputer communication line is normal, the version number of each microcomputer can be indi-cated in the service mode. Otherwise, the communication line or microcomputer may be faulty.3) Error in Mechanism (P. 3-8)If any error is occurred by mechanism trouble at initializing, the error can be detected.At this state, the power can be turned on, but the unit enters “ERROR STOP” state. In this case, check the error data in theSERVICE mode.4) VCR ON “H”, CAM ON “H” (control signal from MODE microcomputer) OutputsCheck the output of control signal by the LANC remote controller.5) Fuses on the POWER SUPPLY P.C.B.Check the continuity of the fuses FU3201, 3202, 3203, 3204, 3205 and 1801 on the MAIN P.C.B. In case of NG, replace the fuseand check the power consumption.6) Replace the MAIN P.C.B. with a service part and check the operation.
