According to the fault phenomena analysis, could be the record part. First check the thermal head power supply voltage, electricity to copy, measured with a multimeter connectors CN404 of power supply unit (1) no + 24 v voltage output end. The (1) end of the measurement again another connector CN402 + 24 v voltage is normal. hcyservice manual download site
 hcyservice manual download site
Due to the thermal HEAD power supply voltage as the controlled power source, by + 24 v power supply circuit through a relay RLY401 output, coil by the main control circuit of relay output signal control HEAD ON. + 24 v power supply circuit output voltage in the normal and sensible heat power supply voltage is not normal, relay not off. Check CN402 1 foot (the HEAD) ON signal when the copy is transformed into high level and working properly. hcyservice manual download site
 hcyservice manual download site
 hcyservice manual download site
As shown, after measuring Q404 output into the copy state remained high voltage constant, drive 0404 damage. After the replacement drive Q404, boot test, when receiving record copy is normal, troubleshooting.hcyservice manual download site