CHAPTER 13 TROUBLESHOOTING13-134 COPYRIGHT © 1999 CANON INC. CANON CLC1120/1130/1150 REV.0 MAR. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)42 The scanning lamp fails to turn on.CauseScanning lampScanner thermalswitch (TP1, TP6)Scanning lamp(open circuit)Lamp regulatorcover currentAC power supplyActionMount the lampproperly.Replace the thermalswitch.· If the lamp has turnedon wrongly, thethermal switch may bemounted wrongly orthe cooling fan mayhave failed to turn on.Be sure to find out thecause.Check the wiring fromJ11 to the lamp; ifnormal, replace thelamp.Replace the lampregulator.· Check to make surethat the lamp and theharness do not have ashort circuit.See "AC power isabsent."ChecksTurn off the power switch, anddisconnect the power plug. Is thelamp mounted properly?Check both terminals of thescanner thermal switch. Is thereelectrical continuity?Disconnect J11 (3-pin) of the lampregulator, and set the meter rangeto 1 kΩ. Dose the index swingwhen the probe is connected to J11on the harness side?Is there electrical continuity on thefuse inside the lamp regulator?Connect J11, and disconnect J9 (4-pin). Connect the connector, andturn on the power. Set the meterrange to 300 VAC, and measure thevoltage between J9-1 and -4 on theharness side. Is the rated AC powerpresent?Step12345Yes/NoNONONONONO
