4-64 WorkCentre C2424 Service Manual■ Exit Module J680■ Heater Relay Control J950 (no cable)c. Retest the resistance of the I/O board. If the resistance is still less than 1Kohm, replace the I/O board, reinstall all cables and retest system.d. If the I/O board resistance is OK, plug in the I/O board connectors one at atime and retest the resistance. If the resistance drops below 1K ohm, intentifywhich connector you just reattached. The problem will be with thecomponent that was just reconnected or the wire harness is defective.Replace the suspected component and test.7. Short circuit on 3.3 V power supply within the printhead.a. REQUIRED: Follow all procedures from 'Short circuit on 3.3 V powersupply within the electronics module' before proceding. The followingprocedure relies on a working electronics module to determine if theprinthead is causing a short circuit.b. With power cord connected, touch the metal electronics module to dischargeany static electricity. ESD damage to the system may occur if staticelectricity is discharged to system electronics.c. Turn off system and wait 30 seconds for power supply capacitors todischarge. Damage to circuits within the electronics module may occur if thepower supply capacitors are not allowed to fully discharge.d. Plug in the printhead interface connector ('J130) to the electronics module.e. Power on the system.f. If the PE and PS indicators do not flash, the short is on the printhead.Replace the printhead and retest the system. Skip the rest of Step 8 if the PEand PS indicators flash because the problem is elsewhere in the system.g. Carefully test the system to ensure damage to the electronics module did notoccur due to the shorted printhead.System Energy Star Mode Troubleshooting1. Model not configured as an E NERGY STAR model.a. Use the control panel to enable Energy Star mode. Many systems are notshipped as Energy Star compliant and don't have the power saving modeenabled by default.2. Electronics module failure.a. REQUIRED: Ensure you have performed Step 1.b. With power cord connected, touch the metal electronics module to dischargeany static electricity.c. Turn off system and wait 30 seconds for power supply capacitors todischarge.d. Unplug power cord and remove system's covers.e. Replace the electronics module.f. Plug in all cables removed during service.g. Trace through all service steps performed to reattach any cables that wereunplugged during troubleshooting.
