Lexmark 4049LMO Service Manual - Page 43

4049-XXX the LVPS voltages are correct. Turn the power back off and, one at a time, reconnect the engine board cables, powering on in between each connection and checking the voltages. The connection which causes the voltages to be wrong indicates which component is bad. Repair or replace the failing component or cable as necessary. Duplex The duplex unit should home - the front shafts should turn and the input deflector should move - immediately when you install the duplex unit with the printer already powered on, or just before the [Ready] screen is displayed when you POR the printer with the duplex unit installed. This means the duplex unit and the printer are communicating and thus the printer engine board, duplex unit system board, and the cables between them are all good. If the duplex unit does not home immediately but homes after 5 or 6 seconds, the duplex unit is receiving +34 VDC from the printer but is not communicating with the printer. The duplex unit homes on its own as a signal that it is functional. If the duplex unit does not home at all, it is either damaged or is not receiving +34 VDC from the printer. To check the connection from the printer engine board to the duplex system board, remove the printer RIP Board. Remove the duplex top cover and table cover, and reinstall the duplex unit. Engine board J32 should have continuity with the duplex system board J5-1, J3-3 with J5-2, and so on. With power on, you should have the following voltages: Connector Engine Board Duplex System Board J3-3 J3-5 J3-7 J5-2 J5-4 J5-6 Voltage to Ground +34 VDC +5 VDC +5 VDC +34 VDC +5 VDC +5 VDC Diagnostic Information 2-16