HP LaserJet 4100 Series printer

AC/DC power distribution

In this circuit, the AC power input from the power receptacle is converted into DC power. The DC power is supplied to the loads.

The AC power is supplied to the low-voltage power-supply circuit in the engine controller board when the power switch (SW1) is turned on.

The AC power is converted into +24 VDC, +5 VDC, and +3.3 VDC in the circuit. The +24 VDC is supplied to the main motor, scanner motor, solenoids, clutches, and to the high-voltage power-supply circuit. The +5 VDC is supplied to the laser and formatter, while +3.3 VDC is supplied to the sensors and ICs on the engine controller board.

The +24 VDC is divided into +24 VA, which is constantly supplied from the low-voltage power supply circuit, and +24 VB, which is interrupted

when the interlock switch (SW101) is turned off by opening the top 3 cover. The +24 VB is supplied to the high-voltage power-supply circuit

on the engine controller board and relay (RL102). It also functions as a door-open detection signal (/DOPEN), so that the CPU detects an open door.

EN

AC and DC power distribution 137