Epson LQ-570e - Unit Repairing of the Power Supply Board

EPSON LQ-570e/LQ-580 Revision C
T
roubleshooting
U
nit Repairing of the Power Supply Board
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3.3 Unit Repairing of the Power Supply Board
This section is necessary only for servicer persons who repair to the component level.
Servicers who perform only board replacement can ignore this section.
The table below lets you troubleshoot problems with the power supply board (C293PSB/
PSE). The table provides various symptoms, likely cases, and checkpoints. Checkpoints
include waveforms, resistance, and other value to be checked to evaluate the operation of
each component.
Table 3-1. Repair of the C293PSB/PSE
Symptom Condition Cause Check point Solution
Fuse F1 is blown Verify whether the fuse is blown or not. Replace the C293PSB/PSE board.
Transformer (T1) is open. Verify the coil of transformer by a multimeter. Replace the C293PSB/PSE board.
The printer does not operate at all. +35V line is defective. Switching FET (Q1) is defective.
Verify the waveform at drain of Q1.
Replace the C293PSB/PSE board.
Q2 or Q3 is defective.
Verify the waveform at corrector of Q2 or Q3 .
Replace the C293PSB/PSE board.