Epson LQ-570e - Unit Repairing of the MAIN Board

EPSON LQ-570e/LQ-580 Revision C
T
roubleshooting
U
nit Repairing of the MAIN Board
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3.4 Unit Repairing of the MAIN Board
This section is necessary only for servicers 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 main board (C293MAIN). 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 3-2. Repair of the C293PSB/PSE
Symptom Condition Cause Check point Solution
The printer does not operate at all. The CPU does not operate.
The reset circuit is not
operational.
Verify the voltage waveforms for the +5VDC line
(IC6, pin 7) and for the reset signal (IC6, pin 5).
Replace the C293MAIN board.
Selection control ROM is
abnormal.
Verify the signal at pin 22, IC2 or pin 11, IC8 which
changes between HIGH and LOW.
Replace the C293MAIN board.
The CPU is defective.
Verify the oscillator signal at pin 38 or 39 of the CPU
(IC7).
Replace the C293MAIN board.
The carriage operates abnormally.
The carriage does not operate
at all.
IC9 is defective.
Verify the CR motor phase control signals at pin 5, 6,
16,17, and motor drive signals at pin 1, 8, 11, 18 of
IC9
Replace the C293MAIN board.
The paper feeds abnormally. The paper is not fed at all. IC 10 is defective.
Verify the PF motor phase control signals at pin 16,
27 and motor drive signals at pin 6, 7, 8, 9 of IC10.
Replace the C293MAIN board.
Self test printing is abnormal.
The self test printing is not
executed or a particular dot is
not printed.
Any one transistor of Q2 -
Q26 is defective.
Verify the printhead drive signal at the corrector and
base of Q2 - Q26.
Replace the C293MAIN board.
Data from the host computer is
printed incorrectly.
Data corruption occurs when
the interface is used.
IC4 or CPU (IC7) is
defective.
-- Replace the C293MAIN board.