Epson 2070 Service Manual - Page 135

Repairing The C186 Main Board Assembly

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LQ-2070 Service Manual Troubleshooting 5.5 REPAIRING THE C186 MAIN BOARD ASSEMBLY This section provides instructions to repair the C186 MAIN board assembly. It describes various problems, symptoms, likely causes, and solutions. The checkpoint column provides proper waveforms, resistance values, and other information for each component of C186 MAIN. Note: This information is necessary only for servicers who repair to the component level. Servicers who repair to the unit level (including all servicers in the U.S.) can ignore this section. Problem Table 5-7. Repairing the C186 MAIN Board Assembly Cause Checkpoint Solution Check the voltage waveforms of the VCC signal (CH1: IC10 pin 3 ) and VOUT signal (CH2: IC10 pin 1) when power is turned on. Replace IC10. The printer does not operate at all. Reset IC10 is defective. The PROM (IC3) is not Check for a change in the signal from selected. HIGH/LOW at pin 137 of IC2. Replace IC2 (or replace the main board). ^ The PSRAM (IC5) is Check for a change in the signal from Replace IC2 (or ^ not selected HIGH/LOW at pin 132 of the IC. replace the main board). Rev.A 5-13

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5.5 REPAIRING THE C186 MAIN BOARD ASSEMBLY
This section provides instructions to repair the C186 MAIN board assembly.
It describes various problems,
symptoms, likely causes, and solutions. The checkpoint column provides proper waveforms, resistance
values, and other information for each component of C186 MAIN.
Note:
This information is necessary only for servicers who repair to the component level.
Servicers who
repair to the unit level (including all servicers in the U.S.)
can ignore this section.
Table 5-7. Repairing the C186 MAIN Board Assembly
Problem
Cause
Checkpoint
Solution
The printer
does not
operate at all.
Reset IC10 is defective.
Check the voltage waveforms of the VCC
signal (CH1: IC10 pin 3 ) and VOUT signal
(CH2: IC10 pin 1) when power is turned
on.
Replace IC10.
^
The PROM (IC3) is not
selected.
Check for a change in the signal from
HIGH/LOW at pin 137 of IC2.
Replace IC2 (or
replace the main
board).
^
The PSRAM (IC5) is
not selected
Check for a change in the signal from
HIGH/LOW at pin 132 of the IC.
Replace IC2 (or
replace the main
board).
LQ-2070 Service Manual
Troubleshooting
Rev.A
5-13