2-12 Service Manual
4025-XXX
Error Code 903
There is a problem reading information from RAM.
Logic Control on the MCU PWB had a problem reading information from RAM.
2 +24VDC CHECK
Measure the voltage between P/J207-1 and FG.
Is there +24VDC between P/J207-1 and FG?
Replace the
“Engine
Board (MCU
PWB)” on
page 4-92
Go to step 3
3 +24VDC CHECK
Measure the voltage between J400-8 and FG on the MCU
PWB.
Is there +24VDC between J400-8 and FG?
Go to step 4 Use the Block
Diagrams in
the printer
service
manual to
troubleshoot a
loss of
+24VDC
4 PRINTHEAD REPLACEMENT
Replace the “Printhead Assembly” on page 4-57
Does the error code appear?
Go to step 5 Problem
solved
5 The following printer FRUs and areas are associated with this
specific problem. One or more of these FRUs or areas may
have failed partially or completely. If you cannot isolate this
problem using the steps in this Service Check, replace each
FRU or troubleshoot each area listed below, one at a time, until
you isolate and solve the problem.
• Wiring and connectors linking the FRUs
• Interlock switches and circuits
• I/O PWB - Go to “I/O PWB” on page 4-89.
Step Actions and Questions Yes No
1 RESET
1. Switch off printer main power.
2. Wait one minute.
3. Switch on printer main power.
Does the 903 error code appear?
Go to step 2 Suspect an
intermittent
problem with
the MCU
PWB, the
LVPS, or the
connectors
and wiring
linking these
FRUs.
Step Actions and Questions Yes No