Table 1-34 Error Code U3-4 Laser Failure Power Off/On - Xerox DOCUPRINT N4525 Service Quick Reference Manual

RAP 1-6
Error Code U3-4
There is a problem with the Start of Scan (SOS) Sensor.
Logic Control on the Print Engine Controller Board detected that the time between signals
from the Start of Scan Sensor was shorter than specified.

Table 1-34 Error Code U3-4 Laser Failure Power Off/On

Step Actions and Questions
1 RESET
1. Switch off printer main power.
2. Wait one minute.
3. Switch on printer main power.
Does the U3-4 error code appear?
2 LOW VOLTAGE POWER SUPPLY +5VDC
CHECK
Measure the voltage between J400, pins 1, 2 & 3 (on the
Print Engine Controller Board) and frame ground.
Is there +5VDC between J400, pins 1,2 & 3 and
frame ground?
3 PRINT ENGINE CONTROLLER BOARD
REPLACEMENT
Replace the Print Engine Controller Board (RRP 1-72).
Does the error code appear?
4 LASER SCANNER REPLACEMENT
Replace the Laser Scanner Assembly (RRP 1-47).
Does the error code appear?
5 The following printer components and areas are
associated with this specific problem. One or more of
these components or areas may have failed partially or
completely. If you cannot isolate this problem using the
steps in this Repair Analysis Procedure, replace each
component or troubleshoot each area listed below, one at
a time, until you isolate and solve the problem.
Wiring and connectors linking the components


Input/Output Board (RRP 1-70).


1-52 DocuPrint N4525 Network Laser Printer - Service Guide
Laser Failure
Power Off/On
Yes
Go to step 2
Go to step 3
Go to step 4
Go to step 5
No
Suspect an
intermittent
problem with
the Print
Engine
Controller
Board, the
Laser Diode
board, the
SOS Sensor,
or the
connectors
and wiring
linking these
components.
Replace the
Low Voltage
Power Supply
Assembly
(RRP 1-67)
Problem
solved
Problem
solved