Communication Failure; Problem, Cause And; Corrective Action; Power Led Not Lighting - Canon CanoScan 9900F Service Manual

CHAPTER 5
III. PROBLEM, CAUSE AND CORRECTIVE ACTION
Defects of CanoScan 9900F may fall into one of five categories listed below:

* Power LED not lighting

* Communication failure

* Scanning unit movement failure
* Poor image quality
* Acoustic noise
A. Power LED Not Lighting
Possible Cause
AC adapter is unplugged
from the outlet
AC Adapter cable is
disconnected from the scanner
AC adapter output voltage
failure
Button PCB failure
Main PCB failure
Main PCB connection failure
B. Communication Failure
Possible Cause
USB cable connection failure
Scanner communication failure
Scanning unit failure
5 - 4
Related Parts
None
None
AC Adapter
Button PCB
Main PCB
None
Table 5-1
Related Parts
Visual check
USB cable
Trial replacement
Main PCB
Scanning unit Trial replacement
Table 5-2
COPYRIGHT 2003 CANON INC. CANOSCAN 9900F REV.0 FEB. 2003 PRINTED IN JAPAN (IMPRIME AU JAPON)
Check Method

Corrective Action

Plug the AC adapter into
Visual check
the outlet
Connect the AC adapter cable
Visual check
to the power connector on the
scanner
Replace the AC adapter
Output voltage
(+24V) check
Replace the button PCB
Tester check
Replace the main PCB
Tester check
(+24V, GND)
Properly connect the main PCB
Visual check

Corrective Action

Check Method
Connect the USB cable
properly
Replace the main PCB
Replace the scanning unit