Service manual

REPAIR
Troubleshooting
SERVICE MANUAL
3-12
Problem:
The FDD does not operate correctly
Points to Check Probable Cause Corrective Action Repair
Is FDD power harness correctly
connected?
FDD power harness is
not correctly
connected.
Reconnect. Replace the
FDD power
harness.
Is FDD ribbon cable correctly
connected?
FDD power cable is
not correctly
connected.
Reconnect. Replace the
FDD power
cable.
ERROR on performing the FDD self-
test (Since performing this destroys
all data on the disk, always use a
disk containing data whose loss is
not important.)
Defective FDD or FDD
ribbon cable.
Defective FDC (#5)
Replace the FDD or
the FDD ribbon cable,
as req.
Replace the Main
PCB.
Replace the
FDD or cable.
Replace #5.
Is oscillator XT2 operation correctly?
(Use an oscilloscope to check)
Defective XT2 Replace XT2.
Problem:
Communication function (optional fax/modem)do not work or do not work properly.
Points to Check Probable Cause Corrective Action Repair
Is the fax/modem cable connected
properly?
Faulty/improper
connection.
Reconnect cable. Replace cable.
Is each level of CN1 signal approx.
±10V?
Defective #1 Replace the Main
PCB.
Replace #1
Do the TXD of the CBIC (#8) signal
change?
Defective #8 Replace the main
PCB.
Replace #8.
Do the RXD of the CBIC (#8) signal
change?
Defective #1 or circuit
on the Main PCB
Replace the Main
PCB.
Replace #1.
Problem:
An error message appears on the display.
Points to Check Probable Cause Corrective Action Repair
(1) "Check printer Press any key to
continue." (After executing print
command) Is the paper path
clear
Possible paper jam. Check/clear paper
path
Is the CA index (home position)
switch working properly?
Home position cannot
be detected (defective
index switch)
See Problem 3,
"Home position Switch
Checks".
Is ROM/RAM (#11,#12/#10)
working properly?
Defective ROM/RAM
(#11,#12/#10)
Execute the Self-Print
test (in SELF TEST)
and verify that the
ROM/RAM (sum-
check) test is normal
(if error on Self-Test,
replace the Main
PCB).
Replace the
Main PCB
12
13
11