25
No. Symptom
Troubleshooting
procedures
Source of
problem
No.
Result
Component
HDD cableYES
Main PCBNO IC19
8-2
8-3
8
Format data
destroyed
Does executing FDISK
correct the problem?
YES
Go to No. 8-2NO
8-1
An operating system could
not be found
HDD
Replace the HDD.
Does operation return to
normal?
Replace the HDD cable.
Does operation return to
normal?
YES
Go to No. 8-3NO
1.7 SERIAL COMMUNICATION DIAGNOSIS
Make sure that connecting cables, connectors and AC adapter are not loose or disconnected prior to testing.
1-2
Is the same transmission
protocol set for both the
sending and receiving units?
YES
YES
NO
NO
No. Symptom
Troubleshooting
procedures
Source of
problem
Component
No.
Result
1
Data cannot be sent or
received.
Unit will not communicate
with another computer
when connected directly.
Does the RS-232C on the
Main PCB operate normally
under a loopback test?
1-3
Is the connection cable a
dedicated cross-patched
cable?
2-1
Is the same transmission
protocol set for both the
sending and receiving units?
2-2
1-1
Is the COM port properly
set?
YES Go to No. 1-2
NO Improper setting
2
Unit will not communicate
with modem.
3
Diagnostic Test reports
problem in serial port.
4
Go to No. 1-3
Check the
interface with the
other computer
Main PCB
IC37
IC25
Improper setting
YES
NO
Go to No. 2-2
Connection cable
YES
NO
Go to No. 2-3
Improper setting
Is the COM port properly
set?
3-1
YES
NO
Go to No. 3-2
Improper setting
YES
NO
Does the RS-232C on the
Main PCB operate normally
under a reverse test?
2-3
Check the
interface with the
other computer
Main PCB
IC37
IC25
Is the trasmission protocol
correct?
3-2
YES
NO
Go to No. 3-3
Improper setting
Does the modem operate
normally under a local
analog loopback test?
3-3
YES
NO
Line
Go to No. 3-4
Does the RS-232C on the
main board operate normally
under a loopback test?
Is the loop back device
properly attached to the
connector (for an external
loop back)?
3-4
4-1
YES
YES
NO
Modem
Main PCB
Main PCB
IC37
IC25
IC37
IC25
NO Improper setting
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