Read Panasonic CF-28 Service Manual online
4.4.7 SERIAL COMMUNICATION DIAGNOSIS
Make sure that connecting cables, connectors and AC adapter are not loose or disconnected prior to
testing.
testing.
No.
Symptom
Troubleshooting
procedures
Source of
problem
No.
Result
Component
HDD cable
YES
Main PCB
NO IC43
8-2
8-3
8
Format data
destroyed
destroyed
Does executing FDISK
correct the problem?
correct the problem?
YES
Go to No. 8-2
NO
8-1
An operating system could
not be found
not be found
HDD
Replace the HDD.
Does operation return to
normal?
Replace the HDD cable.
Does operation return to
normal?
Does operation return to
normal?
Replace the HDD cable.
Does operation return to
normal?
YES
Go to No. 8-3
NO
1-2
Is the same transmission
protocol set for both the
sending and receiving units?
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.
received.
Unit will not communicate
with another computer
when connected directly.
with another computer
when connected directly.
Does the RS-232C on the
Main PCB operate normally
under a loopback test?
Main PCB operate normally
under a loopback test?
1-3
Is the connection cable a
dedicated cross-patched
cable?
dedicated cross-patched
cable?
2-1
Is the same transmission
protocol set for both the
sending and receiving units?
protocol set for both the
sending and receiving units?
2-2
1-1
Is the COM port properly
set?
set?
YES
Go to No. 1-2
NO
Improper setting
2
Unit will not communicate
with modem.
with modem.
3
Diagnostic Test reports
problem in serial port.
problem in serial port.
4
Go to No. 1-3
Check the
interface with the
other computer
interface with the
other computer
Main PCB
IC47
IC48
IC48
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?
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?
Main PCB operate normally
under a reverse test?
2-3
Check the
interface with the
other computer
interface with the
other computer
Main PCB
IC47
IC48
IC48
Is the trasmission protocol
correct?
correct?
3-2
YES
NO
Go to No. 3-3
Improper setting
Does the modem operate
normally under a local
analog loopback test?
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?
main board operate normally
under a loopback test?
Is the loop back device
properly attached to the
connector (for an external
loop back)?
properly attached to the
connector (for an external
loop back)?
3-4
4-1
YES
YES
NO
Modem
Main PCB
Main PCB
NO
Improper setting
IC47
IC48
IC47
IC48
IC48
IC47
IC48
4 - 11
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