Panasonic KX-FC228UA-T / KX-FC228RU-T Service Manual ▷ View online
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12.5.6.2. Defective fax NCU section
1. No Speakerphone and no monitor reception
Perform a signal test in the FAX NCU section and locate a defective point (where the signal disappears) on each route between
the microphone and the telephone line (sending), or between the telephone line and the speaker (receiving). Check the compo-
nents at that point. Check Sheet for Signal Route (P.124) is useful for this investigation.
the microphone and the telephone line (sending), or between the telephone line and the speaker (receiving). Check the compo-
nents at that point. Check Sheet for Signal Route (P.124) is useful for this investigation.
2. No pulse dialing
3. No ring tone (or No bell)
REFERENCE:
Check Sheet for Signal Route (P.124)
NCU Section (P.37)
NCU Section (P.37)
4. No tone dialing
REFERENCE:
Check Sheet for Signal Route (P.124)
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12.5.7. Power Supply Board Section
12.5.7.1. Key Components for Troubleshooting
Check the following parts first: F101, D101-D104, C106, Q101and IC101.
This comes from our experience with experimental tests. For example: power supply and lightning surge voltage test, withstanding
voltage test, intentional short circuit test, etc.
This comes from our experience with experimental tests. For example: power supply and lightning surge voltage test, withstanding
voltage test, intentional short circuit test, etc.
Caution:
If you find a melted fuse in the unit, do not turn on the power until you locate and repair the faulty parts (except for the fuse);
otherwise the fuse will melt again and you cannot pinpoint the faulty point.
otherwise the fuse will melt again and you cannot pinpoint the faulty point.
In most cases, the symptom is that nothing is output. It is more likely that the fault is in the primary side rather than the secondary
side. Check the primary side first.
side. Check the primary side first.
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12.5.7.2. Troubleshooting Flow Chart
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12.5.7.3. Broken Parts Repair Details
(D101, D102, D103, D104)
Check for a short-circuit in terminal 4. If D101, D102, D103 and D104 are short-circuits, F101 will melt (open).
In this case, replace all of the parts (D101, D102, D103, D104, F101).
Check for a short-circuit in terminal 4. If D101, D102, D103 and D104 are short-circuits, F101 will melt (open).
In this case, replace all of the parts (D101, D102, D103, D104, F101).
(Q101)
The worst case of Q101 is a short-circuit between the Drain and Gate because damage expands to the peripheral circuit of Q101.
This is due to a very high voltage through the Gate circuit which is composed of R110, R112, D107 and IC101.
You should change all of the parts listed as follows.
F101, Q101, R110, R112, D107, IC101
The worst case of Q101 is a short-circuit between the Drain and Gate because damage expands to the peripheral circuit of Q101.
This is due to a very high voltage through the Gate circuit which is composed of R110, R112, D107 and IC101.
You should change all of the parts listed as follows.
F101, Q101, R110, R112, D107, IC101
(D201)
If D201 is broken, the oscillation circuit in the power supply cannot operate. Check it with an electric tester.
If D201 is broken, the oscillation circuit in the power supply cannot operate. Check it with an electric tester.
