Panasonic KX-FT502RU-B / KX-FT502RU-W / KX-FT504RU-B / KX-FT504RU-W Service Manual ▷ View online
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12.5.7. Analog Board Section
This chapter provides the testing procedures required for the analog parts. A signal route to be tested is determined depending
upon purposes. For example, the handset TX route begins at the handset microphone and the signal is output to the telephone
line. The signal mainly flowing on this route is analog. You can trace the signal with an oscilloscope. The signal flow on each
route is shown in the Check Sheet here. If you find a specific problem in the unit, for example if you cannot communicate with
the MONITOR, trace that signal route locally with the following Check Sheet and locate the faulty point.
upon purposes. For example, the handset TX route begins at the handset microphone and the signal is output to the telephone
line. The signal mainly flowing on this route is analog. You can trace the signal with an oscilloscope. The signal flow on each
route is shown in the Check Sheet here. If you find a specific problem in the unit, for example if you cannot communicate with
the MONITOR, trace that signal route locally with the following Check Sheet and locate the faulty point.
12.5.7.1. Check Sheet for Signal Route
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12.5.7.2. Defective ITS (Integrated Telephone System) Section
1. No handset and monitor transmission / reception
Following the ITS section or NCU section, search for the route between the microphone and the telephone line (sending) or
between the telephone line and the speaker (receiving) where the signal disappears.
Check the components at that point.
between the telephone line and the speaker (receiving) where the signal disappears.
Check the components at that point.
2. No pulse dialing
3. No ring tone (or No bell)
4. No tone dialing
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12.5.8. Power Supply Board Section
12.5.8.1. 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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12.5.8.2. Troubleshooting Flow Chart
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