Panasonic KX-G8300 Service Manual And Technical Manual page 63

KX-G8300
Troubleshooting Step 4:| STBY mode remains even when "TX" is pressed.
Possible Causes
© —— Control board failure
O __ Improper connection of connector CN6 on processor board
Checks and Repairs
1) | Check whether the CN6 connector on the processor board is loose.
2) Observe the signal of pin 5 of the same CN6 connector on an oscilloscope.
Check that a pulse train (approx. 100 Hz,-5Vp-p) is observed while the TX key is kept pressed.
If the pulse train does not appear, the problem may lie in the control board which should be
replaced.
Troubleshooting Step 5:| No echos or noise on the screen.
Possible Causes
1) Problem with video signal connections (open or short)
2) IF amplifier board failure
3) Processor board failure
Checks and Repairs
1) | Use a multimeter to check the connections (for continuity/shortcircuiting) of the video signal line in
the signal cable connecting the antenna and display units.
2) Use the oscilloscope to check the waveforms at pin 7 of connector CN2 on the processor board.
A signal such as that shown below should be observed.
OV
Fig. 64
If a signal simular to the above signal is not observed even when the TUNE, A.C. Sea and GAIN
controls of the display unit are adjusted, the problem may lie with the IF amplifier board which
should be replaced.
3) When the above signal appears normal and no echoes and noise appear on the screen, the
problem may lie with the processor board which should be replaced.
[Si]
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