Panasonic KX-FT21BX Service Manual page 8

KX-FT21BX/KX-FT21BX-W
(2)Troubleshooting flow chart
YES
Replace the broken part and IC101.
NO
Is F101 open?
YES
Replace F101.
NO
Is D101-D104 short?
YES
Replace D101-D104.
NO
Are D-G, D-S, and
S-G (Q101) short?
YES
Replace Q101 and R105.
Power ON
YES
24V output OK?
NO
Power OFF
(Control circuit check)
Are R107, R109
and D106 OK?
NO
Power ON
YES
24V output OK?
NO
Power OFF
(Model KX-FT21BX/KX-FT21BX-W)
* When testing for a short
circuit, turn off first and then
turn on when you start to
check output voltage (24V or
5V) as illustrated in the flow
chart.
* An analog tester is
recommended to use for
checking a short circuit.
A
A
-8-
5V output OK?
NO
Power OFF
Replace D202.