Panasonic KX-F680BX - Power Supply Section; Power Supply Block Diagram

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KX-F680BX/KX-F2681BX
3-10. POWER SUPPLY SECTION
(1) Key components for troubleshooting
The following components have been known to break frequently :
F101, D101, Q101, IC101, D201
This comes from our experience of experimental test. For example : power supply,
lighting surge voltage test, withstanding voltage test, intentional short circuit test.....etc.
Caution:
If you find a melted fuse in the unit, don't turn the power on without repairing the unit first. (Except the fuse.)
If you do the fuse will melt again. It has not been repaired. The cause exists same where else.
Because of circuit compostion :
If 24V is not output, don't output.
In most cases (our experience) the symptom is that nothing is output.
There is a high possibility in the primary side more than the secondary side.
5V ± 5%
24.5V ± 4%
25Ω
2W
1200Ω
1W
5V ± 5%
24.5V ± 4%
AC INPUT
Input
circuit
Rectifier
circuit
Converting
circuit
Q101
24V
output
circuit
DC-DC
converter
circuit
Voltage feed
back circuit
+5V
OUTPUT
+24V
GND
T101
primary
POWER SUPPLY BLOCK DIAGRAM
DUMMY LOAD to check voltage
secondary
Control
circuit
(IC101)
Over
current
circuit
1
2
3
4
5
6
7
8
V
V
GND
24V
5V
CN302
6
5
4
3
2
1
V
V
V
GND
5V
24V
CN301
:Voltage Meter