Read Panasonic KX-TG2560B / KX-TG2560S Service Manual online
39
KX-TG2560B/KX-TG2560S
4. Power Supply Circuit
Function:
Power from the AC adaptor passes through a regulating block consisting of IC301.
Circuit Operation:
IC301 is a regulated power supply. The voltage at point A is regulated to 6 V by IC301.
The voltage at point B is dropped by D901, D304~D305, D701 and D710 to 4.6 V.
The voltage at point C is dropped by D303, D900 to 4.1 V.
3. Auto Disconnect Circuit
Function:
This circuit is used to detect the fact that another telephone connected to the same line is OFF-HOOK while the unit is in a
receiving status or OGM transmitting status.
Circuit Operation:
The telephoneline voltage is mositured by pin40 of IC701, the presence/absence of a parallel connection is
determined when the voltage changes by 0.2V or more.
When the set detects the parallel-connected telephone is OFF HOOK status, the line is disconnected.
Circuit Diagram
Circuit Diagram
1
2
L101
C103
~
~
D101
C104
R102
R108
RLY
DCIN
USE-CTL
Q103
Q101
Q102
R124
R105
R104
R101
C112
L102
CN101
SA101
99
40
15
P101
R109
R103
IC701
DSP
D901
Q902
IC301
DC-JACK
12, 75, 93 pin
34 pin
B
52 pin
B
C
51 pin
B
37 pin
B
Pow B
22
Pow B
24
A
D710
D304
D303 D900
D701
D305
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