Troubleshooting Guide; No Operation - Panasonic KX-DT543-B Service Manual

KX-DT543/KX-DT543-B/KX-DT546/KX-DT546-B

8 Troubleshooting Guide

8.1.

No Operation

[ Power supply circuit ]
Remove L221(VDD33), L220(VCCA33) and
L222(VCC33) from Main PCB.
Disconnect Operation PCB from Main PCB.
Connect DPT to PBX.
Confirm the voltage between Pin + and Pin - of
C550.
Does it switch into 15V or 40V periodically?
Confirm the voltage between TP:3.3V and
TP:UART_GND.
Does it switch into 0V or around 3.3V periodically?
Remove DPT from PBX.
Confirm the resistance value between "VDD33" and
TP:UART_GND.
Is it about 367 ?
Confirm the resistance value between "VCCA33"
and TP:UART_GND.
Is it higher than 1M ?
Confirm the resistance value between "VCC33" and
TP:UART_GND.
Is it higher than 1M ?
Confirm the resistance value between Pin1 and
Pin10 of CN160.
Is it higher than 1M ?
Put L221(VDD33), L220(VCCA33) and
L222(VCC33) back in place.
Connect Operation PCB.
Connect DPT to PBX.
Confirm the voltage between TP:3.3V and
TP:UART_GND.
Is it about 3.3V?
YES
YES
YES
YES
YES
YES
YES
GO TO A
Check the soldering.
Resolder or replace parts as needed.
NO
Related parts: JK300,L301,L302,T300,D300,
C550,C551
NO
Related parts: IC510,L309,D315,C550,C557,
C558,R541,R547,R548
Related parts: D301,C306,R306-310,Q301,
C310,C311,R342,R343,C330,
NO
Q331,D532,R348,R349,C333,
Q332,D533,R351-355,C335,
C336,IC300
Related parts:IC410,C420,C453,R557,R427,
NO
C421,C418,C419,C455
all parts around "MICBIAS"
Related parts:IC410,IC401,IC300,
NO
LCD module,
all capacitors connected VCC33
NO
Related parts:[Ope PCB]
D160,C160,C161,IC150,
C150-154,C156,C10,C12
Related parts: [Main CPB ] CN400
NO
[Ope PCB] CN160
20
IC172,C172,