Panasonic SA-BTT775GA, Service Manual

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47
8 Troubleshooting Guide
8.1. Troubleshooting Guide for F61 and/or F76
y p ( )
g
( )
Set cannot Power ON:
Condition 1: With
Stanby LED on
1
2
3
1
2
3
Photocoupler PC5702,
PC5799 1
2
PC5702/PC5799 solder crack,
dry joint ,short circuit,open
circuit,etc
Solder crack,dry joint ,short
circuit,open circuit,etc
Switching IC IC5701
AC cord
AC Inlet P5701
1 Faulty AC cord, loose
connection
2
2
Solder crack,dry joint ,short
circuit,open circuit,etc 4
Check FFC connection/
alignment from SMPS (JW2)
to Main (CN2004) 2
P5701 solder crack, dry joint
etc
Faulty IC5701, pin 1 and 2
shorted, VCC short to GND, etc
Faulty IC5799, pin 5 and 7
shorted, VCC short to GND, etc
Switching IC IC5799
Set can Power ON
then F61
Set can Power ON
then F76
Set can Power ON
working normally for
sometime then F61
Condition 2: With
Stanby LED Off or
flickering
3
1
2
3
3 F1 Fuse open Fuse F1
DC-DC circuit
1 Thermal Diode D5802
SMPS FFC loose
LDO regulator
4 Photocoupler PC5720
1 Transformer T5701
2 Photocoupler PC5720
1a Pin 11/12 shorted to pin 13/14
1b
1a
1b
Pin 16 shorted to pin 17
L2902 Open (no input to
IC2901)
Faulty IC2901 (no output
voltage at pin 10 and 11)
1a
1b
Improper contact between
D5802 to heatsink
OTP (thermal) protection
trigger prematurely
3a Faulty QR7071 Transistor diode
check (cannot switch ON then
NO +9V)
3b LB2843 Open (+12V line going
to Panel PCB CN2002)
1c Faulty Q2902 and Q2903
(regulator)
1d L2908 open (No DC +5V)
1e R7003 open (No DC +9V)
1) Refer to Fig. 1. SMPS P.C.B.
Refer to Fig. 1. SMPS P.C.B.
Refer to Fig. 1. SMPS P.C.B.
Refer to Fig. 1. SMPS P.C.B.
Refer to Schematic Diagram of
SMPS Circuit (Item 17.7) for
terminal pin count on primary and
secondary terminals
SMPS Circuit (Item 17.7)
2) Refer to Schematic Diagram of
1) Refer to Fig. 2. Digital P.C.B.
Digital (Power) Circuit (Item 17.2)
2) Refer to Schematic diagram of
1) Refer to Fig. 2. Digital P.C.B.
Digital (Power) Circuit (Item 17.2)
2) Refer to Schematic diagram of