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37

This section illustrates the checking procedures when upon detecting the error of “F61” and/or “F76” after power up of the unit. It is
for purpose of troubleshooting and checking in SMPS P.C.B.. 

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 Q2904 Transistor diode

check (cannot switch ON then
NO +9V)

3b LB2774 Open (+9V line going

to Panel PCB CN2002)

1c Faulty Q2902 and Q2903 

(regulator)

1d L2908 open (No DC +5V)

1e R2399 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. Main P.C.B.

Main Circuit (Item 17.3)

2) Refer to Schematic diagram of

1) Refer to Fig. 2. Main P.C.B.

Main Circuit (Item 17.3)

2) Refer to Schematic diagram of

38

Fig. 1. SMPS P.C.B.

39

Fig. 2. Main P.C.B.

40

DVD Laser Diode Current Measurement

CD Laser Diode Current Measurement

1. Measurement the voltage (V

CD

) on the testpoints CL8530(+) & CL8531(-).

This is voltage across R8566 which has a resistance value of 4.7 ohm.

2. Calculate the CD Laser current by the following formula:

1. Measurement the voltage (V

DVD

) on the testpoints CL8530(+) & CL8532(-).

This is voltage across R8556 which has a resistance value of 4.7 ohm.

2. Calculate the DVD Laser current by the following formula:

Refer to 8.2.1. 
Backend P.C.B. 
(Fig. 3. Backend 
P.C.B.)

Refer to 8.2.1. 
Backend P.C.B. 
(Fig. 3. Backend 
P.C.B.)

3. Specification for CD laser current is

58 mA

3. Specification for DVD laser current is

58 mA