KF-42WE620, KF-50WE620 - Sony TV Service Manual (repair manual). Page 8

Clearing the Result Display
To clear the result display to “0”, press the buttons on the Remote Commander sequentially when the diagnostic screen is displayed, as shown below:

1.  Power off (Set to Standby model)

2.  Display  

  Channel  5      

 Sound Volume  -  

 Power ON

3. Channel 8  

  ENTER

4.  Wait until the initial setup display appears.

5.  Disconnect the AC plug and then reconnect it.

Quitting the Self-Diagnostic Screen
To quit the entire self-diagnostic screen, turn off the power switch on the Remote Commander or the main unit.

Self-Diagnosis Function Operation
-  3 

:  Lamp cover  

If the lamp cover SW is opened then pin 1 of CN8034 on the A board is high. The LCD Engine u-com (pin 27 of 
IC3208 on the C2 board) detects it and turns the lamp off.

-   4 

:   Fan  

If Fan1, Fan2, Fan3, or Fan4 stops then pin 2, 5, 8 or 11 of CN8035 on the A board is high. The LCD Engine 
u-com (pin 24 of IC3208 on the C2 board) detects it and turns the lamp off.

-  4 

:  Temp  

If a temperature sensor on the H4 board detects a high temperature, 
or the IIC-E line connector (CN8041:A board,CN3951 H4 board) is not attached securely, the LCD Engine u-
com IIC-E Line detects it and turns the lamp off.

-  5 

:  Lamp drive  

If a lamp is not turned on, then pin 29 of LCD Engine u-com (IC3208 on the C2 board) is high and checks pin 
28 of LCD Engine u-com. If pin 28 is low, it is judged no high voltage.

-  6 

:  +BOVP  

If +17V line drops then pin 53 of MAIN u-com (IC3405 on the C2 board) is low and automatically turns off the 
main power.

-  7 

:  Audio  

If DC appears by the audio amp failure at the speaker line then it is detected by MAIN u-com (pin 59 of IC3405 
on the C2 board) and automatically turns off the main power.

-  8 

:  D-OVP  

If +3.3V, +2.5V, or +1.8V line over, then pin 49 of MAIN u-com (IC3405 on the C2 board) is low and 
automatically turns off the main power.

-  LAMP  :  Lamp  

If a lamp is not turned on, then pin 29 of LCD Engine u-com (IC3208 on the C2 board) is high and checks pin 
28 of LCD Engine u-com. If pin 28 is high the lamp is burned out.

IC41

27

IIC-E

LAMP COV

28

29

24

LAMP DRV

LAMP PROT

FAN PROT

4:Temp

IC3208

LCD Engine u-com

IC3405

MAIN u-com

49

59

53

SP-DC-PROT

LOW-B-ERR

D-OVP

H3/A board

8:D-OVP

6:+B OVP

G3/A board

G1/A board

17V-DET

CN8014

3:Lamp

cover

5:Lamp

driver

Lamp

4:Fan

Lamp

HV-DET

SW

S3999

T/A board

LAMP-PRT

Fan1

Fan2

Fan3

CN8003

FAN1-PRT

FAN2-PRT

FAN3-PRT

CN8022

Audio

amp

Audio

amp

7:Audio

IC4704

IC8504

C2 board

AU board

A board

Lamp driver

Temp

sensor

+3.3V
+2.5V
+1.8V

+17V

1

2

3

1

2

8

5