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LC-42XD10E/RU

4 – 21

FRC circuit failure         

Note: The SD signal (576i  480i) alone passes through the FRC circuit. (The HD signal does not go through.)

Does the image appear with the HD 
signal, but not with the SD signal ?  

Does anything unusual (which or 
blackish screen, block noise, for 
example) appear on the screen?      

Does the image look unusual with 
the power switch turned on?    

YES

YES

YES

Is the power supplied to IC3301 
(FRC)?  
Is there the FRC-IN signal input at pins 
(142) and (13) of IC3301? 
Check the soldering condition. 

Is there the specified RESET-A signal 
input at pin (39) of IC3301(FRC)? 
(60 ms delay design)     

Check the connection between pin 
(R22) of IC3002 (V-PRO.) and pin 
(142) of  IC3301 (FRC) as well as 
that between pin (N20) of IC3302 
and pin(13) of IC3301.    

YES

NO

Replace IC3301(FRC).  

Check "RESET-A " signal pin(34) of 
IC1710 (FPGA).     

 

LC-42XD10E/RU

4 – 22

      

Backlight failure to light up

Do all the fluorescent tubes light up?

NO

Check the individual fluorescent 
tubes for light-up failure.

YES

Replace any defective fluorescent 
tubes with new ones.

YES

Is the power supplied to CN7501 on 
the inverter unit?   

NO

Check the connection between power 
unit and inverter unit.      

YES

Is the fuse (F7501 or F7502) in the 
inverter unit circuit functioning?

NO

Replace the blown-out  fuse (F7501 
or F7502) on the inverter unit. Turn on 
the power again. 
If the fuse gets blown out again, 
check the short-circuited spot.     

YES

Check the transformer (T7501-
T7511, T7601-T7606) and their 
peripheral circuits as well as IC7501 
and their peripheral circuits.
    

YES

Is the VCC power supplied to the 
control IC (IC7501) on the inverter 
unit? 

NO

Check the circuit connected with the 
VCC terminal on the inverter control 
IC (IC7501).     

YES

Has each control signal come to 
CN7502(LB)? 
(STB,OSC,OFL)  

NO

Have the STB,OSC and OFL signal 
come to P1701(LB) in the MAIN sub-
strate?  

NO

 Check pins (89),(19) and (17) of 
IC1710 (main PWB) .

YES

Is the specified control signal input-
ted at IC7501 (INV-CTL) on the 
inverter unit. 

NO

Check the line between CN7502 and 
IC7501.
   

 

YES

Are the Q7501 and Q7502 transis-
ters at the primary side of T7501 
functioning? 

NO

Check the power line of IC7501, its 
peripheral circuits or replace IC7501.    

 

YES

Is the secondary circuit of T7501 
functioning. 

NO

Replace T7501 or the T*** trans-
former for the fluorescent tubes, or 
check their peripheral circuits.  

 

LC-42XD10E/RU

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 LCD failure 1

Does a single or several verti-
cal stripes appear on the LCD 
screen? 

Does a single or several hori-
zontal stripes appear on the 
LCD screen?

Do luminescent or black dots 
appear on the screen?

 Is the on-screen image rip-
pling or distorted?

Replace the LCD panel.

 LCD failure 2

The backlight func-
tions.  Does not the 
image come out in the 
LCD screen 
(screen black) ? 

Does the entire LCD 
screen look whitish all 
over?

Does the QS drive func-
tion?

 Are the data bit drop-
out?
(No solution even when 
turning on and off the QS 
drive)

Is the gamma correc-
tion as specified?

Replace the LCD control unit.

LC-42XD10E/RU

4 – 23

 LCD failure 1

Does a single or several verti-
cal stripes appear on the LCD 
screen? 

Does a single or several hori-
zontal stripes appear on the 
LCD screen?

Do luminescent or black dots 
appear on the screen?

 Is the on-screen image rip-
pling or distorted?

Replace the LCD panel.

 LCD failure 2

The backlight func-
tions.  Does not the 
image come out in the 
LCD screen 
(screen black) ? 

Does the entire LCD 
screen look whitish all 
over?

Does the QS drive func-
tion?

 Are the data bit drop-
out?
(No solution even when 
turning on and off the QS 
drive)

Is the gamma correc-
tion as specified?

Replace the LCD control unit.