LC-52XD1E (serv.man5). Trouble Shooting Table - Sharp TV Service Manual (repair manual). Page 22

LC-46/52XD1E-RU

6 – 22

52INV         

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 
tube (s) with new one (s).

Is the power supplied to CN7507B 
and CN7507D on the inverter unit?   

NO

Check the connection between power 
unit and inverter unit.      

YES

Iis the F7501 A/B/C/D fuse in the 
inverter unit circuit functioning?

NO

Replace the blown-out F7501 A/B/C/
D fuse on the inverter unit. Turn on 
the power again. 
If the fuse gets blown out again, 
check the short-circuited spot.     

YES

Check T7501A, T7501B, T7501C 
and T7501D and their peripheral cir-
cuits as IC7502B and their periph-
eral circuits.    

YES

Is the VCC power supplied to the 
control IC (IC7502B) on the inverter 
unit?   

NO

Check the circuit connected with the 
VCC terminal on the inverter control 
IC (IC7502B).     

YES

Has each control signal come to 
CN7508B? 
(INV-OFL,INV-OSC,INV-STB,INV-
BRT)  

NO

Have INV-OFL/OSC and the INV-
STB signal come to P1701(LB) in the 
MAIN substrate?    

NO

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

YES

Is the specified control signal input-
ted at IC7502B (INV-CTL) on the 
inverter unit. 

NO

Check the line between CN7508B 
and IC7502B.     

 

YES

Are the Q7501A ,Q7502A, Q7503A 
and Q7504A transisters at the pri-
mary side of T7501A functioning? 

NO

Check the power line of IC7502B,its 
peripheral circuits or replace 
IC7502B.     

 

YES

Is the secondary circuit of T7501A 
functioning.  

NO

Replace T7501A or the T75*** trans-
former for the fluorescent tubes, or 
check their peripheral circuits.