Sharp LC-37x20e power on but only for few seconds

[budm]

Re: Sharp LC-37x20e power on but only for few seconds

Can we see good closed up pictures of the top and the bottom side of the board around the area where you replaced the IC7601?

[clamel]

Re: Sharp LC-37x20e power on but only for few seconds

Hello,
IC7601 was copy and paste error.. I had to replace IC7904.. summarizing:

IC7904 (9NK2510293234) TNY264PN --> It was very HOT. Replaced because it burnt after freezing. But during freezing it, the TV power came to life for some seconds, before this component burnt definitively.

R7920 replaced because damaged after IC7904 burnt

R7918 replaced but it was good

IC7906 PC123Y82FZ0F --> Replaced, but after desoldering repeating tests on the old it had no problem.



In attach some photo centered on IC7904, but also other replacements are visible.

thank you very much for your patience

[budm]

Re: Sharp LC-37x20e power on but only for few seconds

Is the snubber diode D7906 tested OK?

[clamel]

Re: Sharp LC-37x20e power on but only for few seconds

Is the snubber diode D7906 tested OK?

yes, It seems to working fine.. with multimeter in diode mode, I read 0.479 V in one way, and OL in the other way. The readings are done with component soldered on the board.

[clamel]

Re: Sharp LC-37x20e power on but only for few seconds

Hello,
I made some voltage measurement with power board connectet to AC.

IC7904 - TNY264PN (using PIN2 as GND)
pin1 - BP 5.85V
pin2 - S 0V
pin3 - S 0V
pin4 - EN/UV 12.8 mV
pin5 - D 309V
pin7 - S (HV) 0V
pin8 - S (HV) 0V

I also measured voltage at some near components

D7906 13V
D7905 7.4V
C7907 5.85V
D7910 4.22V

Is IC7904 working properly looking these voltages? What can I check in next steps?

thanks

BR

[clamel]

Re: Sharp LC-37x20e power on but only for few seconds

Maybe ic7904 I replaced is bad? I don't undestand why I get only 1v instead of 5v