Sharp LC-40LE812E fuses blown

[gozotto]

Hello,
I repaired a Sharp LC-40LE812E TV with the main power board DPS-126CP B.
All fuses blown and the capacitor C7813 (220pF 1KV) was cracked. After replacing both, the TV works again without any problems. After 2 weeks the same problem apears with the same symptoms. What can the C7813 blown again and again? The schematic can be found here.

Thanks in Advance
gozotto

[Diah]

Re: Sharp LC-40LE812E fuses blown

with out looking to the manual-- if yours repair was on the primary section at PCB. then need complete circuit parts to replace at once..( Netzteil Set )

[gozotto]

Re: Sharp LC-40LE812E fuses blown

Did you mean the rectifier and the filter caps? I checked both and the filter caps have a low ESR.

[Diah]

Re: Sharp LC-40LE812E fuses blown

not rectifier .. upload clear photo to see C7813 in circuit

[dskall]

Re: Sharp LC-40LE812E fuses blown

I would replace it with a 2k and check all components in pfc circuit. Also check voltage at cap.

[gozotto]

Re: Sharp LC-40LE812E fuses blown

I replaced the C7813 with a 3kV one and now I hear some noise from board (transformer). Imeasured the voltage on the caps C7800A/B => 328V. I desolderd the MOSFET and checked it outside with the component tester. All good.
The C7813 can only blown with a voltage to high? But why?

[dskall]

Re: Sharp LC-40LE812E fuses blown

328v in standby? What is it when powered on?