Hisense lcd40v57ca buzzing

[kodiac]

I would appreciate if someone could help me with a Hisense lcd40v57ca which has a buzzing sound from the back, that sounds like high voltage arching/escaping?
A 390uF 250wv cap on the power supply board is swollen up on top.
Also the tv will cycle on/off after it has been on awhile.

Does anyone know where I can obtain a 390uF 250wv cap in Canada?

Thank You

[kodiac]

Re: Hisense lcd40v57ca buzzing

Help Please?

[Pentium4]

Re: Hisense lcd40v57ca buzzing

You can find a cap in that size at Digi-Key. What was the original brand of the capacitor, and what are the dimensions of it? If the power board used cheap caps throughout it, while you're at it you might want to replace the rest of those too. Pictures are welcome

[tom66]

Re: Hisense lcd40v57ca buzzing

Often the plastic dome of a capacitor can bulge without the capacitor being failed, if it has a plastic cover. If you can push the dome down flat, the capacitor is likely OK.

[kodiac]

Re: Hisense lcd40v57ca buzzing

Thank You.
Sorry for the picture quality.
LCD40V57CA
I have to open the TV again for the caps names.

[kodiac]

Re: Hisense lcd40v57ca buzzing

The largest cap 390uF 250wv 105deg ( 3 cm x 3 cm ) which is bulged, is a brown SamYoung cap.
Others have TLC and S symbols.
The 390uF cap seems to be buzzing when the TV is On and emitting a whistle when the TV is Off/Standby.
When the TV is turned ON the buzzing begins and after approximately 15 min. the screen begins blinking periodically.
Does anyone have a list of good cap manufacturers.

Thank You.

[martino]

Re: Hisense lcd40v57ca buzzing

Does anyone know where I can obtain a 390uF 250wv cap in Canada?

Thank You

Where in Canada are you?

[kodiac]

Re: Hisense lcd40v57ca buzzing

Bump

[Pentium4]

Re: Hisense lcd40v57ca buzzing

This will work:
http://www.digikey.com/product-searc...=0&pageSize=25

[kodiac]

Re: Hisense lcd40v57ca buzzing

Thank You Sir.

[kodiac]

Re: Hisense lcd40v57ca buzzing

Is it true that increasing the voltage of a capacitor ( ex: 250wv to 350wv ) will shorten the life of the board.

[tom66]

Re: Hisense lcd40v57ca buzzing

If anything the complete opposite. The capacitor voltage ratng is a maximum, not what it operates at.

[kodiac]

Re: Hisense lcd40v57ca buzzing

Thank You

[tom66]

Re: Hisense lcd40v57ca buzzing

The main issue may be dimensions - check capacitor will fit before ordering. Compare dimensions on the Digikey page to the physical dimensions of the failed capacitor.

[kodiac]

Re: Hisense lcd40v57ca buzzing

Thank You

[kodiac]

Re: Hisense lcd40v57ca buzzing

Does anyone have a list of good cap manufacturers.

[tom66]

Re: Hisense lcd40v57ca buzzing

Panasonic, Rubycon, United/Nippon Chemi Con, Nichicon, Sanyo/Suncon, Fujitsu.

[kodiac]

Re: Hisense lcd40v57ca buzzing

Thank You

[kodiac]

Re: Hisense lcd40v57ca buzzing

Replaced 390uF 250wv cap ( with 300wv Panasonic from Digi-Key) in the power supply.
Problem solved, no more buzzing.

[kodiac]

Re: Hisense lcd40v57ca buzzing

Anyone familiar with a pair of faint light horizontal lines moving up the LCD screen which are most visible on dark background or night time programs?
I think these lines were called sound bars on older CRT televisions.