35x30mm 450V 150uF replacement

[rustytierod]

2 exploded on a LG LCD tv PS board. Right behind a heat shield.

Looking to anyone's expertise on this one. Trying to keep the dimensions the same since its in a little foot print. can't find single ones for sale without the 30 week lead time!

[mockingbird]

Re: 35x30mm 450V 150uF replacement

If you meant 35x30 (Width x Height), then here:
http://www.digikey.com/product-detai...C30-ND/2428153

Will cost you some.

[rustytierod]

Re: 35x30mm 450V 150uF replacement

I just found some on ebay that are 30x30. What could possibly be the difference?

[rustytierod]

Re: 35x30mm 450V 150uF replacement

I guess the digikey ones are rated at 105C?

[vinceroger69]

Re: 35x30mm 450V 150uF replacement

yes rated 105c

[rustytierod]

Re: 35x30mm 450V 150uF replacement

So given another cap with the exact same specs, but slightly different dimensions and in this case smaller volume, 30x30, is there some difference that would create a problem?

Is there some difference in the dielectric design to keep uF the same?

[mockingbird]

Re: 35x30mm 450V 150uF replacement

Don't buy capacitors off eBay. They're fakes and are also probably under-spec.

[Agent24]

Re: 35x30mm 450V 150uF replacement

So given another cap with the exact same specs, but slightly different dimensions and in this case smaller volume, 30x30, is there some difference that would create a problem?

Is there some difference in the dielectric design to keep uF the same?

Different manufacturer, different design possibly, different electrolyte formula etc.

If the new capacitors are smaller, you should probably check that the ripple current rating is not lower than the originals, if it is, you may get problems. Of course, newer capacitors can be designed better and fit the same thing in a smaller can, so the answer is.. It depends.

Check datasheets of both


But I would be worried about what caused them to explode in the first place... AFAIK only CapXon HP were known to self-destruct, for anything else, suspect a problem elsewhere in the circuit causing overvoltage.

If they are mains filter caps in PSU without PFC, likely you have a screwed bridge rectifier (or someone replace it backwards or something)

[rustytierod]

Re: 35x30mm 450V 150uF replacement

They were "SAMWHA" make. I don't know how to tell if there is power factor correction (that is what you mean)?

[mockingbird]

Re: 35x30mm 450V 150uF replacement

I have had a primary capacitor explode on me in an LCD TV because the bridge rectifier failed. You might want to check that out.

[budm]

Re: 35x30mm 450V 150uF replacement

At 450Vdc rating, then it will have PFC Voltage booster circuit.

[Agent24]

Re: 35x30mm 450V 150uF replacement

If it has PFC, perhaps the PFC controller went nuts and boosted the voltage far too high?

[budm]

Re: 35x30mm 450V 150uF replacement

That is one possibility, tom66 had that experience with out of regulation of the PFC Voltage booster circuit.

[rustytierod]

Re: 35x30mm 450V 150uF replacement

Some smaller 2200uf 10v caps nearby had buldged on top but not exploded. I should note only one of the filter caps actually exploded. The other just got really bloated/buldged.

The TV was becoming dimmer and dimmer to watch and would take longer and longer to get a picture on the screen and eventually wouldn't power on at all (at which point I assume large cap exploded).

You ARE probably right about the bridge shot, it must be open circuit since those big caps are only in parallel with line.

[Agent24]

Re: 35x30mm 450V 150uF replacement

Can you post photos of the capacitors in question?

I'm starting to think you mean they have vented, rather than exploded... you would have heard them if they had literally exploded.

[rustytierod]

Re: 35x30mm 450V 150uF replacement

Can you post photos of the capacitors in question?

I'm starting to think you mean they have vented, rather than exploded... you would have heard them if they had literally exploded.

Your right, looks like one leaked in the direction of gravity.

[budm]

Re: 35x30mm 450V 150uF replacement

Just SAMWHA caps that failed.

[Agent24]

Re: 35x30mm 450V 150uF replacement

Yeah those haven't exploded, or they would be in little pieces all over the inside of your TV. (Yes, it can happen!)

Clean the leaked electrolyte off the board, replace the capacitors. If the other output ones are Samwha too, or any other cheap brand, you should replace the lot at once.

[rustytierod]

Re: 35x30mm 450V 150uF replacement

Just SAMWHA caps that failed.

You can't see very well, but the little ones buldged too.

[rustytierod]

Re: 35x30mm 450V 150uF replacement

Replaced those 4 to start, no diff, 6 green flashes no back light or picture