Questions about a Vizio VW42L FHDTV10A

[Spork Schivago]

Hello. I have a Vizio VW42L FHDTV10A that had a bad cap on the power board. I replaced that but noticed on the inverter board (I could only find one on this model), there where three bad caps near four MOSFETs (I believe). All three have blown bottoms, pushed up tops, etc. One of them appeared to leak dielectric (I think) all over the board. Is this something I should clean up? It seems pretty caked on.

Also, I've seen people who have had bad MOSFETs on their inverter boards for this make and model TV, however, their design is a bit different. The inverter board model number is 6632L-0481A. Does anyone know how I can check these four MOSFETs? Thanks.

[Spork Schivago]

Re: Questions about a Vizio VW42L FHDTV10A

Whoops, forgot some pics. Sorry about the quality. It appears it's the best we can get right now. If you guys need to see something better like, let me know and I'll try in a different room with different lighting or I'll try using the cell phone which has flash. It was hard to add lighting because it was reflecting on the tinned lines real bad.

The three bad caps are shown in multiple images. I tried zooming in as much as possible and taking multiple images so it'd get everything. Sorry if it's a bit hard to follow. I can take one big image of the whole board if you guys want.

[diif]

Re: Questions about a Vizio VW42L FHDTV10A

IPA and a non static brush should clean it up.
The design is similar to a TV with a faulty shorted inverter i am working on at present. Identical MOSFETs and caps (changed by previous owner) I tested for shorts between the pins on each of the legs and although one showed as short I removed and it wasn't . I strongly suspect it's BD9897FS (the IC in photo 2) as they are sold in ebay repair kits along with the MOSFETs (for my board).

[jetadm123]

Re: Questions about a Vizio VW42L FHDTV10A

If any of the mosfets did short out, then you might also want to check the fuse to verify it didn't blow.

[Spork Schivago]

Re: Questions about a Vizio VW42L FHDTV10A

Thank you Diif. I tested between each pin on the MOSFETs (left leg with middle, middle with right) and the resistance is in the mega ohm range so I'm assuming they're okay? The middle one shows 0.000 ohm resistance when I test with the fat pin in the back, which I believe it's supposed to. So that's good. A few of the left / right pins, when I checked the continuity with the back fat tab, showed low resistance at first, like 300 kOhm, very sparatic, jumping around a bit, and then going into the mega ohms. I was thinking maybe the bad caps was causing this to happen?

[Spork Schivago]

Re: Questions about a Vizio VW42L FHDTV10A

If any of the mosfets did short out, then you might also want to check the fuse to verify it didn't blow.

Good call on the fuses Jetadm123! Both fuses turned out to be fine (the fuse on the power board and the SMD fuse on the inverter). It would of been pretty foolish of me not to check them though! The guy just said it stopped working. He didn't say anything about lightning or anything. Wife didn't really ask him much.

Does anyone have any idea what would make all three caps on the inverter to blow like that? Are they wired in series or something and when one blew, it blew the others? I didn't test all the ones on the power board, just replaced the one bad one that I could tell by looking at it. It'd a real pain to get to them because of this heat sink but in order to remove the heat sink, I need to remove the transformer.

[diif]

Re: Questions about a Vizio VW42L FHDTV10A

I think the caps failed due to heat and a poor brand. The ones on my board have already been changed, they seem to be a fairly common problem though. My board is a 6632L-0449A and has the same value caps and identical MOSFETs.

[Spork Schivago]

Re: Questions about a Vizio VW42L FHDTV10A

I think the caps failed due to heat and a poor brand. The ones on my board have already been changed, they seem to be a fairly common problem though. My board is a 6632L-0449A and has the same value caps and identical MOSFETs.

Okay. Makes me think I should probably replace all the bad ones on the power supply. The guy doesn't want to go over 100$ for the repair though. For the ones on the inverter, can I just use any decent cap or do I need something special? Like ultra low ESR or high ripple current or something funky like that?

[102mm]

Re: Questions about a Vizio VW42L FHDTV10A

My favorite TV to repair! same problem every time.. Capacitors and voltage regulators..

[diif]

Re: Questions about a Vizio VW42L FHDTV10A

I always use Panasonic FR FM and FC for my repairs after a recommendation on here, but anything decent should do. I don't think they need to be anything special.

[Spork Schivago]

Re: Questions about a Vizio VW42L FHDTV10A

My favorite TV to repair! same problem every time.. Capacitors and voltage regulators..

Got any suggestions on which voltage regulators I might want to have a look at? Thanks.

[Spork Schivago]

Re: Questions about a Vizio VW42L FHDTV10A

I always use Panasonic FR FM and FC for my repairs after a recommendation on here, but anything decent should do. I don't think they need to be anything special.

So Panasonic FR, FM or FC are good? I always liked those RubyCon ones personally. I'll have a look at Digikey to see what I can find. Shipping and taxes are a bit high. I'd like to get a decent collection of caps going. I got a few. I wonder what would be some of the more common types out there. 330uf, 680uf...25v, 35v, 50v. I have a lot of the 4.7 variants, like 4.7uf, 47uf, 470uf, etc. Got a few of the 2.2uf variants as well.

[budm]

Re: Questions about a Vizio VW42L FHDTV10A

Panasonic is all I use for my repairs.

[diif]

Re: Questions about a Vizio VW42L FHDTV10A

^ yes it was this man/wizard that suggested i use Panasonic. Cheers budm.

[Spork Schivago]

Re: Questions about a Vizio VW42L FHDTV10A

Panasonic is all I use for my repairs.

So Panasonic are generally better than RubyCon? I'll switch. I do have to admit, I haven't really been able to work on learning more about circuit board design and everything. I haven't really had the time. My mum is dying of Chronic Kidney Disease. I want to give her one of mine but so far, she's against it. Keeps saying I might need it one of these days.

Anyway, I'm looking at the EEU-FR1V681 Panasonic capacitor. Does anyone know what's the difference, besides price, between the EEU-FR1V681, EEU-FR1V681B, EEU-FR1V681L and the EEU-FR1V681LB? I couldn't really find anything on them. I see the L and LB ones have a higher ripple current and a lower impedance. They're a bit taller as well. The L and LB look identical as far as I can tell. The EEU-FR1V681 and the EEU-FR1V681B look identical as well.

http://www.digikey.com/product-searc...itor+680uf+35v

[budm]

Re: Questions about a Vizio VW42L FHDTV10A

'B' for Alternate packaging Box & Tape for large Qty. 500 pieces minimum order.
'L' is for 27mm Height.
Without 'L' is 22mm Height.

You want to get the 'Bulk' or 'CUT TAPE (more expensive)' so you can order just 1 or more instead.

[Spork Schivago]

Re: Questions about a Vizio VW42L FHDTV10A

'B' for Alternate packaging Box & Tape for large Qty. 500 pieces minimum order.
'L' is for 27mm Height.
Without 'L' is 22mm Height.

You want to get the 'Bulk' or 'CUT TAPE (more expensive)' so you can order just 1 or more instead.

Ahh! Thank you. And any of those Panasonic ones I listed are good, right? I don't need the higher ripple current / lower impedance ones, right? Or are they worth the little extra bit of money? I only need 3 but I'll probably order 6 in case I run into this problem in the future. Do caps have a really long shelf life?

[budm]

Re: Questions about a Vizio VW42L FHDTV10A

'FR' is Low Z type cap, it is the newer series than the FM/FC series, and it has longer life, 10K Hours.

[Spork Schivago]

Re: Questions about a Vizio VW42L FHDTV10A

Thanks Budm! Glad you're feeling better.