Sonic'

Got a Plasma yesterday for free Vision PM4230

Wasn't sure if it would work, so powered it on, connected up the cable box, and voilla a picture

However the picture looked like it had a slight green cast to it (like moving pixels behind certain parts of the image)

Left it on for about an hour or so and noticed the bottom half of the screen was noticeably darker than the top half, and it started to get a red cast along with the green cast

Anyway about an hour later the screen suddenly went off and that tell tale smell of burning components

Took the back off it tonight and found the problem, what looks like a capacitor marked 3C 033 has pretty much melted

Ive circled it in the pic below



Anyway can this cap be replaced ( I can do it if I can source one) however Im not sure if it is the primary cause or secondary cause of the fault

On that particular board it has the RAMP UP and RAMP DOWN circuitry on it

the TV does still power up and fans come on, and goes to fire the screen up and then shuts down

jods

Surely just take it back for a full refund?

Or did you buy if off a mate of a mate ? In which case - Tough ****.

Odds on

[Fully qualified tv repair man]Yeah, *sucks teeth* you need a new capacitor mate. Tsk *shakes head* Pricey those bits. [/]

Sonic'

I got it for FREE

Tam the bam

Try Maplin for capacitors

Maplin > capacitor 3C 033

jods

Bonus In that case I feel no pity for you :P

Sonic'

I can probably get a Cap, its just if I replace it it may well just go again, as I dont know if that was the primary cause, or the screen going funny being the cause and blowing the Cap

I *may* be able to get another board, or another unit with different issues to make 1 from 2

Bug Eyed Peas

Don`t you know it invalidates the warranty if you open it up?

But if it was gratis, wth.

Luminous

iTrader: (3)

Maplins normally have some techy spod in there who knows their stuff. Don't mention getting the TV free or he may get all jealous on you. Take a really good close up picture of the component, and also note down all the writing you can see on some paper. You should be able to source what you need

[expert diagnosis mode on]
If it goes bang again, then you will know its the secondary cause of your problems

Luminous

iTrader: (3)

I bet you are feeling smug

Beating me to the answer, and providing the link

Tam the bam

Hell yeah!

Odds on

Ahh, but I confirmed it was a capacitor

Tam the bam

I have the urge to use the infractor 3000

Luminous

iTrader: (3)

pffftt, call that a weapon Its the Tesla gun you need to look out for

Sonic'

So will I if the TV blows again

Cheers for the link, it just so happens I am going past Maplins tomorrow too

AndyC_772

iTrader: (2)

Do people still use the word 'spod' once they've left school?

It's hard to tell from the photo, but it looks more like an inductor to me than a capacitor - sort of hourglass shaped, like the row of similar components next to the silver heatsink?

If so, it's not going to be the primary cause of failure. An inductor is just a coil of copper wire wound on a former - there's nothing to fail in the first place. If the outer plastic sleeve has melted, something has caused a massive over-current to flow through it, turning it into a little electric heater.

"3C 033" doesn't mean anything on its own - my best guess is it may mean the value is 3nH. But I'd bet you a beer that replacing it won't fix the TV

Luminous

iTrader: (3)

Yes, some people still do use the word spod after leaving school

davegtt

I'll bet you a beer it will fix it for half hour before it goes again

Odds on

See, I told you it wasn't a capacitor







Sorry sonic, their not being much help here are they.

Sonic'

Sounds about right Andy, there is one other on the right hand side of the board and is the same (although not melted )

Ive just had another look and it has literally heated up and melted (probably took it about an hour or so as thats how long the TV was on for)

It is virtually the same as the other ones in the row, they are labelled 3C 021 and are 19.0uF or might be 190uF

This one is 3C 033 stamped on the top, and is labelled as 220A BA and made by Felix

I am assuming that it is the secondary cause, there is a scratch on the front of the screen, but it hasnt penetrated through, and didnt have any issues around the scratch when it was on

Sonic'

More than likely, I aint replacing one of those every half hour, kids will just have to colour some books instead

AndyC_772

iTrader: (2)

You're on!

It's VERY hard to completely wreck an inductor; first the outer insulating sleeve melts (and smells bad), then it'll desolder itself from the board. Something else will inevitably die before it actually manages to melt a coil of copper wire!

Sonic'

It does actually seem intact around the solder joints, and the copper wires are still attached, it has literally just 'taken its jacket off' due to getting a major sweat on

No doubt something else has caused it but foof knows what

On the board next to it, it has 4 LED's (mini mini ones) and one of them lights up when you turn on the TV, then the one next to it flashes on and off repeatedly (they look like they are marked D1 D2 D3 D4)

Everything is modular in there, but it depends on which board/module has failed, as I may be able to source another with a different fault

AndyC_772

iTrader: (2)

More likely it's just an innocent victim of the real fault. Just because the outer plastic sleeve has melted doesn't mean it's not working - TBH it probably doesn't even need replacing.

It looks like a power supply board to me; my guess is that a transistor somewhere has gone short circuit. That could cause all manner of power supply problems - which might explain the odd symptoms prior to the failure - as well as the excessive heating in the inductor.

If you feel like having a go at it yourself, it's probably worth making some effort to get hold of the service manual, which will include a parts list. You should be able to get any spares you need from rswww.com or www.farnell.co.uk or Digi-Key Corporation - United Kingdom Home Page - or, alternatively do what I'd do and take it into a repair shop. It shouldn't be expensive if it's just a transistor and some minor collateral damage.

Sonic'

I may be able to get hold of a service manaul

Now a little history about this TV, It was installed in a Pub, the Pub complained about the green cast, so it was swapped out for a new one

The TV got looked at (not sure by who) who said they couldn't repair the green cast, so was destined for the skip

hence me getting it, now there is a sticker on the back saying TV Powers up but no screen, thats all it says

Which is pretty much what it is doing now, but it did work when we first plugged it in, but the picture did deteriate into the greenish cast farily quickly, then 3 horizontal lines, then the bottom half of the screen going very dark then 'pop'

[Davey]

Alot of plasmas seem to have low life cap's.. I just fixed a Philips by replacing 3 caps on the board that had been fried.. its a a sad state of affairs really taht modern technology can be so ****e.

AndyC_772

iTrader: (2)

Rated lifetime on even a good electrolytic capacitor at its maximum operating temperature can be as low as 2000 hours!

Normally they last a lot longer; capacitor lifetime roughly doubles for every 10 degrees cooler it runs. But combine the fact that plasma TVs get hot with the fact people don't want a powerful cooling fan in their living room, and it's going to cook up in there. So the PSU will fail.

Tart Man

K a capcitor blew. So that's the symptom:

Now to for the hard part: finding out what caused it to blow.

Usually need in excess of 50 odd volts of ac current to get an average sized 32v one to start melting.

100volts a/c to explode it

Sonic'

I thought this was now an inductor not a capacitor

It does look intact minus its plastic coating, but it does smell when you turn the TV on, so it still must be getting a fair amount through it making it heat up so much in a few seconds

everything else looks clean so may be difficult to diagnose the cause without any kind of testing equiment, and a multimeter (albeit a posh one) is all I have

Tart Man

On second look, yes it looks like an inductor.

Use a camera with a macro function next time