dell w3707c just a amber light on, Burnt caps pics inside!

[gordesky1]

Hello guys Im pretty much copying and pasteing this what i asked on avs forums which so far i haven't got any answers so i figure i try you guys




So today i found tv again that someone thrown out, Was hoping to be lucky that it will work but nope..

When the power button is pushed the amber light will come on and that's it.

Its suppose to turn blue when on. And when unplugging it and plugging it back in the amber light will blink 5 times.

So i figured i take it apart and see whats up cause i herd power supply's with bad caps are a known issues with lcds.

So after taking the psu heat shield off, There seems to be about 3 burnt caps under the heat sink on the secondary psu side.

I attached some pics of them.

Also i got some light on the panel to show after pushing the button a good bit which ony lit for about 2 secs. I also hear a faint clicking on each side of the panel i guess the inverters or the back lit is trying to come on? The power supply also makes a faint noise also.

So pretty much if i buy a new power supply for this will the tv work? Can the bad caps cause any more damage to the tv?

Cause i can get a used psu on ebay for about 35$ or a new one for 45$ Which isn't bad at all if i can get this tv working again.

Or i can try and soder new caps in sense it wont hurt trying anyways. Ony thing im worrying about is getting shocked.

Thanks

[bammbammfran]

Re: dell w3707c just a amber light on, Burnt caps pics inside!

a used ebay one might not last too long since obviously caps on these aren't so hot

If you have the ability, I would start by changing the caps on this one since you do have a little power in it so it is not totally cooked.

[gordesky1]

Re: dell w3707c just a amber light on, Burnt caps pics inside!

They do have a new one on there for 45$ but it would much better to spend couple $s and put the caps on myself.

I can soder a bit not the best tho, But mostly what im worrying about is getting shocked lol

I Herd you can get a deadly shock from theses even when off. like i know not to touch the coils and stuff, But what about when i un soder them? Is it safe?

thanks.

[Th3_uN1Qu3]

Re: dell w3707c just a amber light on, Burnt caps pics inside!

Don't touch the big capacitor and you will be fine. A small supply like that cannot deliver a harmful shock, just don't have sharp objects nearby...

PSUs from large LCD or plasma TVs are more dangerous.

[SteveNielsen]

Re: dell w3707c just a amber light on, Burnt caps pics inside!

You can discharge the big caps before removing them if you're worried but these ones I would not be concerned about a shock hazard from as long as the power is off of course

[truep]

Re: dell w3707c just a amber light on, Burnt caps pics inside!

As long as you stay away from the large 450V cap on the hot side, you won't get shocked. The cold side where those caps are, are 24V max. No shock there. You can discharge the big one on the hot side by shorting with a screwdriver.

[budm]

Re: dell w3707c just a amber light on, Burnt caps pics inside!

I would discharge the big cap in the primary side with bleeder resistor (20K 5W), that cap will have about 400VDc on it.

[jose6326]

Re: dell w3707c just a amber light on, Burnt caps pics inside!

I would replace the caps first

it will probably only cost $8 with shipping from Digikey

[gordesky1]

Re: dell w3707c just a amber light on, Burnt caps pics inside!

Thanks guys Will give it a try and replace the caps.

Does radio shack have caps that will work on this? Would like to get them local if i can sense i would like to get going on this fast lol..

And will a 40watt soldering iron be good enough?


Oh and also on one of thoes pics i posted i notice a burnt spot on a metal thing by the caps. Will this be a problem?

Heres the pic with a black circle around it.

[ivoh]

Re: dell w3707c just a amber light on, Burnt caps pics inside!

look at the underside and everywhere else on the board for more damage. The caps you get as a replacement should have equal or greater voltage/farad values. if the caps are the only obvious damage, id start by replacing them

[budm]

Re: dell w3707c just a amber light on, Burnt caps pics inside!

It looks like the SMD on the bottom side of the board may have over heat or burnt up, post good clear pictures straight shots of top and bottom side of the board.
You need to get low ESR type capacitors, not the general purpose type from RadioShack.

[gordesky1]

Re: dell w3707c just a amber light on, Burnt caps pics inside!

Heres more pics of the board. And close up ones. Hopefully they clear enough.

So far i really don't see any other damage other than those caps. But i leave it up to the pros to decide

[gordesky1]

Re: dell w3707c just a amber light on, Burnt caps pics inside!

Does anyone see a problem other than the burnt caps?

[stj]

Re: dell w3707c just a amber light on, Burnt caps pics inside!

what does it say on those caps.
it looks like 35v and KZH but i cant see the rest.
and how wide & tall are they?

[crt man]

Re: dell w3707c just a amber light on, Burnt caps pics inside!

Hi
You need to post pictures, of the soldered
print on the underside of the PSU to get a better
idea, if there is a problem with the SMD components
on that side.

Alan.

[gordesky1]

Re: dell w3707c just a amber light on, Burnt caps pics inside!

Sorry it took long to post back on this project. Had to do other fixes hehe

Here's better pics, And also took the top metal heat sink shield off the psu and underside.

So far by looking at it, It seems like the ony damage i see is the burnt and swollen caps, But really not sure. need the experts for that


I figure i try and get this one going sense so far i fixed a hans g 28inch couple days ago by replacing the 2 caps that budm said to replace. Using that same monitor as i type this

soldering in caps isn't really as bad as i thought it would be.

Let me know if the pics is good enough.


added 4 more pics i decided to un solder them to get a better look.

[gordesky1]

Re: dell w3707c just a amber light on, Burnt caps pics inside!

So does everything look good other than the burnt caps?