Sanyo Flat Shutting down

[buddwisemonk]

Hi, I have a Sanyo 26" Flat screen
model DP26746
The problem Im having is a bit odd. I got the TV from a friends mother who said it just didnt work.... vague I know. I took it home. Plugged it in and I got a picture for about 2 minutes, then it shut off. If you press the power button after that, you can hear a "click" like its trying to come on then another "click" like its cutting off but it never gives you a picture and the LED power light does come on. after a couple of tries it will no longer make any sound. If you wait 10 mins or so the process can be repeated. Anyone have any Ideas. I was thinking power supply or replacing the board on that side. But I have no Idea where to get the board from. Any fix advice or part supply info is greatly needed and appreciated. I dont want to spend a ton fixing this thing.

 

[flat5]

Look for bad electrolytic capacitors in pulse power supplies.

 

[Nigel Goodwin]

Yes, high ESR capacitors are a VERY common cause of problems - if you're lucky, they might even be visibly bulging or leaking. Replace with 105 degree low ESR types.

 

[buddwisemonk]

Esr?

Sounds like an easy fix. Sorry I am new to this but. what does an ESR look like and how do i tell which one is bad? I have a meter if that helps. Also will i need a soldering iron? Thanks for your help.

 

[Nigel Goodwin]

Sorry I am new to this but. what is a ESR and how do i tell which one? Ihave a meter if that helps. THanks for your help.

ESR is "Effective Series Resistance", and you need an ESR meter to test it - or you can check for ripple using a scope - it's been the main cause of faults for many years now.

But for a start look for bulging electrolytics.

 

[Mickster]

For an idea of what to look for....

Capacitor Lab - Visual Signs of Capacitor Failure - Bulging and Leaking

....should give you a start.

 

[crutschow]

An electrolytic (generally in a relatively big tubular can which may have some writing on it like 470µF) may also be leaky as well as having a high ESR. Either way, they will often get hot so you might check for that after the TV's been on and quits operating. Unplug the TV before you poke around with your fingers.

If you need to replace it, you will need a soldering iron and someone who's familar with soldering.

 

[buddwisemonk]

I found two 105's that seem to be bulging at the top. I'm going to try to find a place to buy some today and replace them. Wish me luck. Thanks again guys and girls I really am grateful.

 

[Nigel Goodwin]

I found two 105's that seem to be bulging at the top. I'm going to try to find a place to buy some today and replace them. Wish me luck. Thanks again guys and girls I really am grateful.

105 will be the temperature rating, NOT the value - you need to check the capacitance and voltage required, ensure you get 105 degree ones (not 85 degree ones - which were more common), and preferably low ESR ones.

 

[buddwisemonk]

It seems the only 820 uf 200v 105 C , I could find is in CA...hoping to find one at a local radio shack. anyone know of another place to get these? It seems these are rare...also is there another Value that will work Like 800 uf 200v 105C or is it a must replace with same kind of deal?

 

[crutschow]

800µF should be ok (although that's not a standard size) but you shouldn't go much smaller. Larger is also ok.

 

[buddwisemonk]

so would a 1000uf 200V 105 work?

 

[Nigel Goodwin]

so would a 1000uf 200V 105 work?

Yes, the tolerance on electrolytics is HUGE - often something like -25%/+50%.

 

[Mickster]

It would be advisable to change not only the bulging capacitors, but all those from the same manufacturer. There are some known names which are particularly likely to fail, from the perspective of technicians who regularly deal with them. (Please read the second post too):

Badcaps Forums - List of Bad Cap Manufacturers

HTH.

 

[buddwisemonk]

now what? =(

I just replaced the 2 bulging ESR with 820 uf 200v 105C and I still have the same problem. anymore ideas?

 

[flat5]

Look for more bad caps.
Sorry you are having trouble.

 

[crutschow]

Also a bad cap could have cause something else to blow, like a rectifier.

Is there any possiblity of your getting a schematic for the TV?

 

[buddwisemonk]

Thanks for the reply will see if I can find a schematic and locate the rectifier. One more question. When the TV is powering up ..what is the "click" i hear when it powers off.

 

[Nigel Goodwin]

A relay, probably switching power to the mains PSU.

 

[buddwisemonk]

I can't seem to find a schematic for the board and Im also having trouble even locating a picture of a rectifier...what should I be looking for. And how do I tell if its bad?