Samsung LE40R88BDX/XEU

[xrazaa]

Hello, I have a samsung 40inch lcd tv, the problem I'm having is that the tv will randomly turn itself off and then on again repeatedly. So after doing some research in the web I thought I had found the solution (faulty/ puffed/ under voltaged capacitors) however, after taking the back off the tv and examining the power supply board it turns out the capacitors look normal?

I'm a complete newbie so your patience would be greatly appreciated.

 

[Sam Gangee]

Failing electrolytics sometimes exhibit a slight bulge on top or sometimes push the rubber bung out of the bottom slightly. It's not always easy to spot and may not be visible at all.

A professional repairer has an ESR meter, which can test capacitors - usually without the need to remove them from the PCB.

Otherwise, replace ALL the suspects. See

http://www.satcure.co.uk/reviews/satcure_blog_189.htm#samsung
http://www.satcure.co.uk/reviews/satcure_blog_171.htm#samsung
http://www.satcure.co.uk/accs/low_ESR_capacitors.htm

 

[Ricardus]

Hello, I have a samsung 40inch lcd tv, the problem I'm having is that the tv will randomly turn itself off and then on again repeatedly. So after doing some research in the web I thought I had found the solution (faulty/ puffed/ under voltaged capacitors) however, after taking the back off the tv and examining the power supply board it turns out the capacitors look normal?

I'm a complete newbie so your patience would be greatly appreciated.

Have you checked the remote control on/off button isnt stuck and checked the batteries?

 

[Lucid]

Because of the way certain components go through the working > intermittent > failed path, there are two test procedures you can perform that will help short cut the diagnosis time.

These are gross simplifications, but in general...

...intermittent capacitors often show failure symptoms when cold. That's why TVs with bad caps are hard to start, but once running they appear okay.

...intermittent silicon (transistors and ICs) will fail when warm but be okay when cold. That's what you see if the TV starts to go wrong wrong as it heats up but is okay when cold.

Applying heat or cooling is a simple way to provoke a response from these components. The tools required are simple. For heat, either a hair dryer or hot air/paint stripper gun. For cooling you need a can of freeze spray. Before going any further, the normal "don't be an idiot" caveats apply. Heating up components beyond their tolerances will damage or kill things. Equally, although freeze spray is safe to use, don't go spraying everything or overdoing it on the board. A momentary press of the nozzle is more than enough for diagnosis purposes.

Freeze spray can be bought from Maplin and online retailers.

Apply cooling to turn an intermittent piece of silicon in to good temporarily. Apply heat to turn an intermittent cap to faulty.

 

[xrazaa]

Hello, I have a samsung 40inch lcd tv, the problem I'm having is that the tv will randomly turn itself off and then on again repeatedly. So after doing some research in the web I thought I had found the solution (faulty/ puffed/ under voltaged capacitors) however, after taking the back off the tv and examining the power supply board it turns out the capacitors look normal?

I'm a complete newbie so your patience would be greatly appreciated.

Have you checked the remote control on/off button isnt stuck and checked the batteries?

This sounds so simple, but it's normally the small things. I'll open it up again when I get home ad see if any of the soft touch buttons are causing the issue's and if not then I will probably but the capacitors recommended by @SamGangee.

Would these suffice?
http://www.ebay.co.uk/itm/Low-ESR-1...mponents_Supplies_ET&var=&hash=item3ce2eb1cac

http://www.ebay.co.uk/itm/Low-ESR-1...mponents_Supplies_ET&var=&hash=item3cc77f32cf

Thank you all for taking your time to reply.

 

[Sam Gangee]

I gave you the link for capacitors. I wouldn't trust eBay because:

1. It's eBay and
2. The actual ESR value of the so-called "low ESR" capacitors isn't stated. So I suspect they aren't low ESR.
3. They aren't Panasonic capacitors.

Unfortunately, eBay is full of sellers offering parts that are in some way sub standard or fake. You think you are getting a bargain but actually you are opening a can of worms.