Samsung LE26R88BD Strange Fault (Main Board??)

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Hi
Got this Sammy and it is doing a strange fault.

When cold the tv works fine then after 10 minutes the TV shuts down, when shutting down the backlights flash and it gives the impression the screen tabs need reseating...The TV will then turn itself back on and work for approx 1 minute and the whole process will start again, where it will shut down and give the impression of tab bonding fault

The strange bit is that if I turn on blue screen the tv will sit and work fine...been running for 1 hour now no problems
If I turn blue screen off and just put analogue channel and go mad watching static the tv will not fault

If I plug in a hdmi connection with moving images the tv faults, when it is on DTV from cold it will work fine, once the fault starts the DTV will never come back on just a blank flickering screen...let it go cold again DTV works fine for 10minutes

I have unplugged the T con and Inverter and the fault still persists, I also spotted that RM801 had little black specs on, looking through other posts this is a common fault, changed that to be on the save side.

So to put it short the tv is only shutting down when it is processing moving images on the screen..if that makes sense

The main board is BN41--00813

Thanks in advance

[tom66]

Re: Samsung LE26R88BD Strange Fault (Main Board??)

These boards do have quite a few problems with bad caps. Have you ruled them out?

[signup]

Re: Samsung LE26R88BD Strange Fault (Main Board??)

Cheers Tom, sorry did you mean the caps in the psu?

[tom66]

Re: Samsung LE26R88BD Strange Fault (Main Board??)

Yep.

[signup]

Re: Samsung LE26R88BD Strange Fault (Main Board??)

Right OK I will start with the ones they sell in the repair kits CM860, CM851, CM852

[tom66]

Re: Samsung LE26R88BD Strange Fault (Main Board??)

Or you could check the power supply voltages and see if they are OK. If they are OK, they are not the fault. Just because I said they may be at fault doesn't mean they are actually the cause.

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Re: Samsung LE26R88BD Strange Fault (Main Board??)

Hi, I have changed the caps and still the same, here is a video of what the tv is doing...it has now started doing it on blue screen now too

http://www.youtube.com/watch?v=XiNjhDXOCHE

The only voltage that dips when the fault occurs is the 5.3v line which drops to 3v and then instantly stabilises at 5.3v

What is the best way to confirm/rule out the main on this set

Cheers

[tom66]

Re: Samsung LE26R88BD Strange Fault (Main Board??)

A 5.3V line dropping even temporarily to 3V is indicative of a fault, likely on the power board though potentially a bad main board with intermittent short could cause this -- try tapping/heating etc see if problem comes back faster.

[signup]

Re: Samsung LE26R88BD Strange Fault (Main Board??)

A 5.3V line dropping even temporarily to 3V is indicative of a fault, likely on the power board though potentially a bad main board with intermittent short could cause this -- try tapping/heating etc see if problem comes back faster.

Cheers tom the question is what is making it dip to 3v..PSU or main

on/off pin of the psu stays constant at 5.1v when the fault is happening

I have also noticed a couple of the IC's on the main are getting very hot after around 30 seconds of the tv being on

[tom66]

Re: Samsung LE26R88BD Strange Fault (Main Board??)

I haven't the slightest clue. But I'd take a gander that you might have a power supply which cannot power the main board or a main board drawing more power than the power supply is nominally rated for.

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Re: Samsung LE26R88BD Strange Fault (Main Board??)

Errrmmm so sorry, I need to pay more attention, and look more closely at the boards when checking, I have just spotted a nice rust patches and what looks like water/fluid damage on the main. All under the metal sheilding that looks like a pain in the arse to get off...A new main it is I am not chasing tails to resolve this one

Thanks again Tom

[signup]

Re: Samsung LE26R88BD Strange Fault FIXED

Decided to stop being a wuss when it comes to main boards and did a little more investigation, checked the voltages on the VR's on the underside of the board and found 2 giving funny readings when the fault was happening, against when the TV was working

Board PN= BN41-00813B-MP

IC positions IC1107 & IC1106

Both Voltage regulators were labelled 1117 07152L

Replaced and the TV has been playing for 5 hours now and not a hiccup

[tom66]

Re: Samsung LE26R88BD Strange Fault (Main Board??)

That's nice to hear. Thanks for the feedback.

[signup]

Re: Samsung LE26R88BD Strange Fault (Main Board??)

No problems, hope it help someone else who has the problem...why has your name turned green tom

[tom66]

Re: Samsung LE26R88BD Strange Fault (Main Board??)

Anyone over 100 posts gets a green name.

[beavisthelizard]

Re: Samsung LE26R88BD Strange Fault (Main Board??)

Hey nice to know there's an answer to this one...

I tried resetting the eeprom, changes caps...

Was looking at ordering a new main board (35pound) but where did you manage to track down the IC's from?

I've run a few search's on different sites but If you could speed things up that would be great.

I've got a Samsung LE23R88BD when it feels like it...(warmed up) Screen freezes, pix-elates goes white, black-off and starts again.

[jpalmeida]

Re: Samsung LE26R88BD Strange Fault (Main Board??)

Hi signup!
Thanks for your share.
I have the same board BN41-00813B but in other SAMSUNG, with the same problem.
I'll see if it works for me too.
Thanks in advance.
Joao Almeida
Portugal

[jpalmeida]

Re: Samsung LE26R88BD Strange Fault (Main Board??)

Signup, I can't find those IC's.
Where are them located in the board?
I only see two SMD IC's IC1109 and IC1109 both 17-33 06524L, that seemed to be the same regualtors of 3,3V.

[selldoor]

Re: Samsung LE26R88BD Strange Fault (Main Board??)

I believe there are more than one version of this board.
You need to post good clear pictures of YOUR board in your other thread then we might be able to help

[jpalmeida]

Re: Samsung LE26R88BD Strange Fault (Main Board??)

This is the Samsung I am talking about:
LE40M87BDX/XEC
Yesterday it was more than 5 hours running well (no back cover). Well, even with cover, here it never showed the problem. I saw the problem at the client's home.
Hope Signup can tell me where IC positions IC1107 & IC1106 are.

Wish you all a very Happy New Year 2014.

Best regards.
Joao Almeida