Samsung TV cycles On to Off

[gaztoo]

The TV is a Model LA32R81BD 32" LCD.

After turn on from Standby it runs for about 5 mins then begins to cycle from On to Off - the red Standby Led flashes while in the Off state - No Pic or sound - but the Blue panel below the Samsung name is lit .

After reading previous posts on this problem I have replaced all electros on the power supply board - even though none were visibly suspect, they were all Sanwha brand.

I have disconnected the backlight inverter board from the Power board, but this has no effect on the fault.

I have directed a fan onto the boards but this has no effect on the fault or the On to Off period.

In the OFF state the 5.4v, 12v, 13v and 24v rails all drop out briefly.
The SB 5.2v remains stable.

On the PS pin of CNW801 socket the voltage is 3.3v when On and 0v when Off.

Any leads would be welcome.

Gaz

[jdre]

Re: Samsung TV cycles On to Off

I have just repaired a Samsung Plasma, it did the same thing, resolder any poor or cracked connections you can see on the Power supply board. Mine clicked off, back on, or just clicked. Hope that helps.

[gaztoo]

Re: Samsung TV cycles On to Off

Hi jdre

Many thanks for taking the time to give your input on my problem.
I did omit to note in my original post that the first thing that I did was to go over the PSU board with a magnifying glass and solder iron which, of course, in my case did not fix the problem.

Gaz

[Toasty]

Re: Samsung TV cycles On to Off

What brand / series did you replace them with?

[kc8adu]

Re: Samsung TV cycles On to Off

we need to find out if the psu is dieing or the logic is commanding it off.
did you try to pull up that pin that is 3.3 with the set on?

[gaztoo]

Re: Samsung TV cycles On to Off

Toasty - The caps were a mixture of "Suntan" and "Samxon" brands. Thanks.

kc8adu - I have called a halt on the set and sent it to the Samsung hospital...
I will post a final diagnosis when I know.

Thanks to all,
gaz

[Toasty]

Re: Samsung TV cycles On to Off

Series of caps was requested to see if correct ones were used for SMPS.

Suntan's are questionable. Samxon if newer stock are fine.

Hope you don't get by Samsung repair.

Toast

[nasdat]

Re: Samsung TV cycles On to Off

some lore from the last of the samsung 30" & 27" crt owner's experience may prove helpful to someone ~ apparently some of these won't degauss unless plugged into a 'quality' surge protector (was this way with [1] of [2] of mine) methinks perhaps
that the quality of relays delivered is suffering due to pricing pressures {lawd only knows what's happened to Samsung USA customer service and hope they get their act back together before it's too late}

[gaztoo]

Re: Samsung TV cycles On to Off

The set was fixed with the replacement of the "Main" PCB - there are only two boards, PSU and Main. Toasty - it was painless! Thanks for your posts.

Gaz

[Toasty]

Re: Samsung TV cycles On to Off

$$ Cost?

That was relatively quick too.

Glad you're fixed and satisfied!


Toast

[Wizard]

Re: Samsung TV cycles On to Off

Typically 200 for a mainboard if customer bought themselves but samsung wants them back as core so it has core fee applied.

What kind of capacitors replaced the samwha capacitors? We wanted to make sure you did right job.

Cheers, Wizard

[gaztoo]

Re: Samsung TV cycles On to Off

Wizard - See my reply #6 for the caps that were used.

Cheers, gaz