Samsung Model LN40b630N1FXZA Repair

[BrewDudeColumbus]

Hello --

I have a Samsung Model LN40b630N1FXZA I am trying to repair for a co-worker.

Symptoms:

It will occasionally power on -- but will not stay on very long (10-15 minutes) -- and will not re-power on afterwards.

I purchased him a recap kit on ebay for the BN44-00264A Power Supply Board.
Which replaced the caps, QP801S, QP802S, and UP801s (Power factor correction chip).

Still same problem.
Probed around Power Supply voltages -- the +5VDC Standby looks good at 5.18V.
No main 5vdc or 13vdc -- which I know turns on when it gets ON signal from Main Board.
The ON signal form the Main Board (Board # BN94-02597U) is fluctuating from 0.89VDC to 0VDC -- it's not a steady 0.89V.

When I probed the TV while working (for a short time) -- all of the voltages were fine (+5, +13V, and ON signal).

At this point, I figure it to be the Main Board -- well, I was wrong after replacing the main board -- it still does the same thing.

So - thinking it is a power supply problem.

Any ideas or thoughts??

Thanks,

Rick

[budm]

Re: Samsung Model LN40b630N1FXZA Repair

'The ON signal form the Main Board (Board # BN94-02597U) is fluctuating from 0.89VDC to 0VDC -- it's not a steady 0.89V.' PS-ON <1V = OFF, >2V = ON, It is generated by the main board are you sure your replacement board is good?

[BrewDudeColumbus]

Re: Samsung Model LN40b630N1FXZA Repair

'The ON signal form the Main Board (Board # BN94-02597U) is fluctuating from 0.89VDC to 0VDC -- it's not a steady 0.89V.' PS-ON <1V = OFF, >2V = ON, It is generated by the main board are you sure your replacement board is good?

i received the main board from ShopJimmy today -- it is supposedly good.
Exhibits same problem as before.

I'll see if I can get TV to turn on again and re-measure PS-ON.

[BrewDudeColumbus]

Re: Samsung Model LN40b630N1FXZA Repair

Can't get the TV to turn on again.

Measuring the PS_ON again -- it is alternating between 0.89V and 0V -- at a rate of once a sec.