samsung hpt 5054xxaa

[tocold4u2]

Have all boards in except. upper buffer board. i have tested with dmm and have all the right numbers but the screen will flash on for a split second when powered on..with a bottom. half has like multi colors blue green red and white. and its distorted.
Could this be a bad main logic board ? I have a green light on logic board and y main . my camera is broke or i would post some pictures.
Buffers are new ..and y main is new
thanks for any tips /help

[tom66]

Re: samsung hpt 5054xxaa

You got both buffers in? Could be -Vsc or Vsch voltage fault.

[tocold4u2]

Re: samsung hpt 5054xxaa

No i just have lower buffer hooked up.

[tom66]

Re: samsung hpt 5054xxaa

That can happen with a working Y-main and lower buffer if the lower buffer is missing the drive signals that would normally be fed in via the upper buffer.

[tocold4u2]

Re: samsung hpt 5054xxaa

No just lower buffer is in. i have no response from powebutton on side of tv.
If i unhook the buffer board n leave the set run without lower buffer .

[tom66]

Re: samsung hpt 5054xxaa

So panel only lights briefly? Does a small light illuminate on Y-main, near the white ribbon cable?

[tocold4u2]

Re: samsung hpt 5054xxaa

Yes the sm light on y main lights up....i just had both buffers in but didnt have the tabs on the upper buffer. when i powered the set on. the two color band resisters on left side of. on y main started to glowing red hot so i killed power to the set

[tocold4u2]

Re: samsung hpt 5054xxaa

Im suprised i didnt blow a hole in buffer chip

[tom66]

Re: samsung hpt 5054xxaa

I think you might only have a bad Y-upper buffer if light doesn't light up and you get continuous video noise on bottom half, but if the noise is dropping out you could still have a fault on the Y-main.

[tocold4u2]

Re: samsung hpt 5054xxaa

Those 2 resisters shouldnt get red hott...i bet there is a fault on y main it was right where the upper n lower buffers boards come together at. y main

[tom66]

Re: samsung hpt 5054xxaa

I thought with only bottom in it was working? I am confused now.

[tocold4u2]

Re: samsung hpt 5054xxaa

With just the bottom one. hooked up..the pic. comes on for a split second when i powdr the tv up !. i then tried. the lower n upper buffer. but didnt have the tsps from panel. on upper buffer board.. n thats when those two resisters got red hot

[jettboat]

Re: samsung hpt 5054xxaa

The light on the y sus is a fault. remove buffers & check the ysc voltage should be -190 if I remember right. a +v will blow up good buffers quickly, had one of these the transformer was bad caused it. I have 4 of these boards usually easy fix but finding cheap buffers on a 720 tough

[tocold4u2]

Re: samsung hpt 5054xxaa

Ok thanks..i thought that livht ment you had proper voltages.

[splitcrete]

Re: samsung hpt 5054xxaa

I fixed 3 of those sets ,and all the same .Bad upper buffer ICs,Y-main mosfits. If you have a green led on your Y-Main you have a fault on Y-Main. I'm looking for my notes on that model when I find them I will post info. Oh all three when fixed had no (power off) on side of the set. The one in front worked so I didn't look for a problem with it.

[tocold4u2]

Re: samsung hpt 5054xxaa

i will check the y main for. bad mosfit..with the lower buffer taken off there is no green light on the y main

[tocold4u2]

Re: samsung hpt 5054xxaa

What would a bad mosfit measure ?? i think i may have 2

[tocold4u2]

Re: samsung hpt 5054xxaa

didn t find any

[tocold4u2]

Re: samsung hpt 5054xxaa

couldnt find any shorts ..but but lower buffer in the bottom half of screen has blk bar

[tom66]

Re: samsung hpt 5054xxaa

Looks like top half isn't sending signals to bottom half == bad top buffer board possibly.