Ps-50q96hd That went pop

[tom66]

Re: Ps-50q96hd That went pop

It looks like one of the voltages on the Y-main is bad. You should avoid running it for too long or the buffers could go bad. Disconnect the buffers then proceed to check the Vsc, Vsch and Vset voltages.

[tw2005]

Re: Ps-50q96hd That went pop

Not saying this is the case here but have you messed with any trimpot adjustments on any of the boards?

Here's an example of what happens if they are way out on an old LG I got after someone had touched it. before and after

Nothing replaced, but all Ysus pots had been messed with .

[smiddy1980]

Re: Ps-50q96hd That went pop

I am getting the correct voltage from the power board but I am sure Tom is right with the other voltage on the yboard on some of the pins I am getting -88 v and I think it should be between 90 and 120 what could be causing the -89 and idea ?

[tw2005]

Re: Ps-50q96hd That went pop

I put the doc here to make it easy for anyone to refer to since this is what you're using.

I've never tried any of this and had no dramas with mine, I had simple replacement of 88N30W fets only + buffer

[smiddy1980]

Re: Ps-50q96hd That went pop

Thanks TW2005 my voltages are no where like in the doc, I don't get any voltage out of pin 13 and the other pin are all around -88, I have replace c5709, c5300,c5715, Q5302,Q5303,Q5304,Q5306,Q5500,Q5501 ZD5502, it may be my bad soldering, could my bad soldering cause this strange voltage?

[tom66]

Re: Ps-50q96hd That went pop

What point are you using as your meter ground? (black lead)

[smiddy1980]

Re: Ps-50q96hd That went pop

yes, on top of heatsync and red lead to test pins

[smiddy1980]

Re: Ps-50q96hd That went pop

here are my readings pin 25 -88v, 23 -86v, 21 -85v, 19 -88v, 17 -89v 15 -88v, 13 0v

[smiddy1980]

Re: Ps-50q96hd That went pop

just tested the vscan voltage and getting -189 this is lower that the 208 at the top of the board, think this is where the problem lies ?

[tw2005]

Re: Ps-50q96hd That went pop

Post a pic of the label on the back of panel

[smiddy1980]

Re: Ps-50q96hd That went pop

Pic of the post on the yboard

[tw2005]

Re: Ps-50q96hd That went pop

Pic of the post on the yboard

Right, so have a look at the sticker and did you see the -190Vsc?

that is Vscan and that is what you need to reference your -189V to

[smiddy1980]

Re: Ps-50q96hd That went pop

so I need to move the Vsan pot to I get -190v?

[tw2005]

Re: Ps-50q96hd That went pop

so I need to move the Vsan pot to I get -190v?

At this point don't touch a thing yet. If you have a fine tip permanent marker, grab it as I'm just looking at the pots and we'll need to mark it's current location prior to moving them. That's on the Ymain.
I have serious concerns with the B20NK50Z smd fet. what wattage iron have you got?

[smiddy1980]

Re: Ps-50q96hd That went pop

not sure on the wattage, you think I may have damaged it ?

[tw2005]

Re: Ps-50q96hd That went pop

On the ymain

leave Yset alone

Yfr long, marke the arrow pointer and then mark a rference point for it on the board or pot housing to come back to if need be.

Then adjust to match this photo. I'm still checking more of the board, start with this.

[tw2005]

Re: Ps-50q96hd That went pop

not sure on the wattage, you think I may have damaged it ?

I'm worried it's not soldered well and could be dry joint. What brand and model iron then if you don't know. Either way looks like it needed more heat

[tw2005]

Re: Ps-50q96hd That went pop

The last pot VR5800, leave.

Try that and fire the TV up and see if we got lucky

[smiddy1980]

Re: Ps-50q96hd That went pop

no still the same, didn't look like it mad any difference

[tw2005]

Re: Ps-50q96hd That went pop

no still the same, didn't look like it mad any difference

well the fact no change at all suggests part of the ymain is not right. that was a fair way out.

I don't know, I can't see all your repairs, get a meter and confirm the smd fet is actually making connection on the heatsinkded body to pcb where it's soldered.

There's no schematics for these, that's why I love the panasonic gear, youget full diagrams.

Hopefully a Samsung guru will pop their head up, I really don't know.