Insignia NS-P501Q-10A Plasma

[kevinm34232]

Samsung Chassis

VS and VA drop out when turned on. Removing the ribbon connector to Y-Main and the voltages stay up.

So I have a bad Y-Main, buffer or both.

Anyone know how to test this buffer for shorts? (LJ92-01691A)

[tom66]

Re: Insignia NS-P501Q-10A Plasma

A bad buffer would not cause Vs/Va to collapse.

[kevinm34232]

Re: Insignia NS-P501Q-10A Plasma

I think it's the Y-Main but I wanted to make sure buffers were good, and wanted to know which pins to check for shorts.

[tom66]

Re: Insignia NS-P501Q-10A Plasma

One connector will have a load of pins connected together on the PCB. Test from there to the buffer output connectors which go to the plasma panel (all 768) If you have a beep mode on your meter you can run it along quickly.

[kevinm34232]

Re: Insignia NS-P501Q-10A Plasma

Can you tell by the pics? pic 2 and 3 are top and bottom connectors respectively. Thanks!

[tom66]

Re: Insignia NS-P501Q-10A Plasma

CN5402 is your FLOATING GND output that you can test from.

[kevinm34232]

Re: Insignia NS-P501Q-10A Plasma

Thx it appears to be good then.

[kevinm34232]

Re: Insignia NS-P501Q-10A Plasma

I found a post somewhere else saying if there are no shorted FET's on the Y-Main to replace this part on the bottom of the Y-Main. Do you think that's a possibility?

[tom66]

Re: Insignia NS-P501Q-10A Plasma

Hmm, do you have steady -Vsc or VSCAN from the Y-main board (whilst the voltages Vs/Va are up?)

[kevinm34232]

Re: Insignia NS-P501Q-10A Plasma

Sorry I put it away already, I had to put in an order anyway so I ordered a couple of those IC's and will give it a try when it comes in.

[kevinm34232]

Re: Insignia NS-P501Q-10A Plasma

Ehh well I replaced that IC and still no go. VS voltage drops out when turned on. I don't see any obvious problems on the Y_Main, but is it likely this board that is bad??

I also tried jumpering pins 3 and 4 of logic board and disco'd LVDS cable and still no screen glow or pic.

[kevinm34232]

Re: Insignia NS-P501Q-10A Plasma

Anyone?

[tom66]

Re: Insignia NS-P501Q-10A Plasma

The drop in Vs/Va is caused by the control board detecting a fault.

Faults can be with the sustain boards, the buffer board, the panel or potentially with the control board itself.

You need an oscilloscope to check the sustain & buffer waveforms are OK, as one of the boards could be bad.

Also check the panel carefully for cracks especially around the edges very carefully.

[kevinm34232]

Re: Insignia NS-P501Q-10A Plasma

OK, I thought you had said a bad buffer could not cause the voltage drop out. I found a fairly inexpensive Y-Main so I ordered that. The voltages stay up with the y-main isolated so I figured it's either the ymain or buffer right?

[Shinju]

Re: Insignia NS-P501Q-10A Plasma

I have this exact panel downstairs it works but has a 1" veritcal line and 2 horizontal lines neither can be fixed. This series of samsung panels have high screen failure rate.

That said I do have a ton of spare parts, Z and Ysus, logic board, main board and power supply.

The panal boots up fine, plays and all inputs work but the screen is shot.