Is this a symptom of a bad z-sus? Vizio P50HDM

[johnboy1313]

A friend of a friend gave this to me today. All I was told was that there was a "pop and it quit working". I plugged it in, the screen primed and a blurry no signal box appeared. I connected to a signal and the picture is really dark with a blue tint. There are no fuses that I can see on the zsus. The top heat sink is room temp, the bottom one is hot but not too hot to touch. I've never personally seen a bad zsus so I only have pics from the net for reference. Can I test the IPM on this board like I can on the 42" LG ysus?

[tom66]

Re: Is this a symptom of a bad z-sus? Vizio P50HDM

Yes, that's a bad Z-sus.
Can you supply pictures of it?

[johnboy1313]

Re: Is this a symptom of a bad z-sus? Vizio P50HDM

6871QZH044A. From what I read 44B and 44C are also compatible.

[johnboy1313]

Re: Is this a symptom of a bad z-sus? Vizio P50HDM

Top half.

[johnboy1313]

Re: Is this a symptom of a bad z-sus? Vizio P50HDM

Bottom half.

[tom66]

Re: Is this a symptom of a bad z-sus? Vizio P50HDM

Ah! Joy of joys. I've worked on one of these before, with no success (in so far as the Y-sus failed and cooked the buffers too.)

Can I see the Y-sus -- I have a feeling some fuses are on there.

[Vaughn.E]

Re: Is this a symptom of a bad z-sus? Vizio P50HDM

hey tom66 i am new to this website. But i am in need of help with my tv. not sure how to reach you. other than this.

[tom66]

Re: Is this a symptom of a bad z-sus? Vizio P50HDM

hey tom66 i am new to this website. But i am in need of help with my tv. not sure how to reach you. other than this.

The correct way to do it is not to ask me but to ask me AND EVERYONE ELSE. Create a thread.
I am getting annoyed by people PMing me. There are many other very helpful expert users here. My signature says do not PM me so please do not.

[johnboy1313]

Re: Is this a symptom of a bad z-sus? Vizio P50HDM

Both fuses on the ysus (6871QYH039A) measure good. Both heat sinks get warm but not hot like the one on the zsus.

[tom66]

Re: Is this a symptom of a bad z-sus? Vizio P50HDM

Check the 15V picofuse on Z-sus.

[johnboy1313]

Re: Is this a symptom of a bad z-sus? Vizio P50HDM

Any idea where to look for it? Is it on the back?

[johnboy1313]

Re: Is this a symptom of a bad z-sus? Vizio P50HDM

I may have found it under the lower heat sink. It shows to be good.

[tom66]

Re: Is this a symptom of a bad z-sus? Vizio P50HDM

See the resistors marked Vzbias?
What do you measure across these?

[johnboy1313]

Re: Is this a symptom of a bad z-sus? Vizio P50HDM

These? With the meter on 20k, they both show resistance that slowly climbs to 15.5 before slowing down even more but continuing to climb.

[tom66]

Re: Is this a symptom of a bad z-sus? Vizio P50HDM

I meant voltage across them while the set is in operation.

[johnboy1313]

Re: Is this a symptom of a bad z-sus? Vizio P50HDM

95.5V across each one.

[tom66]

Re: Is this a symptom of a bad z-sus? Vizio P50HDM

Good.

So it's probably the IPM.

To figure out which quickly you will need a scope.

If you want to desolder both you can check them for shorts out of circuit. (Sometimes checking in circuit does not work with these dual-IPM boards.)

My guess would be it is the SUS IPM from the symptoms alone. It's the top-most one.

[johnboy1313]

Re: Is this a symptom of a bad z-sus? Vizio P50HDM

In your opinion, would I be better off getting the scope from work to properly verify the fault or just buy a board feeling certain that it's the IPM? If I do confirm the fault, I'm going to buy a board to replace it. I don't have the equipment, or the finesse apparently, to successfully do the IPM swap.

[tom66]

Re: Is this a symptom of a bad z-sus? Vizio P50HDM

I'm pretty sure it's the Z-sus.
But these boards are not cheap at all.

[johnboy1313]

Re: Is this a symptom of a bad z-sus? Vizio P50HDM

The new Z-SUS came in today. The picture looks better, as in reds look red, blues look blue, but black looks gray, and white is very dingy looking. There is no sharpness to the picture. It's like you're watching it through a window screen, or watching an LCD picture on a really sunny day. Adjusting the picture settings doesn't help.

The upper heat sink on the SUS_IPM gets warm, but not as warm as the lower IPM heatsink does.

I went against my better judgement and bought a board from a seller on eBay that has a no returns policy because it was considerably cheaper. Did I gamble and lose or am I looking at a separate issue?