Another 60PV250 pic fault but different this time. Help greatly appreciated

[jwarnes]

Had this one a while now. Great tv. Had usual bad inductor solder joints on Z board repaired with new fets and caps etc. Ran perfectly fine for another year! Then this new picture problem emerged. Checked all voltages and usual problems all good yet pic is still trash.
Have a look at the photos.
I cant figure out the reason for the black splotchy patches.
It would be ok then appear when the tv warmed up.
I have not mucked about with the Y board or buffers too much because the voltages all seem ok and the picture is mostly there.
Does anyone have any clues what's going on?
Cheers.

[mmartell]

Re: Another 60PV250 pic fault but different this time. Help greatly appreciated

Not that I think it's the mainboard but run the test patterns.

[jwarnes]

Re: Another 60PV250 pic fault but different this time. Help greatly appreciated

How do you put this one into test pattern?
I cant see the 4 pins?
Photo attached

[ReeceyBurger123]

Re: Another 60PV250 pic fault but different this time. Help greatly appreciated

Looks like Zsus issue to me, whats Zbias at ?

[jwarnes]

Re: Another 60PV250 pic fault but different this time. Help greatly appreciated

Thank you. Reevey can i just confirm with you first the correct way to measure the zbias?

[jwarnes]

Re: Another 60PV250 pic fault but different this time. Help greatly appreciated

I will retest all the voltages and put them up.
Vs 203.1v
Va 55.1v
Vzb 110.3v
Vy -179.9v
VSC 149.5v
M5V 5.15V
And if i change vzb up to 115 or down to 105 picture does not change.

[ReeceyBurger123]

Re: Another 60PV250 pic fault but different this time. Help greatly appreciated

Hmm so it seems the Sus voltages are fine theres a chance the ERC could be low but unlikely as normally if that area fails you would get no image, try running the test patterns as MM said this is done by bridging the Auto exgen pads on the controller and removing the Lvds cable.

[jwarnes]

Re: Another 60PV250 pic fault but different this time. Help greatly appreciated

So I've played with the TV picture settings in the menu and found it is greatly improved if i turn up the contrast to maximum.
Ive repaired the zbias before and its running in spec which is why i don't think it is a z bias problem this time.

[jwarnes]

Re: Another 60PV250 pic fault but different this time. Help greatly appreciated

Is this the area i need to pay attention to?

[jwarnes]

Re: Another 60PV250 pic fault but different this time. Help greatly appreciated

Theres a pot on the Y board that says (SET-UP)
What is that for?

[ReeceyBurger123]

Re: Another 60PV250 pic fault but different this time. Help greatly appreciated

Bridge the copper pads between R51 & R52 with Lvds removed to get test patterns.

[jwarnes]

Re: Another 60PV250 pic fault but different this time. Help greatly appreciated

Test pattern images attatched

[tvtimmy]

Re: Another 60PV250 pic fault but different this time. Help greatly appreciated

That's got to be a zsus problem.
Smarter people than me to reply soon.......

[jwarnes]

Re: Another 60PV250 pic fault but different this time. Help greatly appreciated

Ive noticed the image is not good in normal mode viewing tv. Then if I go through the menu its still no good....untill that is when I get to the image wizard adjustment section where it goes to change the contrast. Two pics attatched. First one before and second pic after it suddenly switches to a vastly improved but not perfect picture.
Then upon exiting the picture wizard it goes back to extrememly poor picture and heaps of ghosting.
And I watched the vzb voltage through this. It didnt change.

[jwarnes]

Re: Another 60PV250 pic fault but different this time. Help greatly appreciated

If it has to be a zbias fault then what could it be if the dc voltage is correct? A timing issue? Is the zbias voltage a smooth dc voltage or should it be pulsing?

[mmartell]

Re: Another 60PV250 pic fault but different this time. Help greatly appreciated

How many ribbons go to the panel from the zsus ? Are they clean and making good contact ?

[jwarnes]

Re: Another 60PV250 pic fault but different this time. Help greatly appreciated

1 cable and yes i removed it and cleaned it today.
What about one of the driver chips on the back of the z sus board that drive the fets. Could a blown driver chip make it do this problem?

[dick_barton]

Re: Another 60PV250 pic fault but different this time. Help greatly appreciated

What voltage would normally increase when you set the brightness from Standard to High since that may give you a clue as to where the problem is.

[jwarnes]

Re: Another 60PV250 pic fault but different this time. Help greatly appreciated

This is my thought also. Today I will test all the voltages and see if any of them change during the menu testing.

[jwarnes]

Re: Another 60PV250 pic fault but different this time. Help greatly appreciated

Well i did that test today. None of the voltages change when i change the brightness and contrast.
So im stumped. Anyone???