Zenith Z50PJ240 Pixel StormHelp

[iaff284]

Hello all! I have a Zenith Z50PJ240 with an LG 50T1 main, Ysus, and Zsus boards. The TV powers on and functions normally but it has a pixel storm with pinkish pixels, pixel blackout in certain areas on occasion, and occasional image ghosting I have downloaded the repair manual and checked the voltages for VS, VY, VSC, and VZB. Everything is within spec. Anybody have any ideas on where to check next? Thanks in advance!

[dick_barton]

Re: Zenith Z50PJ240 Pixel StormHelp

Check for poor or cracked solder joints around the coils on the boards and make good.

[iaff284]

Re: Zenith Z50PJ240 Pixel StormHelp

Thanks for the help Dick, can you give me an idea of which parts are the coils?

[dick_barton]

Re: Zenith Z50PJ240 Pixel StormHelp

This is where photo's, clear and in focus of your boards come in handy.

[iaff284]

Re: Zenith Z50PJ240 Pixel StormHelp

Sorry, here are the pics

[dick_barton]

Re: Zenith Z50PJ240 Pixel StormHelp

The two coils I can see are marked but you meed to check all the solder joint around the boards and make sure they look good.

[Nick's Tvs]

Re: Zenith Z50PJ240 Pixel StormHelp

This is what a typical cracked solder joint would look like on those coils

http://www.nickstvs.com/uploads/5/0/..._i8_w2560.jpeg

As dick Barton stated, there is a chance that you could have an issue with the cracked solder joints, but if you are unable to find any, it is possible you could have one transistor that is not fully but only partially shorted and causing the pixelation and ghosting you are describing. We have seen the pixelation come from the Y-sustain in the past, but the ghosting you have described does make it seem like a Z-sus issue.

[iaff284]

Re: Zenith Z50PJ240 Pixel StormHelp

Ok guys, I checked the coil joints and one joint on each of them may have had a crack so I resoldered those joints. Nick, how do I test the transistors?

[dick_barton]

Re: Zenith Z50PJ240 Pixel StormHelp

If you still have the same pink problem after making good the solder joints then search Youtube for video's on testing mosefts, transistors and diodes. Easier than trying to explain.

[iaff284]

Re: Zenith Z50PJ240 Pixel StormHelp

OK, will do!

[iaff284]

Re: Zenith Z50PJ240 Pixel StormHelp

Well, just put everything back together and no change....looks like its off to a self study program on zener diodes and transisters......

[iaff284]

Re: Zenith Z50PJ240 Pixel StormHelp

Ok, I checked the transistors on the Ysus and Zsus with + to Drain and - to Source and none of them are shorted. Anybody have any other ideas?

[Andrew F. Ali]

Re: Zenith Z50PJ240 Pixel StormHelp

This appears to be a Z-sus Bd issue. Replace the Z-sus Bd and you issue will go away.

[iaff284]

Re: Zenith Z50PJ240 Pixel StormHelp

The Z-sus board has been replaced and the issue is gone!! You guys rock! Thank you all for your help!!!

[iaff284]

Re: Zenith Z50PJ240 Pixel StormHelp

Correction, the image ghosting and pixel blackout is gone however the pixel storm is still present. I verified the VY, VSC, and VSB voltages and all are exactly where they should be. There is a green light on the control board that is blinking in a set pattern. Any idea if it would indicate a fault. Anybody have any other ideas on where to check for the pixel storm problem?

[iaff284]

Re: Zenith Z50PJ240 Pixel StormHelp

So the pixel storm is still present but has moved from the center of the screen with ghosting to the edges of the screen with no ghosting. I am thinking about replacing the Ysus board but dont want to just throw parts at it. Anyone have any advice?

[iaff284]

Re: Zenith Z50PJ240 Pixel StormHelp

Anybody??????