Samsung PS42Q96HD image unwatchable

[zerobug3000]

Hello all, trying to help out an elderly family member who's Samsung tv image is not very well at all. The picture is like snow falling over the screen very grainy, there is horizontal lines and vertical lines and ghosting of on screen menus, this is not just one source but on any source input and the same with every thing disconnected and just displaying the on screen menus. Have tested the voltages from power supply, all voltages are correct on test points on board and match that of the sticker on back of plasma screen, VS VA VG etc. Have carried out the logic board self test by jumping the pins 3 and 4 whilst connected on board disconnected. Get the test patterns displayed on the screen when switched back on, test pattern shows same symptoms of lines ghosting and grainy snow effect. Now although all this information I found on this site to check so far has been extremely helpful, I could not really find a answer to the question I have. Am I right in saying that the logic board self test if failed concludes the logic board at fault? And am I right in thinking this board is actually called a TCON board? the part number was LJ41-04780A

[tom66]

Re: Samsung PS42Q96HD image unwatchable

Check the Vsc and Vsch voltages on the Y-main, and the Ve voltage on the X-main.

Vsc = about -200V
Vsch = about +150V
Ve = around 80-120V

[zerobug3000]

Re: Samsung PS42Q96HD image unwatchable

As the tv is at family members house I will have to do this one evening and update once done. If the voltages are correct would that indicate the tcon board at fault? Thanks for the help

[zerobug3000]

Re: Samsung PS42Q96HD image unwatchable

Check the Vsc and Vsch voltages on the Y-main, and the Ve voltage on the X-main.

Vsc = about -200V
Vsch = about +150V
Ve = around 80-120V

Ok so got there tonight to check it. Vsc= -190v which is marked on back of panel. Vsch= -67v yes thats a minus. Ve = 102v matches back of panel again

And also disconnect y buffer board voltages stay the same.

[zerobug3000]

Re: Samsung PS42Q96HD image unwatchable

There seems to be smd fuses. One marked f5005 open circuit on y sus board any idea what this one is protecting.

[comptek]

Re: Samsung PS42Q96HD image unwatchable

i just repaired one of these
it came in with sound no picture replaced the large fets and resistors and diodes as standard on these.... all voltages adjusted and screen was snowy and looked like a tcon fault on an lcd like bad image like fading image retention and blurring
rechecked psu for dry joints all ok
checked y-sus board and found that fuse f5005 was o/c checked all fets all were ok, replaced and all is well up and running

[zerobug3000]

Re: Samsung PS42Q96HD image unwatchable

Mine worked all spot on after replacing y-sus. My tcon was ok I did check old one after but left new one in as it looked better condition. Every board in mine seemed to have white staining on edges like moisture had got in there.