Voxson VLCD40CP good steady picture also blinking ones

[maxvalutech]

Friend got me this set which displays what appears to be a good steady picture but has same images blinking in and out top and bottom and mostly red tinted by the look of it. Tried factory reset in normal menu but no change. Opened it up to find t-con lead goes straight to screen boards. Power board looks OK as does main board. Any suggestion on what and where to check welcome or is this a no go.

[maxvalutech]

Re: Voxson VLCD40CP good steady picture also blinking ones

Having pulled main and gave it a good look over put it back in and checked all voltages which were all ok and also did voltage regulators which again ok but as most likely cause would be tcon board I pulled the screen surrounds far enough apart to expose that long thin board which has two straps bonded to screen. Fiddling with those didn't result in any change to display. Tried prodding and flexing both tcon and maiboard but again no change. Measured a voltage regulator on tcon ZXMP 6A17 and the gate leg (left) was jumping around in voltage all over the place but often around 8v with next to nothing on middle leg and I think 12v on right side leg. When I went to check these again nothing came on screen as somehow I blew fuse on tcon which was passing 12v through OK. Have to try find a fuse now, meanwhile any thoughts appreciated.

[freakaftr8]

Re: Voxson VLCD40CP good steady picture also blinking ones

Damn, another "tcon on panel" design. Check to make sure that regulator didn't short close in OHMS test before replacing that fuse.

That looks like a failed gate driving signal. If you replace the fuse back to the initial symptom, try some heat along the right and left side of the panel..

[maxvalutech]

Re: Voxson VLCD40CP good steady picture also blinking ones

Couldn't find a fuse so swore a bit and bridged it instead. This led to no intro screen picture (or menu etc) but I know backlights are on and steady. However, voltage check now shows only 10.8v going to t-con and that gate still all over the place. Thanks freakaftr8 I downed tools on that one then to have "a drink and a think" plus got sidetracked selling a couple of sets to pay for my faux pas. Will come back fresh tomorrow and give it a whirl again.

[freakaftr8]

Re: Voxson VLCD40CP good steady picture also blinking ones

Lol ok I'll be here. Check voltage with panel disconnected and see if 12v comes back. If so, something happened to a voltage regulator or a PWM circuit on the panel. Try checking all diodes too.