Replacing a bad cap on TV

[justjoe]

Re: Replacing a bad cap on TV

Ok fixed the new problem, there is a small screw on that tab panel that controls the gamma (i think) and i turned it slightly clockwise when i first discovered it hoping it would fix the screen fade but its actually given me that screen flicker, so ive turned it back to how it was and now im getting a good picture again.

so all fixed then, lesson learned there, just strip it down and rebuild it and hope it works is the answer lol

[justjoe]

Re: Replacing a bad cap on TV

It uses a crappy cheap Chimei Opto (Innolux) panel, they have lots of tab bond problems.

Well since I took those pics of the tabs its been working again, but the pressure on that panel doesn't seem to make any difference to the picture on mine, i cant reproduce the fade out and cant get rid of this flickering, its not usable cos its too distracting even though its very slight.

[tom66]

Re: Replacing a bad cap on TV

It uses a crappy cheap Chimei Opto (Innolux) panel, they have lots of tab bond problems.

[justjoe]

Re: Replacing a bad cap on TV

I'd only put four screws in it (four corners) for now, it may go wrong again and you may need to apply a more permanent shim.

Yea thats what ive done but im going to be playing with it more yet to cure this new dark band problem, the fact i got rid of it shows both problems ive had is down to bad connection/contact. Gonna brainstorm it and see if I can spot a design flaw or something, but im happy to fix the main problem.

[tom66]

Re: Replacing a bad cap on TV

I'd only put four screws in it (four corners) for now, it may go wrong again and you may need to apply a more permanent shim.

[justjoe]

Re: Replacing a bad cap on TV

Well hopefully this is my last post on this, it seems like playing around with the ribbon you spoke about has fixed it, im getting a slight screen flash though, its like when you videotape a computer monitor and on playback you get those dark bands flashing because the frame rates are different, well its like that but very slight, but it only does it when the TV has been screwed back together, so theres clearly some kind of ill fitting part, even though everything is exactly the same, screws all the same torque, no bent plastic or metal anywhere, no trapped wires etc, lcd flats seem to be so temperamental.

I hope this thread might help others because ive learned a lot of important stuff from you guys, thanks for your time and patience.

[justjoe]

Re: Replacing a bad cap on TV

Ok heres the video of it working, not much help i know but proves im not imagining things lol

In the video I turned the brightness and contrast up in the hope it would overload whatever is faulty, just a noob test.

http://www.youtube.com/watch?v=BbLmd...ature=youtu.be

ive been playing a movie via USB drive for past 10 minutes and so far its working ok so far, i guess when i screw it back together it will go faulty again.

[tom66]

Re: Replacing a bad cap on TV

A fault that goes away by itself can just as easily come back by itself; though, it may have been a loose cable, I would be surprised.

[justjoe]

Re: Replacing a bad cap on TV

I would doubt it myself that it is the motherboard, the symptoms do not match up. But that's part of the diagnosis process. The motherboard in your TV is used in about fifty million different TVs. I've seen it in baby 19" and 24" as well. Go by the part numbers written on it, not the model of your TV.

You are not gonna believe this but the TV is now working ok, i turned it on to try to capture more footage of it fading but its working ok, im sure this wont last though.

edit: this is so annoying, it obviously isnt fixed but seems to be working ok.

since it didnt work yesterday i haven't touched it, only pulled the plug out, so it cant be a loose connection.

im going to post a video showing the tv now working, at least then you can see it does work at times.

[justjoe]

Re: Replacing a bad cap on TV

I would doubt it myself that it is the motherboard, the symptoms do not match up. But that's part of the diagnosis process. The motherboard in your TV is used in about fifty million different TVs. I've seen it in baby 19" and 24" as well. Go by the part numbers written on it, not the model of your TV.

of course yea i forgot about that, i heard that somewhere, thanks, i just hope its not the screen.

[tom66]

Re: Replacing a bad cap on TV

I would doubt it myself that it is the motherboard, the symptoms do not match up. But that's part of the diagnosis process. The motherboard in your TV is used in about fifty million different TVs. I've seen it in baby 19" and 24" as well. Go by the part numbers written on it, not the model of your TV.

[justjoe]

Re: Replacing a bad cap on TV

Maybe it's time to get a can of freeze spray. Poundland nearby me have them for a quid for 200ml.
You can spray the freeze spray around the panel and locate the temperature sensitive part.

I'll look into it thanks. Im thinking the problem is somewhere between the cable to th e screen form the mobo or something on the mobo itself, worth replacing the mobo if i find one, i saw a power supply board for only £25 on ebay, but out of interest id love to know what the problem is on the board.

[tom66]

Re: Replacing a bad cap on TV

Maybe it's time to get a can of freeze spray. Poundland nearby me have them for a quid for 200ml.
You can spray the freeze spray around the panel and locate the temperature sensitive part.

[justjoe]

Re: Replacing a bad cap on TV

That is an odd one -- I haven't seen that before. Is there any chance you could get it playing sound then try to show a video.. need to see if the video freezes before it fades or not (if it's freezing it might be a T-con problem.) And the backlight is full brightness all the time through this. Very strange.

I can get sound but no picture, before i get to the channel any kind of picture has come and gone already, unless i unplug it for a week.

Also its not freezing the video, i remember that i was able to scroll the menu while it was fading away.

yes backlight is very bright but you cant see it in the video.

[tom66]

Re: Replacing a bad cap on TV

That is an odd one -- I haven't seen that before. Is there any chance you could get it playing sound then try to show a video.. need to see if the video freezes before it fades or not (if it's freezing it might be a T-con problem.) And the backlight is full brightness all the time through this. Very strange.

[justjoe]

Re: Replacing a bad cap on TV

Heres the video, you dont see much but the word "scart" appears in the bottom left corner.

If I had left it unplugged for another 12 hours or more the picture would have stayed on for a few seconds longer, in fact if i unplug it for 1 week the picture is ok for about 30 seconds then it fades away.

http://www.youtube.com/watch?v=sv-R_...ature=youtu.be


My noob guess is that it seems like something is overheating, or a cap is bad but it will run for a few seconds when very cold.

[justjoe]

Re: Replacing a bad cap on TV

Looks like there's a screw hole there, so there wouldn't be a pad there anyway.

The pads aren't for pressing on the tabs or holding the board in place. They are there simply to reduce the interference that driving the panel produces by completing the shield around the panel.

you're right i see the metal surround has bulges where the pads go now.

ive just managed to get a video recording of the problem, i will update this post with it soon.

[tom66]

Re: Replacing a bad cap on TV

Looks like there's a screw hole there, so there wouldn't be a pad there anyway.

The pads aren't for pressing on the tabs or holding the board in place. They are there simply to reduce the interference that driving the panel produces by completing the shield around the panel.

[justjoe]

Re: Replacing a bad cap on TV

just noticed that this screen panel board seem to be missing some of those spongy pressure pads, the pic shows where 1 is missing, and each end of the board has no pressure pads but has similar gold paint as if they should have some.

These pads have not fallen off and been lost by me, i just know that they are either missing from the factory or its designed this way so i could try making my own pad for it.



I

[justjoe]

Re: Replacing a bad cap on TV

Without seeing a video of the problem that exactly represents what you are getting it's really hard for me to suggest whether it is a panel or main board fault.

ok i will leave it off for a couple of days and see if i can get a picture again, thanks Tom.