Toshiba Regza 32AV615DB Flashing Screen sort of

[aar5384]

Another donated tv that was annoying an elderly friend of mine.

The fault is while she was watching the tv from turning it on the screen appears to dim slightly then brighten again every 2 to 3 seconds. If i look closely at the screen i can see a very faint rolling shadow rolling downwards.

Ive taken a look in the back and cant see anything obviously wrong and wondered if anyone had any thoughts or suggestions?

Another one that might be saved from the council coffers

[aar5384]

Re: Toshiba Regza 32AV615DB Flashing Screen sort of

I moved the tv while it was on and got line paterns on the screen that disapeered quickley, so i tapped the screen and they came again. I disconnected a little circuit board that had a ribbon cable going to the top of the screen and reconnected it and the line patterns dont come on again anymore.

Just a faint rolling pattern similar to what i would get from an old high power supply that gave out noise stuck to top of an old crt monitor, tried to take a picture and video but only shows faintly the dimming and re brightening

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

On the video there is a scrolling upwards but thats just the iphone doing it.

any hints?

[aar5384]

Re: Toshiba Regza 32AV615DB Flashing Screen sort of

I think ive put it down to the logic board, I disconnected the inverter board and got the dark picture where i could very faintly see white items from the menu screen and the image i could see still dipped and got brighter every 3 seconds.

Is there a comon fault on the logic board LC320WXN-SBA1 ?
There is a small ribbon cable that goes to the inverter board from the logic board and the tv works the same when this is disconnected, and ive seen the same logic board on flea-bay without the connector for it, does it serve any real purpose?

[aar5384]

Re: Toshiba Regza 32AV615DB Flashing Screen sort of

Some photos of the internals

[aar5384]

Re: Toshiba Regza 32AV615DB Flashing Screen sort of

Ok Update,

Ive now replaced the tcon board and the dimming and brightening still continues.

The ripple effect ive seen faintly in the background is still there too

What im thinking is could the inverter cause this as the ripple on the screen is more concentrated on the same side of the screen as to where the inverter is, but it could just be my eyes!

The dimming is annoying, it continues to dim slightley and brighten back again every 3 seconds.

I had the tv on for about 6 or 7 hours last night and at some point the dimming and brightening stopped but the faint ripple remained.

Anbody any idea at all?

I have checked all the voltages coming from the power board and all 24v rails are 24.3v all 12 volt rails are 12.1v and all 5 volt are there abouts the same.

[tom66]

Re: Toshiba Regza 32AV615DB Flashing Screen sort of

Checked BL DIM signal from main board to inverter board? What's that doing? It's an analog voltage from 0V to 3V, typically.

[aar5384]

Re: Toshiba Regza 32AV615DB Flashing Screen sort of

Its sticking at around 3.42v

[aar5384]

Re: Toshiba Regza 32AV615DB Flashing Screen sort of

Just noticed the screen going the red etch a scetch spirograph pattern came and went though

[aar5384]

Re: Toshiba Regza 32AV615DB Flashing Screen sort of

Ok the picture has carried on degrading and its going crazy and i suspect this board he sent me to be at fault as it wasnt doing this before. ive filmed it and just uploaded it to youtube

http://youtu.be/YQSAfvOdJkw

[flocko]

Re: Toshiba Regza 32AV615DB Flashing Screen sort of

On the new t.con does the red number match the old one (1905A) this is the part number not the LC320WXN-SBA1 this is the board patten number you need to match red part number and the small ribbon going to the inverter is meant to dim the inverter you can run it without this connected to see if it helps Flocko

[Th3_uN1Qu3]

Re: Toshiba Regza 32AV615DB Flashing Screen sort of

You've got a bad panel. I had the exact same TV with the exact same failure in today.

[aar5384]

Re: Toshiba Regza 32AV615DB Flashing Screen sort of

Floko the t.con 1905A1 matches yes. Everything mataches, ive tried without the inverter ribbon cable to no difference too.

The3_uN1Qu3 Thing is if i reconnect the old t.con the fuzzy erratic distortion stops happening , its only started happening after the new t.con

The issue i need to locate is the dim every 3 seconds and the ripple in back ground that looks like interference

[truep]

Re: Toshiba Regza 32AV615DB Flashing Screen sort of

It could be ripple in the power supply but not likely. If you have a scope, that's the best way to detect it. You can set your multimeter to SC and test as well ( set it for the lowest setting.

[aar5384]

Re: Toshiba Regza 32AV615DB Flashing Screen sort of

Well after the screen mention i decided to take the screen apart and just check all connections and after reassembling the screen now has a few thousand vertical lines in a grey green white sort of colour. I think its now safe to say that i have proberbly buggered the screen up completley

[aar5384]

Re: Toshiba Regza 32AV615DB Flashing Screen sort of

Hang on a sec, something wasnt connected properly, i turned the tv around holding at the top and picture re appeared, ive reinstalled the original t.con and the picture is non fuzzy again but still got the light to dim to light every 3 seconds, oh and tooks like a spec of much got onto the screen inside as i have a black dot up near top right lol.

Looks like ive got to dismantle it all again :/ Sigh

[aar5384]

Re: Toshiba Regza 32AV615DB Flashing Screen sort of

And the faint ripple has gone too !!

[aar5384]

Re: Toshiba Regza 32AV615DB Flashing Screen sort of

Right well, considering ive tested the t.con and the 3 second dim then brighten still happens, ive checked the inverter again by removing it and turning the tv on, with a black screen and the sound still there, ive pressed menu on remote and got a solid white icons from the top of the menu, then with a Led torch pressed against the screen close to the white icon i can see the icon dimming and brightening every 3 seconds still.

So it has to be either the screen or the mainboard right?

[tom66]

Re: Toshiba Regza 32AV615DB Flashing Screen sort of

That footage right there is definitely panel. Who makes the panel?

[aar5384]

Re: Toshiba Regza 32AV615DB Flashing Screen sort of

Well ive got the picture alive again tom66, i took the panel out of its casing and the thin flimsy plastic ribon the goes to a a long strip of circuit board i used the butt of a screwdriver to press them down firmley without moving them, ive uploaded another video now with freeze frame on so you can see the flashing dim and brighten if you watch brads face close.

http://youtu.be/dpDdpozbm2A

Its an LG screen

[tom66]

Re: Toshiba Regza 32AV615DB Flashing Screen sort of

sounds like tab bonds - bane of LG panels as it's -usually- not fixable unfortunately, my luck has been poor with them 0 out of 3 LG panels with tabs fault repaired successfully.