Toshiba 42VL863B screen problem

[Richiiii]

Hi, i have a Toshiba 42VL863B,
on first power up all i could get was backlight and sound.

After inspection i found the right hand strip circuit board attached to the lcd screen had water damage so i disconnected it form the tcon and half the screen came to life.

Firstly, i might be being a bit stupid here but what are the strip circuit board's (right hand one pictured) connected to the lcd called?

Secondly, am i right in thinking that the small chips (pictured) are surface mount capacitors as iv never dealt with these before and im not too sure how to find replacements as they have no markings.

Do i go by size and colour?

Any help would be very much appreciated!!

[newtothis]

Re: Toshiba 42VL863B screen problem

Ok they are the driver boards.

Water damage... Scrap it

[Richiiii]

Re: Toshiba 42VL863B screen problem

Well tea damage to be precise, i thought i might have to scrap it because the contacts are badly corroded and i don't think there is any chance of swopping the whole board.

Just trying to learn about small smd stuff realy!

[newtothis]

Re: Toshiba 42VL863B screen problem

Yeah they are not replaceable, IMO you would be wasting your time and money even attempting to repair it

[mmartell]

Re: Toshiba 42VL863B screen problem

Inspect the ribbon cables where they leave that board to the lcd for corrosion. That is your enemy. Corrosion on the driver board is not any different than on any other board with the exception you can't remove it to service it. Use isopropyl alcohol and a toothbrush to gently remove the corrosion if it's only on the board.

[Richiiii]

Re: Toshiba 42VL863B screen problem

Thanks for the replies all.

I did inspect the ribbon cables with a small microscope and they'r all fine, the only damage is to the four smd's in the picture, the rest of the board is as it should be.

I'll do that with the isopropyl and toothbrush.

I have loads of scrap boards with chips identical in size and colour to those in the pic that i could swap over, just don't know if they are the same as they have no markings or numbers printed on them.

[mmartell]

Re: Toshiba 42VL863B screen problem

Clean it up first then you can retry or check for shorts.

[Richiiii]

Re: Toshiba 42VL863B screen problem

Ok thanks, will do tomorrow.

Also a bit of googling on these small chips!

[Richiiii]

Re: Toshiba 42VL863B screen problem

So, here's a quick update on this tv! after a lot of searching on google i found that the small chips on the picture are capacitors and go by package size.
So i removed all four of them and three tested bad, i cleaned all of the contacts and tested for shorts, all were ok.
I then matched the bad chips with ones from a doner board, put them on and the tv
came back to life and has been working perfectly for a couple of weeks now.
Thanks again for the help!!

[mmartell]

Re: Toshiba 42VL863B screen problem

Way to stick with it. Keep in mind if there is any corrosion beyond what you saw and cleaned this may rear its head again.

[tom66]

Re: Toshiba 42VL863B screen problem

Nice! Generally speaking, the repair of these types of failures/faults is very difficult. You were lucky, the damage is fairly minor. The capacitors may have suffered corrosion damage leading to them reading leaky or internally shorted.

Modern LCD TVs will be particularly vulnerable with their tab bonds at the bottom, but the same goes for any electronic device, if it gets wet, turn it off and let it dry out before using it. Failure to do so will inevitably cause more damage. Most cases of water damage can be resolved by drying out the device. In some cases further cleaning may be warranted. I would say most LCDs could be fixed if power was removed immediately after the spill occurs.

[Richiiii]

Re: Toshiba 42VL863B screen problem

The tabs didn't look too bad after cleaning and removing old solder, the two middle ones were slightly corroded along the bottom edge, mainly the displacement of solder particles made it look quite bad, hopefully this don't rear it's head but i'll keep my old tv just in case but even if it dose i've learned a lot from this one from the components used to the meaning of electrolysis.
Ps i always tell friend now, if they spill anything on an electrical item unplug it, and get it looked at!