Toshiba 32W3451DB Backlight Problem

[moonshadow1]

Re: Toshiba 32W3451DB Backlight Problem

I have used this guy in the past with no problems
http://www.ebay.co.uk/itm/VESTEL-VES...19.m1438.l2649

Thanks for the information vinceroger69, I bought some and he sent me 22 led's for £9 which included postage and they are exactly what I needed.

[moonshadow1]

Re: Toshiba 32W3451DB Backlight Problem

Thanks vinceroger69 I will check him out.

[vinceroger69]

Re: Toshiba 32W3451DB Backlight Problem

ReecyBurger123

Ok also, you can use 1w pure white smt Led to replace them with.

Do you have any idea where I can buy these from ? RS Components perhaps,or Maplins.

I have used this guy in the past with no problems
http://www.ebay.co.uk/itm/VESTEL-VES...19.m1438.l2649

[moonshadow1]

Re: Toshiba 32W3451DB Backlight Problem

ReecyBurger123

Ok also, you can use 1w pure white smt Led to replace them with.

Do you have any idea where I can buy these from ? RS Components perhaps,or Maplins.

[moonshadow1]

Re: Toshiba 32W3451DB Backlight Problem

Thanks for your reply. D.S.

[dskall]

Re: Toshiba 32W3451DB Backlight Problem

One bad led can cause shut down.

[moonshadow1]

Re: Toshiba 32W3451DB Backlight Problem

Hi I have the same problem with my Toshiba set, it has 2 led's failed on one strip and 1 on the other.
the led's work on either side of the failed ones so am I correct in thinking that they must have failed short circuit in order to let the supply through to the next led in the strip.

Would the power supply board sense that there are 3 led's off and would this be enough to cause the power supply board to "crowbar " itself off and shut down?

I have watched ReecyBurger123 's excellent video and I would like to ask him if he would be willing to sell me two complete working strips ? or would he sell me 3 or 4 led's to repair mine?

Thanks in anticipation of a reply, new member moonshadow1 Northumberland.

[Als_2014]

Re: Toshiba 32W3451DB Backlight Problem

hi i already fixed the tv back light led, having another old strip pulled out from a old tv, as well i did same way as u showed in ur video, it worked fine. thanks
But about the 1w pure white smd led, what about the working voltage?

[ReeceyBurger123]

Re: Toshiba 32W3451DB Backlight Problem

Ok also, you can use 1w pure white smt Led to replace them with.

[Als_2014]

Re: Toshiba 32W3451DB Backlight Problem

Thanks I already watched it nice video, i also have had ur same idea having some strips got from the old tv i fixed before, pulling all strips and modifying the electronic circuit.But i think better if would be possible to find where to buy each single led to replace the burned one..

[ReeceyBurger123]

Re: Toshiba 32W3451DB Backlight Problem

hi, Can i ask u if u have every single led for replacement, thanks

Hello please watch my video, it shows how to test them and replace them:

https://www.badcaps.net/forum/showth...Stacking+video

[Als_2014]

Re: Toshiba 32W3451DB Backlight Problem

Ok I have exact replacements check my pm.

hi, Can i ask where to buy every single led for replacement, thanks

[Als_2014]

Re: Toshiba 32W3451DB Backlight Problem

HI to all friends here, i have same problem with this kind of strip leds, whose The first time i fixed a telefunken 32" tv that use this product of strip, i used to pull off all the strips and changed with the chinese led strip model 5050-1M/60led of a 5meter roll package modifying the electronic circuit, but it takes time and too much work, so please i ask in this forum if anybody knows where to buy each single led .. Thanks.

[BBN]

Re: Toshiba 32W3451DB Backlight Problem

Sorry this has taken so long, but I should be returning this now operational TV to its owner tomorrow.
There have been considerable delays whilst I waited for particular components to be delivered and also a week ago I thought it was OK only for a another LED to fail and cause a new repair + long periods of soaking.

As previously stated I found the initial LED culprit. I replaced this with a 1W cool white LED - which was overbright and whilst trying/testing two more LED's on that same strip gave up working - suspect mechanical failure here after strain put on glued strips when removing. I got these (and other) 1 W leds on Ebay .
Replaced all three leds and all overbright, ended up masking a bit with covers made from polyester drafting film (a bit like tracing paper) and managed to reduce screen brightness further by adding an additional led in parallel, but fastened 'out of site' on backplate chassis of TV. Refixed strips in place with double-sided thermal tape and rebuilt.
This was a bit of a compromise as now several 'bright' spots when certain colours - but I thought acceptable. I ran the rebuilt item for about 12 hours and then another LED (old one) started to flicker and then gave up O/C
Fortunately, as this LED was 2nd in from left hand bottom strip and I had already replaced 1st and 3rd in I had 'available' connections to the 'bad' one and connected a Zener diode in parallel with the second 'bad' led - this was more of a test to check the problem was still leds, rather than a repair - but I then tried things.

I do not know why, but now the two parallel back facing leds involved no longer shine, however even with the now 'missing' 2nd led in left hand bottom corner is only fractionally dim and I still have one 'bright' spot.
I have kept this arrangement, run it for more than 30 hours and it seems a good compromise.

I did find several places where I could purchase replacement LED strips - cheapest being from Romania. However, all of these were effectively 2nd hand, having been removed from 'broken units' . Having seen how much physical force was required to remove these strips I was not very keen on spending a considerable sum of cash on replacements on rather 'unknown' long term quality item. These alone would have cost me at least 10% of a brand new replacement TV.

I will state several things about my experiences here:

The LED's employed might be easy to get and replace IF you could find out exactly what make etc. was fitted.

Many led's you can purchase (like those I got from Ebay) are like beacons in comparison - I did later get hold of what are termed 0.5W rather than 1W ones, but am not keen to try these (as yet).

Taking one of these panels apart is a problematic process and you may well find it necessary to repeat things a number of times (I certainly did - at one point all looked well until in a dark room and white light was seeping out of the surround bottom). It is essential to keep the interior layers free from dust/bits etc; things must all be well aligned and there are a large number of plastic spring tabs involved that must be released/re-engaged that are very likely to snap off without care.
Just taking the back off of this type of TV involves screws and a simple lever action. Getting down to the internal led strips/panel itself requires a lot more screws + plastic clips - a lot more to get right and go wrong + disconnection and manhandling of some sensitive parts too.

Thanks to all of you who have made comments.

[budm]

Re: Toshiba 32W3451DB Backlight Problem

Looks like the same failure as this one, one LED was open, one was shorted.
https://www.badcaps.net/forum/showth...358#post566358

[BBN]

Re: Toshiba 32W3451DB Backlight Problem

Having removed the strips I was able to wok out the connection/tracking using a DVM and two sharp scalpels to penetrate white surface of PCB/strips.

Again using DVM but set to diode test where a voltage reading is expected I was able to test each individual LED - one way round about 0.2V other no reading but very dim pinpoint of light on led connected. One LED @ one end of a strip gave no reading and no light and viewing this more carefully I think you can see a burn mark underneath it! (see attached).

I bypassed this with a 3V9 Zener diode (reverse biased) and then reconnected/repowered everything without rebuild. NOW all backlights come ON (except for bad one of course).

Hence we look to have actually found the problem, even if not cured it yet!

[ReeceyBurger123]

Re: Toshiba 32W3451DB Backlight Problem

Ok I have exact replacements check my pm.

[BBN]

Re: Toshiba 32W3451DB Backlight Problem

These are brief photos of the backlight strips

2 strips each with 11 leds approx. 575mm in length. and 12mm wide

Green PCB joining these is 17DB01.

Each LED strip has written upon it horizontally @ left hand end VESTEL 32 inch REV0.2 TIS-4A 94V-01346
Each LED strip has written upon it vertically @ right hand end LJ AHB2 1003 VES315 WNDL-01.

[ReeceyBurger123]

Re: Toshiba 32W3451DB Backlight Problem

That means that the leds are bad, give me a call if you want the ones I have cheers.

[BBN]

Re: Toshiba 32W3451DB Backlight Problem

As you may expect, looks as Zener diode blown S/C.