Toshiba 42HP66 dim, washed out patchy picture

[WHaThEFLuX]

Going in for my second TV repair attempt, found this set on the side of the road. I'll let the picture and video speak for themselves, I've done a bit of research and it seems that the y sus and z sus boards are likely the culprits.

Haven't torn into the set but I'm assuming the IPMs are bad on one or both boards, I was just curious if anyone could tell which board was bad from the symptoms in the picture/video, and also if it could be something more serious.

It should be noted that any patchy/black part of the screen does fill in with appropriate colors depending on what is shown. Also, the RCA inputs have picture/sound and no HDMI ports are recognized.



http://vid1138.photobucket.com/album...ps3m4zkrlc.mp4

As always any input/advice is greatly appreciated!

[WHaThEFLuX]

Re: Toshiba 42HP66 dim, washed out patchy picture

Apparently the HDMI ports do work, I guess the set didn't like windows 10 resolution settings. So all inputs and sound function correctly.

Anyways, here's a few more pictures showing the washed out image and black patches. When there's no signal there's also lighter grey patches on the right side of the panel that aren't visible when there's something on the screen.

The black patches seem to grow and shrink at will, and the longer I leave the set on the more the black starts creeping into the center of the screen, but as soon as a color intensive scene displays all of the patches fill in except for the ones in the first picture.

[Ltank]

Re: Toshiba 42HP66 dim, washed out patchy picture

Without checking and going by the pictures my 1st thought is the Z board.

[WHaThEFLuX]

Re: Toshiba 42HP66 dim, washed out patchy picture

Thanks Ltank, I'll start with the Z SUS then. I hope you're right, those boards are half the price of the Y SUS boards so I'll most likely just swap it if it turns out to be faulty.

I read that besides checking the boards for shorts, the simplest way to diagnose the IPMs being bad(which apparently is the most common failure on these boards) is to see if they're hot to the touch.

If anyone has a more dependable way for me to test these boards without constructing a jig I'd love to hear it!

[mmartell]

Re: Toshiba 42HP66 dim, washed out patchy picture

That'll work. You can also check the fuse as a blown fuse is a pretty good indication something has gone horribly wrong.

[WHaThEFLuX]

Re: Toshiba 42HP66 dim, washed out patchy picture

Opened her up this morning and found a blown fuse on the Z SUS board, so all clues point to a bad IPM. By the way, I'd like to have a word with whoever decided to keep the back cover in place with 36 screws.

Now I have a decision to make, it seems that the IPM itself is around $50 but I can find the whole board in working condition for less.

I like to get into these projects to gain rework experience but I think replacing the board is the way to go in this situation.

Quick question, I can only find glass fuses locally and the ones on the boards are ceramic, I know the ceramic ones are more durable but does it matter which one I put in? Also, since most of the components on the board(the ones I had access to) are within spec, is there even the slightest possibility that it is just a blown fuse, or does that always mean a more serious failure?

[mmartell]

Re: Toshiba 42HP66 dim, washed out patchy picture

Put a meter on the far side of the fuse holder and other probe to ground. If it beeps then a fuse will do you no good.

Do the same if you purchase a used board as many sold as good are not good.

[mmartell]

Re: Toshiba 42HP66 dim, washed out patchy picture

That sounds too ambiguous. Test BOTH sides of the fuse holder to ground and if either beep you'll need to repair or replace.

[ReeceyBurger123]

Re: Toshiba 42HP66 dim, washed out patchy picture

36 screws ehy try removing 70 from a pioneer set that all have specific places haha. Well done on the diagnoses replace the ipm and fuse and the set should be good guessing its an lg panel ?

[mmartell]

Re: Toshiba 42HP66 dim, washed out patchy picture

Yes these are lg panels. And I have a 60" Pioneer hanging on my wall which seemed to have damn near 100 screws but that was probably just my imagination

[WHaThEFLuX]

Re: Toshiba 42HP66 dim, washed out patchy picture

mmartell, you mean this?

http://vid1138.photobucket.com/album...psx5csgjff.mp4

[mmartell]

Re: Toshiba 42HP66 dim, washed out patchy picture

Yessir. Looks like one is for VA and one is for VS. If you trace that fuse back to the connector above it's likely VS that shorted. IPM failure, repair or replace.

[ReeceyBurger123]

Re: Toshiba 42HP66 dim, washed out patchy picture

Yes these are lg panels. And I have a 60" Pioneer hanging on my wall which seemed to have damn near 100 screws but that was probably just my imagination

Nice haha what Kuro do you have ? I have the 428XD and the one I repaired was a pure vision PDP43ME or something.

[ReeceyBurger123]

Re: Toshiba 42HP66 dim, washed out patchy picture

Ipms are actually repairable depending on how good your soldering is if not just replace it which is probably the best option, be sure to use fresh thermal paste as well if not the new one will overheat and die.

[WHaThEFLuX]

Re: Toshiba 42HP66 dim, washed out patchy picture

I'd love to attempt an IPM repair, can you tell me how it's done? I've just ordered a new Z board seeing as the IPM is $50 and I got the whole board for $30, I wonder if the new board could be bad as well.....it was an ebay special from a tv repair shop confirmed tested and in working order so we'll see.

[ReeceyBurger123]

Re: Toshiba 42HP66 dim, washed out patchy picture

An IPM is built up of mainly SMD transistor ics which work together like normal to-22 size and bigger IGBT to make the voltage, basically its all the transistors and devices built into a chip, saves money but gets very very hot and will fail over time. You can find out what has failed like the Vs Fet chip and replace it, you have to remove lots of solid glue type stuff to access the part and will need very good SMD solder skills. However some IPMS are sealed modules and cant be repaired economically but if yours has an open top which you can access the parts it might be repairable.

[mmartell]

Re: Toshiba 42HP66 dim, washed out patchy picture

nice haha what kuro do you have ? I have the 428xd and the one i repaired was a pure vision pdp43me or something.

6010fd

[WHaThEFLuX]

Re: Toshiba 42HP66 dim, washed out patchy picture

So I received the Z board yesterday and put it in.

When I powered up the set I was greeted with an excellent image, along with some beautiful mal-discharge. I checked all voltages and everything was within spec. I even played around with the Va and Vs to try to clear it up with no success. After doing some research it's apparent that this is extremely common with these sets and the remedy is to reflash the firmware on the control board which is impossible for the average DIYer.

It seems that Capkid is able to perform this reflash and has had success, but before I ship him my control board I wonder if simply replacing the board would clear it up? I see them all over Ebay for next to nothing, can anyone tell me if this is a possible solution?

The mal-discharge was nowhere to be seen with the faulty Z board, was it just not visible because the image was so grainy and distorted?

Is it also possible that the Y sus board is on it's way out too since it's controlled by the same poorly designed heat sink IPM?

[ReeceyBurger123]

Re: Toshiba 42HP66 dim, washed out patchy picture

Lowwer the Vs and Va also any other voltages on the Ymain by 1v or even slightly less I had that issue with a similar chassis was because of age on the panel.
Here is the link to my thread see if it helps.
https://www.badcaps.net/forum/showthread.php?t=47950

[WHaThEFLuX]

Re: Toshiba 42HP66 dim, washed out patchy picture

Lowered the Vs and Va along with the VSC and -VY by 1v and saw no noticeable change. Put the Vs and Va back to spec and played around with the Y board adjustments, now the picture is almost acceptable. It may seem extreme but the VSC and -VY are spec'ed to 120 & 200 and only after lowering both by ~10v was I able to remove about 90% of the mal-discharge. At ~5v lower the reds stopped firing but were replaced by splotches of blue and green.

As it sits now it's watchable and if I didn't know what the issue was I probably wouldn't notice but since I do, it's extremely irritating!

The HDMI input seems to hide it the best, with the RCAs being the worst. I can crank up the brightness and contrast to make it disappear completely but that just leaves me with a washed out image obviously.

I guess I'll consider this set repaired, I wonder how long the y board will last being so far out of spec? I watched a 2 hr movie and it almost seemed to get better the longer the set was on, either that or I was just getting used to it. I began adjusting with the screen set to full white raster as the LG alignment handbook suggested, then got tired and got it to where it is now with a movie playing.

A big thanks to everyone for their help, I'd be throwing all of these projects away if it weren't for the badcaps vets! Now I just have to find some movies that have no black in any of the scenes!


These were the best pictures of the adjusted image, it seems impossible to actually capture the mal-discharge on camera, I guess that means it's not so bad!