HD TV Repair Issues?

[BRK]

Forgive my ignorance, but where does one turn to for a HDTV no longer under warranty?

Specifically, I have a Mitsubishi WS-68509 circa 2002?  that is starting to develop an intermittant issue with color displacement.  Greens and Reds close to side of screen are shifted with a ghost effect that at times still provides a relatively acceptably viewing image, other times becomes extremely restrictive.  No rhyme or reason to the issue.  Other times it simply snaps back to perfect form.  

I purchased the set at Best Buy years ago and they want to charge $100 for someone to come out to complete diognostics!  

Any suggestions on resolving the issue or, if it is not a simple matter, where to turn for repairs?

[StarvingForHDTV]

I also have an issue with my Pioneer CRT RPTV.  The blue gun occasionally overdrives and then goes back to normal.  I don't know if it is worth trying to repair or not.

[bubbaridesfast]

I have used Community TV for repairs in the past (pre-HD as my HD sets are newer and OK).

Others have also used them, very reasonable and seem very fair. They were in Muskego but I think they have moved. My boss had them make a housecall in Brookfield a year or so ago.

Edit: I did a little Yahoo search and here is the info for them, hope it's current:
Community Electronics
S75W17317 Janesville Rd
Muskego, WI 53150
(262) 679-2909

[klwillis45]

IMHO, you'd be better off throwing the set out than letting BB get near it or your $$$. I'd look around for a local place.

[Matt Heebner]

The problem you are having is a very common problem with Mitsubishi RPTV's. Basically there are hairline cracks in the solder  on certain IC chips on the mainboard. If you sign up to become a member at //www.hometheaterspot.com, they have step by step instructions on how to do this yourself, or you can hire professionals to come and do it for you. Total time for repar is about 1/2 hour. Mine got bad enough that I had to order new IC chips and have them put in. That was costlier.

If you are not the do it yourself type, do the research on the website, call up a few TV repair places, and explain exactly what you want done. They should be able to fix the IC chips on the spot with a solder gun. They even have pictures of which chips need repair  that you can print out.

[waterhead]

I was able to access a post on resoldering or replacing the convergence IC's HERE. It didn't say anything about member access only, it must be because I use Linux!:)

Numerous sets of the 55807 generation are experiencing problems with the convergence ICs as they become 2 to 3 years old. The problem results in a bowed picture with the colors separated from one-another. The problem usually appears when the TV is turned on, and often goes away suddenly as the set warms up. A light tap on the case can also provide a temporary fix. The problem is that the solder joints connecting the convergence ICs to the circuit board fail after repeated temperature cycles. The problem of course can be fixed by replacing the circuit board, but reflowing the solder joints on the ICs usually provides a permanent fix (at least until another 2-3 years passes). In some cases the convergence ICs need to be replaced.

The repair has 2 major phases: Removing the board and resoldering or replacing the ICs. The circuit board is a typical low-cost consumer product: One layer, single-sided, with small, but not minature geometric features. The lead spacing on the convergence ICs is in the one-tenth inch ballpark. The soldering work is not particularly difficult for someone with experience. Removing and replacing the board is the more difficult of the tasks, and is what the rest of this post deals with.

Should you do this job yourself? If you have soldering experience with similar PC boards, the patience to deal with the mechanical disassembly and reassembly, and are willing to risk breaking something and making it worse, then you're a good candidate to give it a try. Small hands are a plus. If you don't have the experience this is not a good learning project. For the first time I estimate it will take 2 hours to R&R the board, and 30 minutes for the soldering. I imagine that could easily be cut in half the second time.

OVERVIEW: The TV main chassis consists of 3 large circuit boards mounted to a plastic frame in the bottom of the cabinet. The convergence ICs are on the center board, attached to the large heat sink in the middle of the board. There are 2 of the ICs, and they have 18 leads each. The board is held to the chassis with 10 screws. 3 of them also hold down the large heat sink, 2 of them hold down the metal cover at the rear of the board near the A/V input panel, and 5 of them just hold down the board.

REMOVE THE CHASSIS AND/OR THE BOARD? The entire chassis can slide out of the back of the cabinet. If the chassis is out of the cabinet, removal of the board is much easier. But it appears that the IC solder connections are accesable without removing the board from the chassis. What makes this an unattractive approach is the huge number of cables and connectors that have to be dealt with to remove the chassis. It is possible to remove the board while leaving the chassis in place, but physical access to some parts of the job is very difficult. What I concluded was the best approach is a combianation of the 2 approaches: slide the chassis out a few inches (leaving most of the connectors intact), then remove the board.

MAJOR PHASES OF THE JOB:
1. Unplug the set.
2. Remove front and back access panels.
3. Slide the chassis out a few inches.
4. Remove the large heat sink.
5. Remove other mounting screws.
6. Remove cable connectors.
7. Remove board.

SLIDING THE CHASSIS OUT

Remove 3 screws at the rear of the set, disengage 2 plastic hooks at the front, and slide it back. You will almost immediately be stopped by streched out wires, and you need to undo cable guides and unplug connectors as necessary along the way. Try to slide it 6-8 inches back without having to undo too much wiring.

REMOVE THE LARGE HEAT SINK

It's tempting to leave this for the last, but it has to come off anyway, and doing it now opens up a lot of space that makes the other jobs easier. From the front remove the 3 screws and the horizontal piece on the front of the heat sink. Then remove the 3 screws that hold the heat sink to the chassis. Note the ground wire under the middle screw. I found it easier to do this from the back, and a mirror can be helpful.

REMOVE OTHER MOUNTING SCREWS

2 on the front edge of the board, 2 on the rear edge, 1 in the middle, and 2 holding the metal cage on the rear of the board near the A/V input panel.

REMOVE CABLE CONNECTORS

Don't worry about mixing up the cable connections as they are all marked. It may be difficult to pop the 5 ribbon cable connectors (if you think there are only 4, look harder under the plastic bracket holding up the A/V input panel). When I tried to pull them by their little plastic ears it looked like the ears were going to break off. I ended up levering them up from the circuit board with a small screwdriver between the connector and the board. There's a small protrusion on the underside of the connector you can catch with the screwdriver. Popping the connector under the plastic bracket can be a challenge!

REMOVE BOARD

The hard part is over now. Release 2 plastic tabs at the front of the board, tilt the front up, pull it forward a bit to disengage the rear edge, and you've got it out.


Installation, of course, is the reverse of removal. Cleaning up the tangled mess of cables at the front of the board can be frustrating, but with a little time it looks as good as new!

It looks like the solder joints are bad and the solder needs to be reheated and re-flowed.

[waterhead]

Here's another post with pictures of how to repair the board:

http://www.hometheaterspot.com/fusionbb/showtopic.php?tid/105109