CurtPalme.com Home Theater Forum

[unkyjoesa]

For Curt or anyone else who can help.

I have a 2002 Model Misubishi 56' RP TV that is having a problem.

This same problem occured about 3yrs ago when the TV was still under warrnanty.

The red gun all of the sudden has lost its convergence and has shifted up about 6 inches, hope I described this properly.

Last time the tech came out to the house and fixed it right here, I think he said the convergence circuit was out, I know he repaired the board right here in the living room and said it was a common problem on these Mitsubishi's.

Is this some thing I can tackle on my own, or has anyone seen this problem and if so could you direct me to a source where I might be able to correct this myself?

Worst case I will call the same company back out, they are top notch, I just wanted to save myself a little bit of money and perhaps the joy of fixing this myself.

THanks in advance.

[Nashou66]

There is a calibrator by the name of Craig Rounds who is a Mitsu expert.

http://www.cir-engineering.com/

he might be able to point you in the right direction send him an e-mail. Also MrBob on AVS forum is also well Vs'd in Mitsu's but not sure of what level and the RPTV forum on AVS might be able to help you as well if Curt cant.

Athanasios

[unkyjoesa]

Well the wife reminded me that last time the tech was here he told us it was a cold solder joint on the conv IC.

I have pulled the board "dont worry I am handy with a soldering iron" and I see the IC he was speaking of.

Last time we could move or lightly tap the set and it would come back to a perfect picture.

This time, this is not the case, and I am assuming since it was run with cold solder joints for a couple of years it probably stressed the voltages on the IC and it has finally tanked.

I am also getting some help over at hometheaterspot as well as this seems to be a common problem, even though there is no mention of my model

Anyone else care to chime in - specially Curt

Thanks in advance for all the help.

[Nashou66]

Maybe just replace that IC if its not to hard to remove. and see what happens. some times you can get free samples of IC's directly from the manufacturer.

Athanasios

[macgyver655]

Whats the numbers on the IC?

[unkyjoesa]

That number would be STK393-110

After sleeping on it, I am thinking I will do one of two things.

1 - Order a replacement board for the unit from PTS Electronics
2 - Pay someone else to do the board repair.

I was under the assumption that the board was a single layer PCB, but it is in fact a multi layer PCB and these old eyes aint what they used to be.

I guess I could find someone locally who does the board level repairs.

You guys know of anyone in the San Antonio TX area that could assist?

Thanks in advance.

P.S The unit is in great condition other than this issue, and evidently Mits knows of the issue as it is the main culprit for failures in all of thier lines. These IC's generate so much heat they end up loosening the solder joints or making the board around them brittle from heat, then their voltage begins to flux and bam they are out.

Thanks again for the help.

[Nashou66]

Maybe on the new chip or board put an ic cooler on it. I saw some they run off a 12 volt supply line and one side gets cold the other gets warm. I forgot what they are called exactly.

Athansios

[unkyjoesa]

Well I grew a set and after cleaning the board very well with DN Alc I took out my trusty iron and desoldering braid.

It took about 30 minutes but I got that sucker out and didn't damage the board.

I ordered a replacement chip for about $20 and it should be here next week sometime.

I decided not to replace the board as a full setup would have to be done on the set.

I will try this first and see if it fixes it, if not I am only out a few dollars eh?

I am going to find some way to add a 80mm fan to the unit to help this component dissipate heat a little better as well, but I think the poor solder job in the beginning is what is killing this chip, that and the fact that heating and cooling the thing probably made the voltage fluctuate and killed the IC. This seems to be the deal with these chips they last between 2-5 yrs and then bang they go out.

I will update the post with more info when I get the chip installed,.

Thanks for the help.,

[macgyver655]

I believe that number has a different replacement to solve the repeat failure issue. I would have to look thru my notes but if you already ordered one then its to late for that. Also you have to make sure the replacement is an original Sanyo part or it will surely fail again.

[unkyjoesa]

I ordered the Sanyo exact repalcement part off of the MCM website.

But it cant hurt to have the other number and order than one as well just in case, it is still cheaper than having the set worked on.

I also checked all the resistors in the circuit as well per the repair manual and they all check out and all of the caps look fine as well.

MaGyver - thanks for all of your help and send me that part number if you can find it, many thanks!

Wish me luck, I will be posting my results.

[macgyver655]

I checked my notes and the STK393-110 is a valid number and does not have an upgrade yet. Just remember when installing the new chip to use a thin layer of heat shink compound. Then move the chip back and forth on the heatsink until you hear metal scrape. To much heatsink compound is not good and will cause overheating and failure. Good Luck !!!

[unkyjoesa]

Thanks for the quick reply.

I guess I need to order a couple more of these just in case as Sanyo is discontinuing those part numbers.

Is there also a pico fuse in that circuit that should be checked as well?

I am currently going over the schematics as we speak to check.

MCGyver, thanks again for all of your help it is greatly appreciated!

[macgyver655]

With the Stk393-110 chip I'm assuming you have the VZ9 or V21 chassis. I dont remember the circuit specifically but there is usually a pico fuse in the power feed line to the convergence ic. However usually when the fuse is blown the set wont turn on or will shut off after turn on or wont turn back on after shutdown for 15 to 30 minutes. But it wouldnt hurt to check it just to make sure. Even though Sanyo is discontinueing that chip along with about 40 others, they will still be available long after your set is worn out so I wouldn't worry about unavailability.

[unkyjoesa]

Macgyver,

I have the V9 chassis.

Thanks for the info, the set was powering up, just the red conv was wayyyyyy off.

I will check the fuse to be sure before re-installing.

When installing the new IC -17or18 pins do I need to sheild them from heat with some sort of heatsink or just be quick with the iron?

Glad to hear the parts will be avail for a while, this is the second time this set has had this problem. I bought Mits because of thier proven track record, I guess I could also blame Sanyo, but this is obviously a bad design, I see people all over the net having the same problem, and it seems to be affecting a lot of models.

There is also some concern about glycol leaking onto the system boards, I have checked mine and it seems to be okay, but this stuff is death to the boards and they aint cheap. Actually they aint to expensive.

Thanks again for the help.

[Fujifrontier]

Unkyjoe you're close/in SA? Could you teach me how to solder?

[unkyjoesa]

Here is a good place to start.

http://www.aaroncake.net/electronics/solder.htm

I would recommend starting on an old component/pc board that is no longer used.

I prefer de-solder braid to desolder.

[unkyjoesa]

Update:

Replaceded the IC in question, cleaned up the board, did a resolder on all heat stressed components.

Did a complete reconverge and I have my beautiful picture back again.

Oh and the wife is VERY pleased, extra friendly pleased

So anyway, thanks to all of you that lent a hand.

I documented some of the procedure with pictures and they can be found here.

http://www.flickr.com/photos/unkyjoe/sets/72157604009197042/

Again, thanks to all of you that helped.

[Nashou66]

Great news! Doesn't it feel great to fix something on your own and save $$$$$

Athanasios

[macgyver655]

Glad to hear it all worked out for you. Enjoy