Has anybody seen this chassis?

[vbaumann]

Hallo!
I purchasesed a 50" rear projection big screen from a Arcade machine and want to repair it. One of the three projection tubes is defective and the convergence does not work (the convergence setup takes no effect, so I think the convergence board is defective).
First of all I want to fix the electronics than i want to buy some equivalent projection tubes which probably are in better condition. The model number of this Projection Monitor is 50P-GK51 and it's from Mitsubishi. I have searched on the internet but there is no useful info to find.

The only hope I have is that the chassis, which is used in this Monitor is probably also used in other big screen TVs or Arcade Monitors. I don't think that Mistubishi constructed this chassis only for one type of Arcade Monitors.

So has anybody seen this chassis before? Does anybody have service manuals for any of Mitsubishi's rear projectors.
I attached some pictures of it.

By the way, I'm familiar to rear projection televisions and crt home cinema projectors, so I already have some experience with this machines. I also own the measuring equipement, so i began to analyse the boards and draw the schematics on my own. But there are some nasty multi-layered boards, especially the convergence-board which is very hard to analyse and to "reverse engineer".

I'm gracefull for any information and help.
Thank you very much and sorry for my bad english.
Best regards from europe,
V. Baumann

[Ken Layton]

Try this site:

www.fixyourowntv.com

[grantspain]

the tubes for these are very expensive,about 300 euro's each-the convergence problem it usually down to one or both of the big i/c's on the heat sinc on the left or their voltage supply-you should be able to get all the parts from suzo(holland/belgium/u.k and germany i think)But i think you will find it would be cheaper to buy a brand new rear projector

[vbaumann]

The fact that the tubes are very expensive is the reason why i want to find out if this chassis is used anywhere else for example in one of mitsubishi's consumer rear projection tv sets or any other arcade projection monitor. If so, i can watch out on eBay for such a tv with defective electronics but working tubes.

By the way, the tubes model number is: P16LHV08BMB, -RFA, and -HKA.

[grantspain]

i have not seen this chassis used on video games,sega used mitsubishi until the mid 90's then changed to toshiba-i think you will have problems finding parts on ebay

[D_Zoot]

vbaumann,

If you should happen to come up with any service information on that chassis I would appreciate a copy.   I've got the same chassis (or very very similar) in a Mitsu set in a Virtua Soccer.   Mine has some manner of sync problem and I've had the same problem as you trying to work on it, the boards are very difficult to try and follow circuits on.  I actually haven't spent much time on mine and it's been at the back of the pile for over a year now, but if I there was some service information available I'd like to take a second look at mine.


D

[vbaumann]

That's good!
Is the model number of your monitor the same as mine?

BTW, have you tried to recap the chassis? I found a info somewhere on the internet that the black Rubicon capacitors have bad ESR qualities and our Monitors are almost 10 years old now!

[D_Zoot]

I don't recall the model number of the set and right now and the set is buried on the corner of the shop.  Your chassis looks identical to mine.    What's important is the chassis series or model number anyway.  TV makers usually used the same chassis for multiple models, when servicing TV's you usually have to go by the chassis number not the set model.


That's true about the caps.  Bad caps/ESR issues have been a problem in game monitors, power supplies, TV's, computers..  you name it.  Usually we see game monitors suffer from bad caps due to age and heat, but in recent years  premature cap ESR problems have been occuring in all sorts of electronic equipment due to substandard/poor grade caps that flooded the market several years ago.

In my case I'd rather do some troubleshooting on my chassis instead of shotgunning caps at it.

[grantspain]

d zoot
what the issue with your projector,is it convergence?
all the virtua strikers i have worked on have earlier model mitsubishi with a seperate convergence board mounted to the right,if i can be of any help please let me know( i have many battles with these monitors to get them correct)

[D_Zoot]

Nope, not a convergance issue with mine.  Mine displays nothing but a mostly black screen with strange squiggly lines scattered about.  The lines move when the game is running.

I've never had any manner of monitor that displays like this one, but if I had to hazzard a guess I would say it's something wrong in the sync circuit.  The layout of the chassis makes it really hard to decipher what's involved with the sync circuit, so I really could use a schem.

Honestly I haven't looked into it too far.  About all I did is plug in my test monitor to make sure it wasn't a game board issue and reseat the various boards on the monitor chassis and then put it aside because I haven't had the time to spend on it.     But it would be nice to fix it and get it out of the shop, it takes up too much space!


D

[vbaumann]

grantspain

do you know the service codes for this mitsubishi monitor?
Is it the same as for the consumer tv sets from mitsubishi?

[grantspain]

depends on the model number,a friend of mine had a mitsubishi that needed setting up and i found the codes on the net by typing mitsubishi convergence codes or service codes.
it your convergence setting o.k but not memorizing

[vbaumann]

No, even the static convergence does not work, which can be accessed without the service codes. The alignment cross just doesnt move. I think it is because one or both of the STK-392-040 IC's do not work. These cosist of three power differential amplifiers and are made by Sanyo. I have read that these are not very reliable and always have a short life time. Is that true?

[grantspain]

yeah thats right,i had a toshiba do the same thing and changed both ic's which cured the fault-definitely worth a go