Sega / Mitsubisihi Projection Monitor - Black Screen

[NightWolfx03]

I have a Sega 50P-GHS81 monitor that has a blank screen. It has high voltage and tube glow, but there is nothing on the screen. I already had the chassis out of the unit once and found a bunch of cracked solder joints which sadly did not fix the problem after i repaired them. Does anyone have any experience with this monitor ? I always dread working on the projection ones. I am suspecting something is wrong with the sync signal / sync processing.

Help or schematics would be awesome.

I have included some pictures of the chassis and the issues I found a fixed already.

[lilshawn]

the monitor is made by mitsubishi for sega. info is pretty scarce.

is it dead dead or are you just not geting any deflection? can you turn up the high voltage screen on the flyback(s) and see a horizontal line? these mitsubishi monitors where notorious for the vertical amps frying on them (couple of big huge deals with an "STK" number on it.


maybe give parts or service at http://www.betson.com/ an email and see if they can supply you a manual for it.

[NightWolfx03]

Ok I have 3 big IC's like that in this Chassis, There is a small board labeled DEFL-V with an ic labels STK79315.

There is a diode on this small board i am going to check too that looks like it got hot.

The other IC's are labeled STK 392-040 and there are 2 of those, they appear to be some sort of convergence correction thing.

I wonder too if I could try swapping over the other board form another monitor, though if something else popped this I would pop the other machine too them >_<

[lilshawn]

you'll have to source a service manual of some kind. I have one for another misubishi, not sure if it's similar or not (a huge time crisis deluxe) it has a test procedure for the deflection IC's that should be somewhat transferable. I'll check when i get home

you basically check for a 60 volt output on a particular pin if not, you have to replace them kind of thing.

scrutinize the big resistors around the deflection IC's, they can get hot and go out of whack if the IC's get toasted. they might be those big blue things in your photo. they will have large traces going to the IC's

[NightWolfx03]

Sadly no dice so far on getting it working, might end up replacing it with an LCD panel.

Hmm..

[lilshawn]

what game is this? you may not be able to get an LCD or plasma to work with it.