Help with Disco DMC-2090DT-2A

Muel

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I finally got an Atari Food Fight that is in really nice condition with the exception of the Disco DMC-2090DT-2A monitor.

It has several issues:

1. The monitor display is dim and not visible under normal lighting. The only way to play the game is in the dark.

2. The monitor has bad pincushion. Narrow at the top, wide at the bottom.

3. The monitor display is wavy.

I'm wondering if just doing a cap kit would be enough to fix these things or are there some other adjustments that I can make?

I didn't see a brightness adjustment, would that be the "SCREEN" adj knob on the inside of the neckboard?

Also, it looks as if someone did a poor solder job on the back of the neckboard, is this supposed to be there? I don't have another Disco to compare it to.

I've never worked on a monitor before but I feel comfortable in discharging the monitor and capping the board. It doesn't look like it has ever been capped.

There is a Red "B" connector floating in the harness - I would assume this is for an alternate monitor??

Where should I start?
 

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I've got the same monitor. My neckboard has the same ceramic cap soldered to the foil side of the neckboard.

I too have an AC ripple that I can't seem to get rid of.

See my thread here:

http://forums.arcade-museum.com/showthread.php?p=1362767#post1362767

Maybe your flyback is failing? Hard problem to diagnose, since replacements aren't available.
 
On more recent monitors, there's usually a pot on the flyback itself labeled "SCREEN" that essentially adjusts the base gain of the whole screen. I got a pretty similar picture to that out of a brand new D9400 that hadn't been adjusted for the tube I put it on yet; cranking up the screen pot did the trick. Playing with your "screen" pot is probably worthwhile, but I'd mark the original position first.
 
Okay, I just cranked up the "Focus" pot off of the flyback - I believe that is what you were referring to. It made very little difference, it is just a bit brighter - not enough to play in a lit room tho. I tried the 'Screen' pot also on the inside of the neck board and it just washed out the screen. So the adjustment knobs helped very little.

I know that there is a bigger problem going on because the monitor is still wavy and has eneven pincushion - about an inch on each side at the top of the monitor. What causes the pincushion?

I would hate to just can this monitor because the tube has zero burn. If it is the flyback that is bad on this chassis, could I just buy a replacement chasis from 8liners and replace my existing chasis with a new one?

Should I try and cap the existing chasis or would it be a complete waste of time?

Any thoughts?
 
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i have the same ceramic cap on my neck board to so i quess it is correct. i wondered about that when i capped my disco.
 
i have the same ceramic cap on my neck board to so i quess it is correct. i wondered about that when i capped my disco.

Did capping your chassis help clean up your Disco monitor? I'm beginning to realize from reading the forum that they are kinda bottom of the barrel as far as monitors go.
 
Did capping your chassis help clean up your Disco monitor? I'm beginning to realize from reading the forum that they are kinda bottom of the barrel as far as monitors go.

i capped it and it looks great.it is in my pole positon 2. i dont know if its bottom of the barrel it is less common then other monitors but i seem to have good luck with this monitor.
 
Yeah, definitely less common monitor. I asked Ken Layton about it, and he told me he's only ever even SEEN one other Disco, and he just scrapped it and put a Wei Ya chassis in.
 
Recap it, including the main filter cap. Visually inspect all solder joints and reflow as needed. Have someone near you rejuve the tube and I'm sure you won't have anymore issues with it. I've done a few Discos and they can be weird at times but the pic can be pretty good after they're rebuilt and adjusted properly.
 
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