My First Cap Kit

roothorick

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I'm having some image issues on one of our D9204s and I'd like to do a cap kit before trying anything more intrusive... I'd like a little direction here. Do you just replace the electrolytics? All of them? Is there a premade kit I can grab?
 
Yeah, just the electrolytics - they fail with age. You can get kits for particular monitors from many vendors, like Bob Roberts. Or, you can just by the individual capacitors from an electronic parts supplier.

Capping a monitor is not hard, just pay attention to the polarity of the caps. There are a zillion guides out there on how to do it.

-Ian
 
Yeah, I checked four different places, nobody seems to sell a kit for 9200s. I'll spend some time with the schematic and see if I can figure out what is and isn't an electrolytic without pulling the chassis out of the (in active service) game.

I should mention, my problem is a strong red bias -- all three colors are clearly present, but most things have a significant red/pink tinge to it. Stop me if I'm barking up the wrong tree.
 
Do black backgrounds appear black, or do they have a red tinge to them? What about white areas? Are they white, or are they pinkish?

You might just need to adjust the bias/drive for the red gun. There are usually little pots for this, but I've never worked on a monitor as new as a D9200 - is that one of the ones with the on-screen controls?

It *could* be a cap - and if it were, it would be one in the video amplifier circuits. If the problem is really bad - where everything is very red and you have red retrace lines, then it's probably something with the picture tube.

I'm sure someone who has worked on a D9200 can chime in - again, my knowledge is limited to the 80's and early 90's era monitors. I know that some of these newer monitors have microprocessor controls and such - and looking at pictures of the chassis online, that is one massively complicated arcade monitor.

Do some more research and testing before you chuck parts at it. I'm not sure this is old enough to need a full cap kit.

-Ian
 
White is pretty pure. Black is a dark red. If I adjust the brightness the dark-black red pops in and out at a certain level, which made me suspect caps, though it could be a borderline transistor somewhere.

D9200 was WG's first "digital control" series (thus the D). The OSD has options for color gain, but not bias. The only pots I can find on the board are the two flyback pots, but I'm gonna go over the schematic again.
 
You're welcome. You could also try this:

http://forums.arcade-museum.com/showpost.php?p=1407461&postcount=2

Otherwise, look at the neckboard. There are three drive transistors - one for each color. If the one for red is shorting, it will cause a red background that won't go away. If you don't know how to test it, or aren't sure, you can swap it with one of the others (blue or green) to see if the color problem changes to the other color. If so, then replace the transistor....
 
The factory reset helped a little, no red background in particular, but anything dark (e.g. most backgrounds in attract) is still way more red than it should be. Is it still worth swapping around the CDTs, or should I look at video amplification maybe?
 
You picked quite the chassis for your first. I had good luck re-capping my original chassis with Bob's kit... it only has about 15-20 caps if I remember right.

It fixed some of my issues but I still had a wave issue. It bugged me to no end but 99% of my friends didn't even notice it. Of course I figured I'd bust out a full cap kit... somewhere around 65-70 caps.

Yup... I killed my board.

Ah...history.

:)

Anyway... good luck... just make sure you put the caps back in their proper direction... do one at a time... and you're golden.

:)
 
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