Ms. Pacman monitor trouble.

22troy

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I just installed the cap kit I ordered for my Ms. Pacman. The screen looks a little better, but it's still slightly collapsed on the right side. Not too bad, but still noticeable. Is there another issue that it could be? BTW I have a Kortek K1-2-VOA / chasis# KTA-915.

Thanks,
Troy
 
I tried that. It does help, but it's still slightly off. Do you guys think there is a chance that the cap kit I got might have been defective?
 
The new caps matched in uF values. The volts were more though. They said putting in higher volts would make them perform better. Is that true or would the higher volts mess it up?
 
The new caps matched in uF values. The volts were more though. They said putting in higher volts would make them perform better. Is that true or would the higher volts mess it up?

No, that's fine. Do you have a B+ adjustment pot on that chassis? I'm not sure what the B+ should be or where to test it, but if it's off slightly, it could cause that issue....
 
The entire length of the far right section of the image on mine drooped downward, slightly. It took me forever, but I finally got it right with a combination of the 3 pots v-hold v-height and v -posi. Mostly the v-posi and v-height. For a while I was swapping out jamma boards, but stopped doing it, because it was so hard to get that droop out when I had to readjust the pots for each board.
 
I think I found the B+ pot, but it didn't seem to help when adjusting it. Do you guys think it might be a cold solder somewhere on the board? If so what should I look for, and is a cold solder easy to spot?

Thanks,
Troy
 
Do the Korteks have a "Trap" adjustment ?
(I'm asking, I don't mess with Korteks around here)

Could be the yoke got wacked, but don't really want to go there just yet.


BTW - don't blindly adjust that B+, should only be done with a known voltage reference and a multimeter attached.
 
Here are some pics. It's kind of hard to tell.
 

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That's exactly how mine looked, except mine was more pronounced. I had gotten frustrated with it. It became worse every time I switched out a board. I eventually got it to fix itself by adjusting the pots. It required me to adjust 3 pots. It's like a "sweet spot" combination I had to hit, in order to keep it from drooping
 
I've messed with the pots, but this is about the best I can get it. If I go too far one way the right side of the screen will slope upwards and if I go the other way it droops down. It's really frustrating. I have someone looking at the board now. Hopefully they will figure it out.
 
I brought my board to work and had an engineer test the caps that I used to recap it. The majority of the caps did not test well. So now I'm going to try to get some sort of refund (I bought 2 cap kits from the place I bought them), then I have to get some quality caps. What a PITA. I'll repost when I install the new caps. Oh well live and learn.
 
Do you remember where it is on the Bob Roberts website. I can't seem to find it.

Thanks,
Troy
 
It took me a while, but I figured out how to do it on a Sanyo. Read the thread as it's written from a noobs point of view.

http://forums.arcade-museum.com/showthread.php?t=97399

Now I understand that you have a Kortek, but the principle is the same. Find the B+ Pot on the monitor board. It is probably glued into place like my Korteks pot. Now you need to find a small pin nearby, probably labeled "B+ adj" which is where you need to hook your multimeter's positive wire (with an alligator clip) to get a reading. The you need to ground the black wire to the monitor frame. This should give you a reading.

The problem is, that if needs to be adjusted you need to carefully remove the hot glue thats keeping it in place. These plastic pots are often brittle with age, be forewarned so you don't break the pot. I'd recommend removing the PCB for this task. That way it'll be easier to locate that test pin for the B+ adjustment. I couldn't tell you exactly where the pin is, as I've never had to adjust mine.
 
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I brought my board to work and had an engineer test the caps that I used to recap it. The majority of the caps did not test well. So now I'm going to try to get some sort of refund (I bought 2 cap kits from the place I bought them), then I have to get some quality caps. What a PITA. I'll repost when I install the new caps. Oh well live and learn.

What did he use to test them, were they tested in circuit, or out, did he check dielectric, and ESR?

Where did you buy the cap kit?
 
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