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AaronNM1

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Hello,
I have been pulling out my hair over this monitor since i got it a year ago. Since i got it, it has been a basketcase. From colors going super dark to twitching image, to image bowing on the sides, to randomly scrambling. Yesterday I finally decided to cap it, and color came back, and image looks really nice. But now i cannot get the image to the right side of the screen. Also, I still have the constant twitch in the image. I tested the continuity from the monitor frame to the ground, and it appears that i don't have the frame grounded. I added a ground to the frame, and it added what i would describe as interference to the image. Does anyone know where the the ground for the monitor connects? I cant tell you how much it would mean to me to get this monitor fixed. Any ideas to straighten it out would be appreciated.
 

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Monitors in Sega cabs (at least from Astros onwards) are never grounded. That's why the monitor frame rests on plastic washers.

As for image centering, try adjusting the H.H.15 (horizontal hold 15khz) pot on the chassis if the horizontal position pot on the remote isn't moving the image enough. Horizontal hold could also have an effect on the twitch.

ms9_pots.jpg
 
Cool, so i was able to check the h.hold 15 pot, and it is extremely touchy. I tried to clean it out with deoxit, but that didnt seem to improve anything. Could a super touchy pot be a sign that it is bad?
 
Possibly. You would have to meter it.

What happens when you try to adjust it? Does the position of the image change? There should be some movement before the image goes out of sync.
 
There is no room to adjust it, it is either in or out. The smallest adjustment throws it out of focus, which leads me to believe the pot might be bad.
 
The fact that it goes out of sync makes me believe it's working correctly. It's probably game specific how little adjustment throws it out of sync.

The horizontal position pot on the remote is working correctly? I just tried the pot on mine. I get roughly 6 inches of movement when doing a full turn of the pot.

grantspain frequently visits the Arcade-Otaku monitor tech section of the forum. He knows the MS9 inside out. I would suggest you make a post there.
 
Monitors in Sega cabs (at least from Astros onwards) are never grounded. That's why the monitor frame rests on plastic washers.

As for image centering, try adjusting the H.H.15 (horizontal hold 15khz) pot on the chassis if the horizontal position pot on the remote isn't moving the image enough. Horizontal hold could also have an effect on the twitch.

ms9_pots.jpg
All my Astros have come with the MS9 chassis grounded to the metal frame. Do you mean that the metal frame is not in turn grounded to the rest of the cabinet?
 
Cool, so I put in some more work on this monitor, and I haven't made any progress, but i have ruled some things out. I replaced the horizontal and vertical adjustment pots on the remote board, and the H.hold15 and h.hold 24 pots on the chassis. I am not using the monitor in 24hz mode, but if i touched the h.hold 24 pot, the picture would go crazy, so i thought it might be causing some problems. I still have a twitchy image that is about 4 inches from the right side of the screen.
 

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You've made sure that the remote board, its cable, and the horizontal positioning potentiometer are all okay, right?
 
I was starting to suspect that the remote board cable was a bit suspect. When I moved it, it seemed like the image would get more jumpy. Is there anyone who sells replacement cables?
 
They come up for sale every so often... but it's rare. You can also have a hand at making your own if you feel adventurous.
S12B-EHMS-9 Remote Board Header (on remote board)
EHR-12MS-9 Remote Board Ribbon Connector 0.098" (2.50mm)
SEH-001T-P0.6MS-9 Remote Board Connector Pins 0.098" (2.50mm)
 
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