Wells Gardner K7000 19-inch monitor, vertical position adjustment question...

[KingDiamond]

I recently acquired an arcade cabinet and I'm converting it into a MAME cabinet. I'm using ArcadeVGA and running everything in Windows XP. Everything works fine except when I run games (using MameWah as the frontend) there is about a 1 centimeter black space across the top of the screen. I can adjust the vertical size and make it big enough to fill in that area, but then I'm losing whatever picture information is supposed to be at the bottom of the screen. Basically if I could move the vertical position up just a bit then everything would be fine. The problem is that the vertical position is already set as far as it will go. I read in the Wells-Gardner manual that the HV Adjustment pot can be used if the vertical hold has been changed (and I have changed it). I looked at the HV Adjustment pot and I don't see any adjustment screw on it or anything like that. It looks like a solid plastic component with three pins going into the circuit board.

Some other info about the monitor, it says it was manufactured in Chicago, Ill in 1993. There is also a service tag on it that says it had been serviced in 2003. Also the entire back of the monitor is covered in a thick soot. I think this machine must have been in a bar with smokers because I used to work as a computer technician and saw the same thing in smoker's computers. Is there any harm in just using a vacuum cleaner and air duster can and just trying to blow the stuff off?

[Ken Layton]

Adjust the 50/60 hz pot in conjunction with vert size, vert position, and vert hold.

The pot location is shown here:

http://jstookey.com/arcade/WG_25k7191/

Cleaning monitors and monitor boards has been well-discussed in the past so I suggest searching.