hantarex mtc 9000 vertical hold problem

[boozy]

I am currently converting a Final Fight cab with a MTC 9000 monitor / J-pac / arcadeVGA. The game worked perfectly before I added my hardware. I have installed the drivers, and tried various resolutions, but the screen continues to roll vertically.  I have tried all the jumper freq settings on the arcadevga card as well, but currently on 15khz. I have arcade maximus installed.
I have tried adjusting the v freq knob, but it its super sensitive and just nudging it causes it to roll, and eventually it gradually starts to slide again.

Would installing a smaller pot along side the current one allow me to more finely tune the freq and solve my problem?  I am out of ideas.   

I cant see why this would be an old hardware problem as the monitor worked fine with the old game hardware installed.

Just in case:  I am using a vga cable from arcadevga to jpac, then to the built in adaptor.

HELP!

Thanks,
Dave

[grantspain]

have you tried linking the v sync and h sync?

[boozy]

Thanks for the reply.  No I have not tried that.  I will give that a go tonight.  Any other ideas what the prob could be?

[grantspain]

you already answered your question-its something to do witht he new hardware
either you need to link the vert sync or your wiring is wrong

[boozy]

Well I took a look at it and maybe I am not completely understanding the linking, but on the monitor board input there is only one wire going to the H sync and nothing going into the v sync.  So does that mean that linking will not help me?  How do I do that? 
I retested the orig game board and it started right up, had to make a couple adjustments, but it locked into place with no rolling.
It cant be the wiring because the only connection that is different is jpac.
Thanks for your help. 

[grantspain]

just to see if it fixes the problem try putting a wire link from h sync to v sync on the monitor signal plug-you could strip back some normal wire and just insert into each pin

[boozy]

Yeah I tried that that did not work. 
I now believe it has something to do with jpac, because I noticed that the sync lights are not illuminating on jpac board.  I guess I did not think about that because I am also using arcadeVGA which should work well with JPac.  The jumpers are set on 15khz and 31khz, and I have the drivers installed for arcadeVGA.  My guess now is that my usb port is not getting power to jpac, so I am going to try a m to m ps/2 switch.

Thanks again!
-Dave