Pentranic Monitor and Act Labs Light Gun

[SteveS]

Hi,

Thanks for your time on reading this.  Any help will be much appreciated!  I think this is the right forum but let me know if it's not.

I have the following setup:

ArcadeVGA (old style with 2 vga outputs)
Arcade Monitor Video Amplifier (h/v sync cut on amp)
Act-Labs PC USB Lightgun
Pentranic Monitor model 1425. ( This monitor can run at 15kHz and 25kHz but I have it set to 15 right now.)

My problem is the lightgun.  Act-labs claims I should not have any problems with this setup but when I plug in the lightgun it distorts the picture so the middle of the screen is very fuzzy and hard to read but clear on the outside edges. The screen also starts slowly rolling, no adjustment stops it.

I tried Duck Hunt and a few other games but nothing responds (lightgun is on in MAME ini). As noted above the H/V sync is cut.

Any thoughts?  I have no problem buying a newer video card/gun or whatever to fix this.

thanks,

Steve S

[ZeroPoint]

Did you connect the gun before the amp (directly to the ArcadeVGA) ?

And what do you mean by h/v cut on amp ?

[SteveS]

Hi,

Yes, I connect the pc to the gun, then the gun to the amp. 

When I first got the gun it displayed the problems I described in the post above.  I contacted Andy at Ultimarc and he said:

"Steve,

I found the problem I think. The gun does not like composite sync. So this
means the H and V syncs coming from the VGA card cannot be connected
together, as they are on the video amp.

There are two ways around this, wither follow the instructions on
http://www.ultimarc.com/vidamp.html to separate the syncs on the amp, or use a
J-PAC which does not connect the syncs together. I have not actually tested
with a J-PAC but will do so tomorrow.

Andy"

So I cut the sync and nothing changed.  (The picture on http://www.ultimarc.com/vidamp.html is not what I cut, it's on the other side and clearly marked.)  The gun works fine on my pc monitor but not the arcade.  Maybe i got a bad gun???

thanks,
Steve