Cannot get Ultimarc JPAC to work with GroovyArcade and HD 6540

[Jimbo]

Hi,

I'm attempting to install the latest GroovyArcade 2020.06, trying to get a Philips CM8833-II 15Khz CRT setup with it.

The CRT is attached to my PC's VGA port via an Ultimarc JPAC which is plugged into a jamma supergun.  The supergun outputs to the CRT via an RGB scart cable.

In this case, during the GroovyArcade boot up, I presume during the monitor tests, the JPAC's "sync in" LED is very bright but no light on the "sync ok" LED.  When the sync-in LED is lit, there's the squiggly lines on the screen, like H-sync is out.  When the LED isn't lit, the screen is blank.

I also tried with an LCD monitor attached to the DVI port...

I boot up GroovyArcade via USB drive and after a while the screen on the CRT has the squiggly image which looks like bad/missing sync.  LCD asks me if I saw something so I press ok.  It then seems to do a few more tests (screens go black but no more action on the CRT) then the LCD panel tells me the connected DVI was selected, and it found a monitor that could be an LCD.

I'm guessing that's not right?  It should find the CRT, right, and the test images should be stable not squiggly bad/missing sync?

The jumper on the JPAC - I've tried both 15Khz alone, and both 15Khz and 31Khz jumpers together.  Same results.

Any help appreciated.  I'm assuming this is a sync issue between the VGA out of the HD 6450 and how the JPAC forwards it perhaps?

To confirm, when using this CRT connected to a jamma game PCB via this same supergun, it works perfectly (i.e. swapping out the PC and JPAC for a Jamma PCB, no problems, perfect picture).

Cheers

[Jimbo]

I've spoken to Andy from Ultimarc who has suggested it would mean the software and card is not sending the correct video signal, such as incorrect frequency or the H or V sync pulses too narrow.

I've got 2 of those Radeon cards, and tried both with the same result.

Anyone got any ideas?

Cheers

[buttersoft]

You'll do better posting up on the GroovyMAME subforum, that's where GroovyArcade discussion happens. It's in the matrix of subforums at the top of any page.

There's a thread with a J-pac solution on the front page, actually - http://forum.arcadecontrols.com/index.php/topic,162912.0.html - though i'm not sure it's a solution that will help you.

The Jpac's can be finicky, but the first step is definitely making sure you're getting 15kHz out of your linux install. Got a multimeter? Most DMM's have a frequency counter, so slap that on your signal and see what's coming out of the jpac vs from the computer itself. Can linux generate composite sync for you, or is that what you're using the Jpac for?

But post up on the GM subforum about this. MAke sure to list your hardware, cables, jpac, monitor, and what distro and installs and anything else you've done