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Ultimarc J-PAC issues w/15 kHz monitor

Posted: Wed Apr 07, 2021 4:06 am
by lymando
I got a free j-pac with my recent candy cab purchase and decided to set it up with my MiSTer (at least until the MiSTerCade comes out this summer).

That said, I noticed an issue once everything was hooked up. First everything seemed green. I thought it was my monitor but adjusting it didn't solve the problem. I then got a tip to Flip the switch on my IO board (to auto). This helped but then the reds were off.

Well after reading it seems this is an issue others are having while using the j-pac. Curious if anyone has found a fix for this.

Re: Ultimarc J-PAC issues w/15 kHz monitor

Posted: Wed Apr 07, 2021 9:33 am
by Nat
I have seen similar issues with JAMMA type adapters including J-PACs, when using an IO board.

One solution I know which works is remove C6 on the underside of the IO board it's the 100uf on the SOG switch, and just jumper it with a wire.

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Re: Ultimarc J-PAC issues w/15 kHz monitor

Posted: Wed Apr 07, 2021 1:29 pm
by zorrobandito
I have the same combo and everything works ok. I had to adjust a few settings, especially brightness.

For me there was too much pissing about between games for it to be a workable alternative to groovymame but it did work.

Re: Ultimarc J-PAC issues w/15 kHz monitor

Posted: Thu Apr 08, 2021 3:57 am
by shertz
Curious if anyone has tried using direct video with the hdmi to vga adapter?

Re: Ultimarc J-PAC issues w/15 kHz monitor

Posted: Thu Apr 08, 2021 7:20 am
by TwinX
shertz wrote: Thu Apr 08, 2021 3:57 am Curious if anyone has tried using direct video with the hdmi to vga adapter?
Yes i use this, works good for me.