Page 1 of 1

Topic: JPAC and Monitor Interference

Posted: February 7th, 2019, 12:09 pm
by Lazyace
Just messing around with my Astro City I've newly acquired and appear to be having the same issue with JPACS and GroovyMAME PC as I had on my Dino King conversion.

I've two GroovyMAME PCs - one smaller Linux build and one larger Optiplex, the latter I put together myself and runs great on my PVM. I also have a homemade Pi2Jamma thingy and experience the same issues with this. When using any of my setups on a JPAC with my Astro (MS-8 29") I'm getting minor interference on the monitor. Almost like a slight 'fuzz' effect, which is more visible due to the large screen on the Astro. I've tried the two JPACs I own and the issue persists - and I can't imagine being unlucky enough to have two bad JPACs! Oddly it seems to clear up the longer you play. Bearing in mind that the PC setups all seem fine going VGA to BNC or VGA to SCART to BNC, all issues point to the JPAC portion of the setup. I had the same issues using a JPAC on my Dino King monitor where it would distort the image - although admittedly is markedly less on the Astro monitor. I've tried a triple shielded VGA cable from the Radeon GPU on the PC and the JPAC and still no joy.

I've not rewired the Astro and it's running the original PSU. The marquee bulb is not present and everything else is original. To be honest the distortion is minor, but noticeable compared to a PCB. I'm having Gunblade (Grant) service the monitor, but I suspect this could be JPAC related and wondered if anyone had experienced anything similar? I read about shielding issues, but not entirely sure it applies here. Any help would be great.