JPAC video quality issue, I think

[Rustler77]

Hi Everyone

My MAME cab has always been very hard to look at, the image is really unstable and has a sort of horizontal gitter to it. I always thought my chassis just needed a service but then I connected an MVS with Metal Slug X and the picture is really stable.
I'm using:
- Win 7
- HD5450
- CRT Emudriver 2.0_beta_15_12.6_W.7.8.10-64
- JPAC into the Astrocity cab.
I've made a comparison video, the focus is a bit dodgy but you can see what I'm talking about. https://drive.google.com/file/d/1arhz3nwz2x3JenxZBZ0DQV25MXm_5Kp4/view?usp=sharing
Would love to know how to fix this if anyone has any ideas.

Cheers, Ben

[piensken1]

Hey,

Did you test other roms?

I have more or less the same issue.
But sunset riders are running perfect en others not.

[Rustler77]

Yep, on all ROMs. I used Metalslug X because it was the only real arcade hardware I had for comparison.
Not sure about Sunset Riders though, I'll check it  tonight.

Sent from my Nokia 6.1 using Tapatalk

[Sledge]

And i assume you've tried adjusting the sync pots etc?

[piensken1]

thats also maybe an option.. with me its only at some games.. some run more then perfect, others just not :p

[Rustler77]

piensken1 - Sunset Riders is no different than the others for me.

Sledge - I haven't adjusted the sync pots, I didn't realize that was some thing that needs to be done when swapping out PCB's. Its a bit of a mission to get to the back of my cab but I'll give it a go.

[keilmillerjr]

I actually found out i was adjusting the pots a lot, and it was a bad remote control board.

[Rustler77]

I have a Nanao MS8-29FSG.  I don't think it has a pot to adjust the sync, if it does I can't find it.

It was suggested to someone on a different forum with a similar sounding problem that the MAME PC needs to be grounded to the JAMMA harness. I'm in Australia so my Astrocity has been fitted with a 240-110V step-down transformer and my MAME PC gets power from the back of the cab before it hits the step-down.

Also, sometimes I get a decent tingle from the JAMMA harness or the ground shields of things connected to it.  I might have a bit of an earth leak or something, not sure if this would have anything to do with my video problem?

[Mike A]

Bad grounding can cause all sorts of weird problems. You should get that sorted out first. Once that is good your problem may be solved, or at least that will be a check off of the list of possible problems.

[Rustler77]

Had my electrician brother and his multimeter around over the weekend. He pointed out that the power supply in my Astrocity wasn't grounded at all and that there was a 75V voltage drift between the mains ground at the back of the cab and the Jamma harness ground. Shouldn't the AC100V in and the DC out to the JAMMA harness have a common ground to stop this voltage drift?

[keilmillerjr]

Had my electrician brother and his multimeter around over the weekend. He pointed out that the power supply in my Astrocity wasn't grounded at all and that there was a 75V voltage drift between the mains ground at the back of the cab and the Jamma harness ground. Shouldn't the AC100V in and the DC out to the JAMMA harness have a common ground to stop this voltage drift?

Low voltage dc can be isolated from ac. I see this *sometimes* with the cnc machines i work on.

[jimmyj1979]

hey mate i think i have the same issue as you

http://forum.arcadecontrols.com/index.php/topic,159278.0.html

Its almost like the JPAC output is too bright or intense and causing blooming or over exposure?

I'm getting used to it now after having two separate cabs with groovyarcade/JPAC's do this. I dont think we should be adjusting monitor pots to accomodate this, i thought it should be something to do with the JPAC.