Page 1 of 1
JPAC and MiSTer Highly Saturated Calibration or MiSTer?
Posted: Mon May 03, 2021 6:22 pm
by Escape-To-88
Wasn't sure where to put this. Hooked up my MiSTer to my hori Egret 2 today and worked a treat. However as you can see by the attached picture the reds were extremely high and the whole picture was super bloomy. Now, I calibrated my monitors after they were washed and recapped specifically for GroovyMAME and the picture was amazing. So what I am asking is, is this over bright, red heavy image an issue of the MiSTer's output or is it simply that I have to spend a couple of hours recalibrating again? I suspect I need to recalibrate and haven't yet tried my vert E2 which I calibrated slightly differently but thought I'd ask before I spend an afternoon diving into the back of the machines. Cheers
Re: JPAC and MiSTer Highly Saturated Calibration or MiSTer?
Posted: Sun May 23, 2021 1:18 am
by larvanoir
I have the exact same issue. I'm thinking that this is a result of the video amplifier in the J-PAC, that is meant to boost a PC video signal from 0.7 to 5V. I haven't found a way to disable the on-board amp, maybe there's a way to attenuate the signals between the IO board and J-PAC? Any ideas are welcome.
Re: JPAC and MiSTer Highly Saturated Calibration or MiSTer?
Posted: Sat Jun 26, 2021 2:06 pm
by wodmarach
This and many other problems with the JPAC method is why I've ended up deciding to wait until the mistercade boards become available.
Re: JPAC and MiSTer Highly Saturated Calibration or MiSTer?
Posted: Tue Jul 20, 2021 9:50 pm
by larvanoir
In the end I sorted this out by adding trim pots to the R / G / B lines out of the JPAC to the JAMMA harness. Just a small adjustment brought the image into normal range. I've found this also useful for arcade boards that output video too "hot" for a certain monitor (CPS2 in my case), it's easy to add to an extension harness.
- IMG-6495.jpg (1018.35 KiB) Viewed 2204 times
Re: JPAC and MiSTer Highly Saturated Calibration or MiSTer?
Posted: Tue Jul 20, 2021 9:55 pm
by mhartman
I use an hdmi to vga converter with my JPAC and it works fine.
Re: JPAC and MiSTer Highly Saturated Calibration or MiSTer?
Posted: Thu Oct 13, 2022 10:27 pm
by dethreign
larvanoir wrote: ↑Tue Jul 20, 2021 9:50 pm
In the end I sorted this out by adding trim pots to the R / G / B lines out of the JPAC to the JAMMA harness. Just a small adjustment brought the image into normal range. I've found this also useful for arcade boards that output video too "hot" for a certain monitor (CPS2 in my case), it's easy to add to an extension harness.
Hi everybody, I'm running my MiSTer through Direct Video to a JPAC and running into some issues.
It looks like I'm having the same over-saturation issues you guys are with my JPAC, a couple questions:
What rating trim pots are those? 10k?
Did you take the RGB lines from the chip out of circuit? Cut/Solder traces back to RGB out on JAMMA Connector?
Also, I'm noticing when I plug in my JPAC through the USB, it's like the JPAC loses sync and the picture scrambles, anyone else hear of this?
Pic for reference
Edit: After some poking around with a multimeter, I've come to the conclusion the JPAC is faulty, the voltage on the JAMMA Edge is only reading 0.3 volts across the RGBs lines.
- oversat.jpg (7.15 MiB) Viewed 1249 times
Re: JPAC and MiSTer Highly Saturated Calibration or MiSTer?
Posted: Wed Apr 05, 2023 7:23 pm
by larvanoir
dethreign wrote: ↑Thu Oct 13, 2022 10:27 pm
It looks like I'm having the same over-saturation issues you guys are with my JPAC, a couple questions:
What rating trim pots are those? 10k?
Did you take the RGB lines from the chip out of circuit? Cut/Solder traces back to RGB out on JAMMA Connector?
It's been a while, sorry for the late post. Maybe this is good for somebody's situation, I made these little adapters to adjust the video signal some time ago and they've been very helpful.
It's just a breakout JAMMA pcb with three 1K Ohm pots for the R,G,B lines. I also added voltmeters to 5V / 12V for extra convenience. They work great in my candy cabs which have a JAMMA switcher for multiple systems. If you're switching between, say, NeoGeo, CPS-2 and MiSTerCade, you'll notice that each has different contrast levels. With this I can adjust for each board at the JAMMA connector and don't need to fiddle with the CRT levels. PCB and edge connector are from arcaniac.com
- IMG-7605.jpg (345.41 KiB) Viewed 371 times