JPAC and MiSTer Highly Saturated Calibration or MiSTer?

Discussion about displays and related hardware including MiSTer filters and video settings.
Escape-To-88
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JPAC and MiSTer Highly Saturated Calibration or MiSTer?

Unread post 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
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larvanoir
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Re: JPAC and MiSTer Highly Saturated Calibration or MiSTer?

Unread post 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.
wodmarach
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Re: JPAC and MiSTer Highly Saturated Calibration or MiSTer?

Unread post 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.
larvanoir
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Re: JPAC and MiSTer Highly Saturated Calibration or MiSTer?

Unread post 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.

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mhartman
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Re: JPAC and MiSTer Highly Saturated Calibration or MiSTer?

Unread post by mhartman »

I use an hdmi to vga converter with my JPAC and it works fine.
dethreign
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Re: JPAC and MiSTer Highly Saturated Calibration or MiSTer?

Unread post 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.
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larvanoir
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Re: JPAC and MiSTer Highly Saturated Calibration or MiSTer?

Unread post 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

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