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Main => Raspberry Pi & Dev Board => Topic started by: snakerake on November 08, 2017, 11:48:39 am

Title: J-Pac and RetroPie - Compatable?
Post by: snakerake on November 08, 2017, 11:48:39 am
Hey All,

I just picked up a Jamma Arcade cabinet that I'd like to put my Pi in.  I was thinking about getting a J-Pac from Ultimarc to hook it up (with a HDMI to VGA adaptor). Has anyone here used a J-Pac with their Pi?  Are they compatible?
Title: Re: J-Pac and RetroPie - Compatable?
Post by: Spawn2k on November 09, 2017, 01:20:56 am
Its compatible. controls work. audio works but you will prob need an amp. but haven't tested it with an arcade crt. There is a vga to cga on the jpac but you need to configure the pi to output standard res. Since i swapped out the crt for lcd I didn't to any further research but youtube has some videos.
Title: Re: J-Pac and RetroPie - Compatable?
Post by: 1500points on November 09, 2017, 08:54:13 am
Is there a specific reason you want the jamma standard connector the J-pac provides?  Is your setup wired with a jamma harness, or will you be playing jamma pcbs in the machine?

If not you would be fine with the less expensive i-pac.
Title: Re: J-Pac and RetroPie - Compatable?
Post by: snakerake on November 09, 2017, 09:12:32 pm
The cabinet is already wired for Jamma boards. I'm eventually gonna restore it to dedicated cabinet but I'd like to see how the pi does in it in the mean time. So jpac seems like it would be quicket to swap out.
Title: Re: J-Pac and RetroPie - Compatable?
Post by: 1500points on November 09, 2017, 10:45:45 pm
Sounds like the jpac is a wise choice for your scenario


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Title: Re: J-Pac and RetroPie - Compatable?
Post by: snakerake on November 10, 2017, 09:32:47 am
I ordered the J-Pac, will report back with how it goes, I didn;t realize Ultimarc was in the UK though - I guess I'll be waiting a little longer to find out.  I bought an VGA to 15kHz CGA bowrd with additional VGA output awhile back so hopefully it can downscale the video if the jpac doesn't.  I've read up on changing the Pi's output to 240p so hopefully it will work.
Title: Re: J-Pac and RetroPie - Compatable?
Post by: scoltx on November 12, 2017, 09:03:47 am
I ordered the J-Pac, will report back with how it goes, I didn;t realize Ultimarc was in the UK though - I guess I'll be waiting a little longer to find out.  I bought an VGA to 15kHz CGA bowrd with additional VGA output awhile back so hopefully it can downscale the video if the jpac doesn't.  I've read up on changing the Pi's output to 240p so hopefully it will work.

Have a look at the GertVGA666 kit. For native vga out for the Pi.
https://www.pi-supply.com/product/gert-vga-666-hardware-vga-raspberry-pi/ (https://www.pi-supply.com/product/gert-vga-666-hardware-vga-raspberry-pi/)

Because the design is open source you can find them prebuilt on ebay for not a lot money more.  I plan to use this with a PI in one of my Jamma cabs.  Also the jpac has a frequency divider for 31 -> 15kHz out for PC menus etc that can't easily be forced to native arcade res. 

For an audio amp I ordered one of these for Aliexpress
https://www.aliexpress.com/item/Arcade-2-0-Stereo-Audio-Amplifier-Board-Dual-Channel-AUX-Amplifier-Board-Module-DC-1-8/32792986879.html?spm=a2g0s.9042311.0.0.BqFas8 (https://www.aliexpress.com/item/Arcade-2-0-Stereo-Audio-Amplifier-Board-Dual-Channel-AUX-Amplifier-Board-Module-DC-1-8/32792986879.html?spm=a2g0s.9042311.0.0.BqFas8)

Haven't tested the pi/gert/amp/jpac combo yet but in theory all should be good.

I have tweaked a pi2 for A/V port 240p into a crt tv with a trrs composite cable and I must say classic console games look pretty darn good with that combo.
Title: Re: J-Pac and RetroPie - Compatable?
Post by: spocktwin on January 09, 2018, 08:36:36 pm
did you get your jpac going with your pi and the jamma harness.  New to the pi, I did see the articles to reset the video to the crt and I do get screen and it looks good...but that is as far as it goes.  I cannot figure out how to get the controls configured.  I have two joystick and 4 buttons per stick but nothing.  Any advice would be very welcome!
Title: Re: J-Pac and RetroPie - Compatable?
Post by: keilmillerjr on January 11, 2018, 01:20:30 pm
did you get your jpac going with your pi and the jamma harness.  New to the pi, I did see the articles to reset the video to the crt and I do get screen and it looks good...but that is as far as it goes.  I cannot figure out how to get the controls configured.  I have two joystick and 4 buttons per stick but nothing.  Any advice would be very welcome!

See ultimarc website. App to configure default controls is for windows.
Title: Re: J-Pac and RetroPie - Compatable?
Post by: snakerake on February 12, 2018, 02:23:29 pm
No, Unfortunately I don't have it working yet - but I think it's more of a monitor issue, Going to try recapping the monitor chassis then going from there.  I tried another jamma board in the cab and it gave me the same garbage on the screen.

Scoltx, thanks for the tip on the GertVGA666, I'll give that a look.
Title: Re: J-Pac and RetroPie - Compatable?
Post by: mahuti on March 13, 2018, 11:06:19 pm
FYI, I have a j-Pac set up on one of my machines with an old Wells Gardner. Here's the settings

Code: [Select]
###### Arcade Monitor Settings
hdmi_force_hotplug=1 # force out of HDMI rather than composite. HDMI to VGA cable hooked to JPAC
hdmi_ignore_edid=0xa5000080 #enables the ignoring of EDID/display data if your display does not have an accurate EDID
hdmi_pixel_encoding=2 #RGB full (0-255)

hdmi_cvt=320 240 60 1 0 0 0 #custom mode  320x240
hdmi_group=2 #timings typically used by cert monitors
hdmi_mode=87 #use the custom mode set above

config_hdmi_boost=6

## overscan stuff will vary
overscan_left=9
overscan_right=9
overscan_top=5
overscan_bottom=5