Build Your Own Arcade Controls Forum
Main => Raspberry Pi & Dev Board => Topic started by: ChanceKJ on March 31, 2015, 03:39:46 pm
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Probably a composite -> CGA adapter.
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It's possible to get VGA output from the GPIO pins (documents (https://github.com/fenlogic/vga666) and kit (https://www.pi-supply.com/product/gert-vga-666-hardware-vga-raspberry-pi/)) but I haven't seen anything about CGA output.
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Looking at doing this myself for a cocktail cab. Here's a good page if you haven't already stumbled across it:
http://thearcademan.net/connecting-a-raspberry-pi-to-an-old-15khz-arcade-monitor/ (http://thearcademan.net/connecting-a-raspberry-pi-to-an-old-15khz-arcade-monitor/)
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Well, you could eliminate the completely unnecessary HDMI -> VGA adapter from his setup for one...
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Hmm, I wonder what the lag is like with daisy-chaining these converters.
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Not for this solution, but I do have a 6-player X-men project in mind that could potentially use a Pi.
Still, I'm curious what kind of lag there would be with having an HDMI signal converted to VGA, then converted to CGA. Seems like a lot of video processing to get a Pi running on old arcade monitors.
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Just use the HDMI to VGA converter.
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Just use the HDMI to VGA converter.
Why?
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Rather than start a new topic I thought I would post here since I didn't see a real resolution. There are a couple of other semi-related threads on this subject but here goes anyhow.
I have an RPi 3 B+ model. I have been able to successful run it on a VGA monitor using both a simple HDMI->VGA adapter as well as using the Gert VGA666. However when I try to run at 15khz on an Arcade CRT I get poor results. I do get an image but it is not very bright and seems to have minor "flagging" issues which I would say are sync issues. However, when I connect it to the RGBS connectors of my Sony PVM I get a great picture.
What I've done that has produced a washed out picture with bad black levels
1) HDMI->VGA->VGA breakout cable then combined H and V sync to C sync and connected it to the arcade monitor
2) Gert VGA666 -> VGA breakout cable then combined H and V sync to C sync and connected it to the arcade monitor
I've used the same setup above and then just connected to the PVM RGBS and the picture is good.
Has anyone had good luck just running to an Arcade CRT or is something special, like perhaps a video amp needed to get a good image?
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A video amp might do it. VGA is supposed to put out 0.7 volts max and a think that arcade monitors may be looking for slightly more. What type of arcade monitor are you connecting to?
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A video amp might do it. VGA is supposed to put out 0.7 volts max and a think that arcade monitors may be looking for slightly more. What type of arcade monitor are you connecting to?
I've tried a couple of different ones with similar results. A Wells K4900, Kortek K7000 type monitor, and a K4700.
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This might help.
http://forum.attractmode.org/index.php?topic=777.msg5873#msg5873 (http://forum.attractmode.org/index.php?topic=777.msg5873#msg5873)
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Has anyone had good luck just running to an Arcade CRT or is something special, like perhaps a video amp needed to get a good image?
I have a couple of setups doing this. A retropie setup working, I go HDMI to VGA adaptor and then VGA to SCART with a sync circuit you can get perfect 240p out of the Pi. I used the Arcadeforge UMSA.
The fact it works on the PVM suggests you have a working path.
I then have an arcade setup using a RaspberryJamma board. I know the latest RaspberryJamma board has a video amp but I have the older one without and the picture is still bright enough. Sometimes I have had to give the board a bit more voltage as the 5v that work for a conventional jamma board drops to about 4.7v going to my RaspberryJamma board so maybe a bit more voltage will help. The emulators also have some config values and I seem to recall the config.txt might have had some parameters to do with brightness.
config_hdmi_boost could be worth exploring as it increases the signal over HDMI.
You can read up here half way down;
https://www.raspberrypi.org/documentation/configuration/config-txt.md
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For someone that has this working, could you please post the key elements of your config.txt.
I am trying this with a g07 monitor but can't get a full size picture, nor will it sync properly.
Pi 3 with hdmi_group=1, hdmi_mode=8 for 240p
Hdmi to vga adapter, the typical cheap model on ebay/amazon.
ultimarc j-pac with the 15khz jumper in place
jamma video wires running into the g07.
Other pcbs work with the jamma harness including original pacman pcb, so I know the jamma harness and monitor are wired and working properly.
I am in the US so SCART isn't really an option.
thank you.
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I am trying this with a g07 monitor but can't get a full size picture, nor will it sync properly.
Can you post a picture of the output that you are getting?
Also, do you have overscan turned off in your config?
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I am trying this with a g07 monitor but can't get a full size picture, nor will it sync properly.
Can you post a picture of the output that you are getting?
Also, do you have overscan turned off in your config?
I will post when I get back out to play with it in the garage. (opening day of baseball for kids this weekend....)
I did just buy an "Arpicade" jamma adapter for pi3 that is supposedly all setup for arcade monitor use.
I'll report back when I can test them both.
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Ok so I tried the arpicade with vertical g07. It was touchy but I got it to sync properly and screen size is correct.
It has an hdmi to vga adapter mounted on it very similar look to the cheap one i bought online.
So i took the pi and used my own hdmi to vga adapter into j-pac.
Image is very faint and won't quite sync horiz or vert. But image size is better with the arpicades config.txt settings.
Also the image had more static than arpicade.
So the issue is in the jpac or adapter.
I will just go with arpicade. The quality on it seems good and has built in audio to jamma
Sent from my iPhone using Tapatalk
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Ok so I tried the arpicade with vertical g07. It was touchy but I got it to sync properly and screen size is correct.
It has an hdmi to vga adapter mounted on it very similar look to the cheap one i bought online.
So i took the pi and used my own hdmi to vga adapter into j-pac.
Image is very faint and won't quite sync horiz or vert. But image size is better with the arpicades config.txt settings.
Also the image had more static than arpicade.
So the issue is in the jpac or adapter.
I will just go with arpicade. The quality on it seems good and has built in audio to jamma
Sent from my iPhone using Tapatalk
Interesting because I had the same result without a JPAC. I figured the JPAC would provide enough signal amplification to resolve that problem but sounds like it doesn't. I had this issue on three different Monitors.
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I think i read the jpac has no amp
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I think i read the jpac has no amp
Sent from my iPhone using Tapatalk
Ah. Ok. That makes sense. I started to build an amp but then got bored and gave up.
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Here are the /boot/config.txt settings that allowed the 13inch G07 monitor to work via arpicade.
--the command line to edit this would be> sudo nano /boot/config.txt
--alt-x to say yes to save then exit.
--or you can put the sd card in your pc and edit using a program like notepad++
disable_overscan=1
overscan_scale=1
overscan_left=33
overscan_right=32
hdmi_ignore_edid=0xa5000080
hdmi_force_hotplug=1
hdmi_drive=2
config_hdmi_boost=6
#11 is maximum
hdmi_pixel_encoding=2
hdmi_group=1
hdmi_mode=6
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I think i read the jpac has no amp
Sent from my iPhone using Tapatalk
Ah. Ok. That makes sense. I started to build an amp but then got bored and gave up.
i saw a dee2ree reply on klov that the arpicade does have an amp.
as a test, I set the hdmi boost to 10 and it really sync'd well with no problem or detailed pot adjustments.