4-Player machine completed
I've had this gutted Gauntlet cabinet for years. It had been converted to a bowling game. The only thing left in it was the Atari power brick. Not worth the expense (to me, at least) to collect all the parts and put it back original, so I thought I would create a 4-player MAME machine, at least for now.
I had a guy at work patch up the massive roller ball hole and extra button holes in the CP (really unfortunate because the original CPO was in German). Somebody had already put a 25" monitor in before, so it only took a little tweaking to get the WG U5000 to fit properly. The bezel is made from an old 25" Quazar TV cabinet with some trim lumber to fill the gaps. Daughter and I stripped the black paint from the speaker grille area and "coin arrows." The CPO is a new one.
Using Raspberry Pi 3 with Retropie 4.8. Also using a VGA666 hat to connect to modified VGA cable for RBGVH. Config is at the bottom.
It took me a while to figure out the resolutions to get rid of artifacts in the games. There are a lot of tutorials and threads out there that have you set HDMI_timings at 320x240. . .which makes sense, but my Gauntlet game looked awful with missing lines. See last image. That's when I realized Gauntlet is actually 336x240 resolution. When i adjusted my timings it cleared it up (although i had to bump h_active up 246 for some reason).
For other games I had to adjust the resolutions to their actual res in-game with the Retroarch menu and save the overrides per game. Some of the classic Konami 4-players have black bars on the edges because they have lower resolutions than 336x240, but I'd rather have smooth images with the bars than fill the entire screen with poor animation. . .or have to adjust the monitor every time. Games with higher resolutions I just set to 4:3 ratio and live the artifacts.
I think the theme i am using is called retrocrt-240p. It works great for using an arcade machine monitor. You can actually read the text.
# Disable hardware interfaces that conflict with the Gert VGA666
dtparam=spi=off
dtparam=i2c_arm=off
# Enable the DPI overlay for the VGA666
dtoverlay=vga666
enable_dpi_lcd=1
display_default_lcd=1
# Output 240p timings (Example 320x224, 60Hz - typical for arcade games)
dpi_group=2
dpi_mode=87
#this is the timings that worked best for gauntlet
hdmi_timings=336 1 15 30 42 246 1 4 3 15 1 0 0 60 0 6400000 1