On GNR the 12V and 5V are driven from the same bridge so I can see how dips on the 12V supply might cause problems with logic and resets.

Not sure I understand why you would see resets on the Getaway where 5V and 12V are generated from different bridges.

The ColorDMD pulls around 0.75A on the 12V supply but actual current depend on the backlight brightness. I don't have any info on the Pinsound board but when I spoke to them at TPF in 2015 my impression was they were using s different supply than the ColorDMD (at least for WMS games).

The Kahr board uses the 12V supply and a switching regulator to generate 5V for the MPU. This is creating a similar circuit to what's done on the DE power driver board and would explain why you're seeing similar logic problems. Without the Kahr board, the 12V and 5V supplies should be (mostly) decoupled and you shouldn't have issues with the ColorDMD or Pinsound board producing resets.

I don't know enough about the Pinsound board to know why it's creating rapid dips on the 12V supply but you might want to consider replacing the hold capacitor for the unregulated 12V supply to see if there's any improvement in behavior. I've also seen notes on Pinside that some DE power driver boards are more robust to these issues than others.

And some DE power supply boards have reversed the regulated and unregulated circuits. Rottendog boards supposedly have a jumper for this but in ever found it on my rottendog boards and wrote up how to fix the problem.

I had the same problem with my JP. Plus a ton of custom mods installed. Added a external power supply to run almost all the mods and it works fine now.

So the getaway is now working fine? I'm thinking about upgrading my getaway with colordmd and pinsound board. Are you happy with pinsound? And did you make a custom sounds for the game?