OMG ... again NO! The color DMD is NOT powered off regulated 12V, it uses 12V unregulated voltage.
I honestly want to apologies to the OP for so much incorrect information in this thread while you are trying to learn how to fix your machine.
From Color DMD installation manual:
From TOM Manual page 3-27:
From WPC89 schematics:
The entire unregulated +12V circuit from the transformer to the Power board output:
It honestly is that simple, you rectify the incoming AC power to create DC, you filter it remove low frequency noise, and send it on its way. Any circuit boards under the playfield that use this voltage contain another filter cap at the input to clean up any noise induced on the power line along the way.