Let me state that this is an electrical trainwreck right off the bat; Parts have been thrown at this pin by other parties and to add to the fire prior owners did some interesting wiring hacks. Fuses? We don't need no stinking fuses! Nor line filters either apparently.
What we have is a Lethal Weapon 3 with a DMD that is non-functional. It has a new Rottendog playfield power board, new power supply board and a new DMD004 controller board. It has a Babcock DMD that I'm told was tested fine in a Williams Star Trek next gen but for the sake of troubleshooting will just mark the condition unknown till proven otherwise. The controller board has a display rom from KS arcade marked LW3 Rom 0. The ribbon cable has been changed with no effect.
Symptoms; If the DMD displays anything at all it will do so when it is cold or off for several minutes. The first picture is showing what come up when first booted after sitting all night. Inside a second or two the screen would start to roll like an old tube TV and go black. Otherwise the game plays fine, all control lights work, sound is perfect.
The first thing I did right off the bat was install a new ac line filter and varister to replace the missing pieces and check continuity & polarity of the cord and plug and repaired the missing or disconnected braid grounds to the head. That done I powered up the machine and measured the following.
Rottendog power board test points.
5V = 4.94 volts
12V = 11.62 volts
-12V = 13.6 volts
Power connector at DMD with DMD unplugged
Power connector at DMD controller with DMD004 unplugged
The voltages look decent, certainly within a reasonable range. Where do I go from here? I was thinking of sending the DMD control board back to Rottendog and see if they could test it. I'm also considering swapping some parts with my X-files which in theory has an interchangeable DMD and control board but will hold off for now before I put another pin at risk.
Thank you for your input!