Hello guys,

Got a weird issue I thought I'd throw at the wall and see what sticks as searches have net nothing.

Got a nascar with a working but shaky dmd. It was tired I suspect so I swapped in a new one and nothing. Dead. I was careful to make sure all the pins were aligned correctly, and interfaced correctly. I checked the display power supply outputs at the display and found wonky numbers, so I checked at the ps output and again found strange readings, I then checked the incoming AC and found no input for com/white. All the other voltages are correct except for the 18vdc is a volt low. Anyone care to take a stab at it? The game functions correctly except for the dmd.

Boy I'd sure appreciate it.

Right!

Im just not sure what the causal factor could possibly be. How could simply swapping out dmd's possibly cause harm at the transformer level? I'm missing something obvious. Well if anyone has any ideas I'm open to suggestions.

Just an update, a stab in the dark in case anyone happens to read this...

I swapped the display power supply and dmd out of a known working TSPP into the nascar and the old nascar ps and dmd into the tspp. The nascar ps and dmd are fine in TSPP and the tspp stuff does nothing in Nascar. What am I missing?

Here are the ps supply readings from the known working ps in the nascar.
CN1:
+5vdc
+17.3vdc
Key
Gnd
White trans GND
+118vac
+95.2vac

CN2:
-114.4vdc
+91.1vdc
Key
Gnd
Gnd
+5vdc
Blue wire 0vdc
+65vdc

All LEDs are lit on the power driver board. There was work done there before evidenced by new transistors at q1 and q2 and soldered jumpers on j11. None of this affects the dmd I do not believe.

Two separate power supplies with the same issue of no power on the blue wire. Seems like bad odds.

Simply put, what could cause the 12vdc to be absent from two different known working power supplies getting the appropriate feeds..

Anyone? Please???

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I ended up replacing the power supply, driver board and dmd. There is a small burned prong on the back of the board on the IC where it wasn't noticeable.

One strange thing however is that since then, the game insists there are two switch failures which both test and function fine. Maybe a reset will clear it up. Hey thanks for the help!