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Black Rose dmd just went dead - help!

C

coastal

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Jun 15, 2018
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Orkney
DMD on my lovely Black Rose just went completely dead, mid-play.
checked the power header (J604) and I have:
opencircuit (ie disconnected from DMD)
J604-1 = -113V, J604-2 = -92V, J604-6=5V, J604-7=12V J604-8=64V
and when connected to DMD I have
J604-1 = -113V, J604-2 = -113V, J604-6=5V, J604-7=12V J604-8=64V

something looks a bit funny about J604-1 and 2..... manual states these should be J604-1 = -125V and J604-2 = -113V

is it likely that the DMD has just suddenly completely died?
where can I go from here? is it possible to get replacement DMD's? and/or driver boards?
are there schematics of the driver board?

rest of the machine appears to be working fine - I get the "normal" single chime on bootup which usually indicates "no errors to report", and the game seems to play just fine. from the sounds I know that I can also enter the utility menu system....
 
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been reading the various guides and looks like the problem I have is that there is no 12V offset between the J604-1 and J604-2 lines when under load.... so I guess that points towards failed regulation on the DMD driver board. Will remove it and check further.

I had been anyway considering a colour DMD modification, how do these work? do I need an operational driver board for this? the blurb I have read so far indicates that they operate fully ELV so presumably come with their own driver?
 
still bewildered.... how does the upgrade DMD, interface to the old pinball system? do you need a reliable DMD driver board to start with, or does it sit on the CPU data bus?
 
Hi, you still need the data from the dmd driver board - so you use the existing small ribbon cable.
The power is obtained from the driver board via a piggyback connector supplied with the colordmd. So if your problem was anything to do with power supplies from the driver board then it won’t affect the colordmd.
Hopefully, your existing dmd is ok!
 
ColorDMD uses 12v from the main driver board via a supplied piggyback cable, or some other regulated 12v source. I have my TAF one hooked up to @myPinballs 's excellent mod board.

It uses the data cable, but that's it. The power circuitry on the HV DMD board is unused.

Would probably be cheaper to get the DMD power board repaired, but might not be considerably cheaper. The original DMD would be worth ~£80 or so as well if you then sold it, further offsetting the cost.
 
simple fix. I shouldnt have been such a snowflake. the power supply arrangement is .... basic!
DMD board, R7 (the bias resistor on the 113V "anode offset" regulating transistor) had gone open circuit.
These resistors clearly run a bit too hot - the board is badly roasted around this high wattage resistor.
I think Ill try a colour DMD anyway. They look fun.
 
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