2 fuses? I believe you might be thinking of B/W DMD controller board.

Check the orientation of the ribbon cables, shown in yellow boxes. If one is swapped around on one end, that will give a blank DMD.

Also make sure you have 5volts to the power connector to the DMD controller board, shown in the orange box. Sometimes wiggling this connector can bring back the screen.

If any of that does not help, test the voltages (-112v, -100, 12v, 5v, 62v) at the DMD power connector.

Guns n Roses (resized).png

Are the insert lamps on the playfield working?

Probably a good time to test the (-112, -100, 12, 5 and 62) voltages on the DMD power cable.

DMD power connector is on the left side in the red box. You can use pins 4 or 5 for your ground meter lead. Remember not to cross the streams (meter leads). Sorry for the GB joke.

1 -112v
2 -100v
6 12v
7 5v
8 62v2019-12-10 13_58_56-DMD not working on GNR _ Data East _ Sega _ Pinside.com - Internet Explorer (resized).pngDMD voltages (resized).png

Right, other way around. I was trying to remember off the top of my head.

So having no 62v is not good. Post a picture of your power supply please.
1 and 2 should only have 12v difference, so currently that is even a problem if the DMD is still connected. Power supply rebuild sounds in order. Also, the capacitors are old as well, so would be good to change them too.

Bally/Williams WPC DMD games.

Power supply needs repair.

This is quite the intense repair. So either have to decide to repair, send it out for repair or buy a replacement power supply. I would recommend the Xpin or another rebuilt original if you go route of another board.

https://www.pinwiki.com/wiki/index.php?title=Data_East/Sega#PS_520-5047-01_-_High_Voltage_Missing_at_the_DMD_display

You could also go with a ColorDMD. Then you would not need to repair this section at all since it will not need these voltages.

That is the way it goes with the old DE power supplies. One day it can work fine and not another.

The fuse related to the high voltage is the 1/2 amp. If it was out, you also would not have any of the 3 high voltages, -112, -100 along with no 62v.

Need to check also if your DMD shorted out as well. Unplug that DMD power connector. With power off on the game, set your multimeter to ohms and check from the ground pin 4 or 5 to pin 8. If it is zero ohms on the DMD, it will also have an issue.

If you test the voltage at the end of the DMD power cable without the DMD plugged in and still have no 62v, yep bad power supply.

I would be surprised if he has the parts on hand. Not often this failure occurs. I even suggest the power supply gets all new capacitors, as they do wear out. Between the high voltage and capacitors , you may be getting close to a cost of new Xpin board.

That is great. Still suggest at the smaller sized capacitors get replaced as they do like to leak.

C2 (100uf 25v), C3 (47uf 63V), and C7 (330uf 25V). These caps tend to leak their corrosive contents on the PCB and kill the 5VDC circuit.