(Topic ID: 243667)

WPC DMD Driver board taking 60V out


By robm

4 months ago



Topic Stats

  • 8 posts
  • 5 Pinsiders participating
  • Latest reply 7 days ago by Evangelist
  • Topic is favorited by 1 Pinsider

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#1 4 months ago

Have a STTNG that i picked up non working - the DMD did not work, and found the 60V section out on the DMD driver board - so i repaired the HV section, and put another (old with some lines missing) display in the machine and it worked for 10 mins or so, then the display died. Tested the voltages and the 60V was out again (was reading 0)!

So i send the DMD driver away to a tech, and he rebuilt it again (i thought my repairs must have been dodgy), put the newly repaired board in, worked for 10 mins again, then the display was dead - could smell a slight hot smell and the resistor for the 60V section on dmd driver board was really hot.

I am at a bit of a loss - could the display be causing the issue and taking out the 60V section of the DMD driver board? I tested the transformer without it plugged into anything and left it on for 20 mins - the purple pair of wires going to the DMD driver board stayed stable at around 109VAC, and the white pair 87VAC. So i am assuming its not something funny with the transformer putting out too high voltages.

Is there anything else to test or check (voltages, power driver board?) before putting a different display in there - i don't want to keep killing DMD driver boards!!

#2 4 months ago
Quoted from robm:

I am at a bit of a loss - could the display be causing the issue and taking out the 60V section of the DMD driver board?

Yes! old/aging plasma displays draw more current as they age. The absolute best thing you can do is install an LED dispaly; these are fairly inexpensive, likely cheaper than you paid to have your HV section restored, or if you want an awesome color display, the Color DMD LED (not LCD) is the way to go on this game! http://shop.colordmd.com/led-replacement-display-sigma/

EDIT: I almost forgot .... I like to tell everyone that installs an LED or LCD display to either pull the HV fuses from the Display controller, and/or disconnect J605 (HV connector) from the display controller as there is no reason to power the high voltage section of this board any longer.

#3 4 months ago

I would also suggest a cheaper PinballSP color display if you want an alternative.

https://pinside.com/pinball/market/shops/1097-pinballsp

#4 4 months ago

do you have another spare DMD? They can do funny things when aging and starting to short due to failed lines or internally shorted components on the display itself. As its the main load on the dmd driver it is a major suspect.
Especially since you eliminated the input voltage as a cause

#5 4 months ago

Thanks guys. Unfortunately by the time i get a colourdmd shipped to Australia its $650-$700. So its more economical to stick with standard, plus repair - anyway, i did try a new DMD with another repaired DMD driver board and it has run for 40 mins with no problem. So will assume that the old DMD was causing the issue.

4 months later
#6 9 days ago
Quoted from robm:

Thanks guys. Unfortunately by the time i get a colourdmd shipped to Australia its $650-$700. So its more economical to stick with standard, plus repair - anyway, i did try a new DMD with another repaired DMD driver board and it has run for 40 mins with no problem. So will assume that the old DMD was causing the issue.

The shipping & weak Aussie Dollar not fun....

I had issues with the high voltage section on the DMD controller board in my T2 a while back so did my first refurb of a DMD controller so documented it on video as I was a little daunted at first but much easier than expected....

#7 8 days ago

The shipping & weak Aussie Dollar not fun....

Understandable, the fix you are doing should last you for a very long time; thanks for posting a video of this as I'm sure this information will be useful.

I do have one recommendation for anyone revisiting this post to rebuild the HV section, and that is to not remove any the heat sinks, all you have to do is remove the screw and nut fastening the transistors to the heatsinks, then just de-solderer them as you would any other component.

#8 7 days ago

Thanks pin_guy for the suggestion on the heat sinks?

Here is part 2 of the videos...

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