Installed a new Vishay DMD in Whodunnit...it doesn't work. WTF???

shardian

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Installed a new Vishay DMD in Whodunnit...it doesn't work. WTF???

I took the good DMD out of my Whodunnit (Dale), and put it in a Lethal Weapon I sold. I then ordered a brand new Vishay from Pinballlife for the Whodunnit. I installed it yesterday and fired her up - completely no life. Kind of hard to mess it up since there are only two connectors - power and signal. Anyone have any ideas. The DMD has no life at all. It worked perfect with the other DMD.
 
I have a spare gassed DMD for testing I will pop in tomorrow just to be 100% sure. Then I'll write Pinballife and tell them the crappy news...
 
I may need a display for my fishtales I'm working on, it works fine but it takes 5-10 seconds to turn on when the pin is first turned on...

On a more positive note I put a pinscore display in my Swords of Fury and it works friggin great now.

Good luck on the fix, Terry's good shit, he'll get you sorted out either way..
 
I have a spare gassed DMD for testing I will pop in tomorrow just to be 100% sure. Then I'll write Pinballife and tell them the crappy news...

Shar I've had many dealings with Terry-I'm sure it will be replaced with no questions asked....
 
I had someone put in a new DMD that also didn't work and called to have another shipped. Then while waiting for the new one, he noticed a cold solder joint on the new one. Fixed it and the display worked, so he sent the other one back...
 
Terry says he has sold over 3000 dmd's and never had a 100% dead one. Asked me to verify my connectors weren't on backwards. I wouldn't have written him if I hadn't! You can't even put the connectors on backwards on that pin, but of course I checked the pinout anyways. I had both DMD's side by side and just swapped the plugs in between cycling the power a few times. It is definitely dead. I'll check for cold solder on the power connector, though I don't see how/why a brand new display would have cold solder.
 
Verified just now with my tester dmd-the new display is doa.

Do you have another game to test the new one in? I have found that DMDs can be very finnicky on different games. On that era WPC game, If the high voltage section isn't perfect on the DMD driver board, certain brands would function, certain ones wouldn't.... You certainly could have a DOA, but I would be a little surprised....
 
Do you have another game to test the new one in? I have found that DMDs can be very finnicky on different games. On that era WPC game, If the high voltage section isn't perfect on the DMD driver board, certain brands would function, certain ones wouldn't.... You certainly could have a DOA, but I would be a little surprised....

I have had three displays in it. The perfect one that was in it - worked fine. I stole it for another game. My tester which works but is gassing, works fine. The Vishay, which does absolutely nothing. That would be wuite a stretch to think the HV section drives two displays perfectly, then does absolutely zilch with a third brand new one.

Anyways, I'm sending it back to Terry.
 
I have had three displays in it. The perfect one that was in it - worked fine. I stole it for another game. My tester which works but is gassing, works fine. The Vishay, which does absolutely nothing. That would be wuite a stretch to think the HV section drives two displays perfectly, then does absolutely zilch with a third brand new one.

Anyways, I'm sending it back to Terry.

Indeed it would be.... but definitely possible.... I had a Whitewater that I bought with a bum display (so I was told).... It was a newer Vishay.... I had a really outgassed Babcock I used as my tester- Worked fine in my Whitewater.... Had a Fishtales next to my Whitewater with a decent Cherry in it... So, I decided to try the Cherry in the Whitewater and the Vishay in the Fishtales..... Both worked (and still work as far as I know) perfectly.

High voltages were just slightly different, but well within spec....

Terry will certainly take care of you, I can't think of a better vendor out there....Good Luck
 
Indeed it would be.... but definitely possible.... I had a Whitewater that I bought with a bum display (so I was told).... It was a newer Vishay.... I had a really outgassed Babcock I used as my tester- Worked fine in my Whitewater.... Had a Fishtales next to my Whitewater with a decent Cherry in it... So, I decided to try the Cherry in the Whitewater and the Vishay in the Fishtales..... Both worked (and still work as far as I know) perfectly.

High voltages were just slightly different, but well within spec....

Terry will certainly take care of you, I can't think of a better vendor out there....Good Luck

...so you're saying Vishay displays are crap then? I can see no other reasoning for completely 'in spec' voltages to cause one display to work perfectly and another to be 100% dead. If that is the case then I should just tell Terry to keep the Vishay and I'll go buy a babcock display for $20 more.

No I don't have another DMD game to test it in. I sold my other DMD game a week ago.
 
...so you're saying Vishay displays are crap then? I can see no other reasoning for completely 'in spec' voltages to cause one display to work perfectly and another to be 100% dead. If that is the case then I should just tell Terry to keep the Vishay and I'll go buy a babcock display for $20 more.

No I don't have another DMD game to test it in. I sold my other DMD game a week ago.

Probably not as much as I am saying the high voltage section on WPC machines is crap :) .... Just posting my experience is all.... Many years ago I had a Cherry display in a LW3 that was problematic that I swapped into a Jurassic Park with a Rottendog PS board and in the two years I had the JP, the display was never problematic (nor was the Babcock that went into the LW3 from the JP)......

I am pretty sure Sterns are shipped with Vishays, and with the exception of a bad run of them in the early LOTRs (I think it was LOTR), they seem to hold up just fine....
 
I'm not an expert on this but when I was looking into a new DMD for my IJ I read somewhere that Vishays draw more 5 volt power than other brands. Maybe your HV section is going? If that's the case than another Vishay probably won't work either.
 
Agreed - I've seen this happen myself when I was doing route work. Shame you can't try that display in another machine. No other collectors you're friendly with in your area?
 
Pin 2 Vishay = -117.7
Pin 2 Dale= -107.6

Pin 7 (Vcm)with vishay = 12.11
Pin 7 with gassed but working Dale: 7.83

Everything else is same

1=-117
6=4.9
8=63.9
 
Interesting:
From the WPC Clay Guide on WPC DMD's:
In regards to the -113, -125 volts (or -103, -115), these two voltages need to be 12 volts apart - that's the important part. That is, if -98 and -110 volts are measured, those two voltages are fine. If -118 volts is measured, the other voltage should be -106 volts. If they are not within 12 volts of each other, the dot matrix controller's high voltage section probably needs to be rebuilt.

Both the -125 and the -113 volts are the same voltage.
The dot matrix display will not work if both the -125 volts and -113 volts (or -115 and -103) measure as the same voltage. These two negative high voltages should be 12 volts apart. The difference in voltage occurs because of diode D6 (D3 on WPC-95), a 12 volt 1N4742 diode. The failure of this diode also kills transistor Q7 (known as Q7 in all WPC generations, a MJE15030). Also check resistor R8 (4.7k ohms 5 watts), if this is bad the two negative voltages will be the same. The -125 volts and -113 volts must be 12 volts apart, or the dot matrix display will not work!

And just for fun since this applies to the gassed Dale Display:
If 12 volts is missing there's either a connector problem, or the dot matrix display itself is "sinking" the 12 volts (disconnect the DMD power connector and see if the 12 volts comes back up, if so the display is bad or maybe the driver board 12 volt section is failing).

The Dale had the 12 volts running at 7!

So apparently NO display is supposed to work when pins 1 and 2 are the same. I wonder why Dale's work when Vishay's don't? Do Dale/Babcock use 12V and Vishay doesn't? That could explain the discrepancy.

Anyways, The Vishay is just fine I would assume. I do have local friends with DMD games, but they are VERY busy and I can't just drop by to do a board swap. I also don't like using friend's fully working games as test beds. If I broke something I would feel really bad.
 
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