WPC DMD and very high voltage

[Joe_E...@hotmail.com]

Hi
I'm in the process of restoring a Doctor Who and I'm having a problem
with the DMD. It currently displays -- a big improvement over my last
post -- but now when the game is on most of the pixels are on all the
time and it strobes like a police car light on a window. Here is a
picture: http://www.joeentropy.net/WorkingDMD.jpg

I've measured the voltages and it's running a little hot... pins 1, 2,
and 8 are -138V, -126V, and 69V respectively. I've read that people
jack up the voltages on the display driver board to make old displays
brighter, but my display is brand spankin' new. Is that my problem?
Will a display driver board that's more in control of itself solve my
problem? I've been thinking of just buying a new one since they're only
$90.

Thanks,
Joe

Want to read about my attempts to restore a pinball machine? Go to
http://jepinblog.blogspot.com/ and laugh yourself silly.

[Joe_E...@hotmail.com]

Oh, yeah... question number two: Is using my brand spankin' new DMD
with this higher than average board bad for the DMD?

[Lloyd Olson]

Have you checked what your game is wired for ? I'm wondering if your outlet
is 120, and the game is wired for 100 ? LTG :)

<Joe_E...@hotmail.com> wrote in message
news:1153440267.2...@b28g2000cwb.googlegroups.com...

[Joe_E...@hotmail.com]

How can I tell if it's wired for 100?

[Lloyd Olson]

Check Clay's site. I think it's under the Data East stuff, a voltage
conversion section. That would guide you.

Don't just change things, measure your wall outlet voltage and then check
the plug on your game. LTG :)

<Joe_E...@hotmail.com> wrote in message
news:1153447668.8...@b28g2000cwb.googlegroups.com...

[Lloyd Olson]

http://www.marvin3m.com/de/index3.htm#convert Here's the link. LTG :)

"Lloyd Olson" <l...@ssbilliards.com> wrote in message
news:kKednX3jbaAwql3Z...@skypoint.com...

[Joe_E...@hotmail.com]

I never would have looked under the Data East section... according to
the pin configuration chart, I have a red-blooded All-American 115V
plug.

[pindog]

Joe,

Do an Ohm reading (test) of the large resistors on the DMD driver
board.
Namely the two towards the bottom of the board.

I had two boards where these shorted and had similar issues you have
now. About $2 to fix this or a rebuild kit from Ed at GPE.

Good luck,
Mike

[Joe_E...@hotmail.com]

I checked the two large resistors (R11 & R9) and they were 125 ohms and
1.796k ohms respectively, which looks fine to me.

Another measurement: I checked the voltages coming in from the
transformer and they were slightly high, 85VAC and 105VAC (Boy I wish
there was a little dial to adjust the voltage like old Bally games).

Any other suggestions? I'm open to just about anything.
Joe

[Joe_E...@hotmail.com]

I also checked the continuity of the traces, and they all look good.
The high voltage section looks like it's seen better days and has been
extensively repaired. There are two jumpers: between the non-bar side
of D4 and the barred side of D5, and between the barred side of D4 and
the adjacent side of R5.