WPC DMD display problem
Joe_E...@hotmail.com
I've been piecing together a WPC game (Doctor Who), and today's problem
is the DMD. When I power on the game, the CPU is running and I get a
beep from the sound board, but all I get on the DMD is a jagged,
disconnected line. Here's a picture of it:
http://home.comcast.net/~joeentropy/DMDproblem.jpg
A few facts: The Dot Matrix Controller board was bought off eBay
supposedly tested and working, but who knows (it had a 4A fuse in it
for one thing). The lower fuse is the proper 3/8A value, but the upper
one is currently 1/2A (because I couldn't find a 3/8A in any of the
crappy stores around me, so I have to order some off the Internet). The
DMD itself is brand new, just bought from Marco at the Allentown show.
I've checked the ribbon cables to make sure they're plugged in
correctly, and they're all new cables courtesy of Great Plains
Electronics. I measured the voltages from J604 on the driver board, and
they're all pretty close except for pin 8, which is 0V instead of the
expected +62V. When I swapped the old fuse with the current fuse, the
heretofore unlit LED on the controller board lit, which I took to be a
positive sign.
Clearly the 0V is bad, but would that cause this kind of problem? When
I get the proper fuse, is it likely that the 62V will come back? Any
other good ideas?
Thanks,
Joe
martin
supposed to melt and protect your electronics. In this case, sounds
like the fuse is fine. New fuses won't help.
Check the ribbon cables, reseat any socketed chips and so on. But at
first look, the board is probably eBay quality.
easternpinman
check transistors Q2,Q10, Q3 resistor R11 zenner D3 that are first
failure parts ,,,,
Marius
www.pinball.ro
Joe_E...@hotmail.com
"it is tested and Working" said the item description. Maybe I should
have looked for one that was working _correctly_.
easternpinman
Marius
www.pinball.ro