TECH: Williams System 6 MPU

[Eric S]

Hello,

I have a Williams System 6 MPU for an Alien Poker that I'm having trouble
with. When the driver board is removed and the game powered on, it has some
odd behavior.

The upper LED doesn't turn on at all.
The lower LED will turn on, blink, and then stay on.

I'm not sure what is causing this; I expected that both LEDs would blink.
Any ideas?

thanks,
Eric

http://webpages.charter.net/strange218/pinball_website.htm

[AVP Pinball Division]

"Eric S" <estra...@charter.net> wrote in message
news:XFoes.13220$vv4...@newsfe02.iad...

Except when using Leon's test ROM the boards only function properly when
used as a pair.

--
Pistol Pete
AVP Pinball Division
Towson, MD
410-583-9200
web: http://www.AVPpinball.com
email: ser...@AVPpinball.com

[Eric S]

Update - I installed a working driver with this MPU and it booted up! Looks
like the upper LED was bad.

thanks,
Eric

"Eric S" wrote in message news:XFoes.13220$vv4...@newsfe02.iad...

[bara...@gmail.com]

check for cracked solder joint on the interconnect of the bad driver board.

[AVP Pinball Division]

"Eric S" <estra...@charter.net> wrote in message

news:fCBes.16436$NN3....@newsfe10.iad...

Once again: You can't test the MPU alone with System 3-6 games unless you
are using Leon's test ROM. With the stock game ROMs installed even a good,
working MPU will fail in self test when operated without a driver board
attached. These games were designed to work when the MPU/driver were paired
and the self-test requires communication from the driver board back to the
MPU. The odd behavior you saw when the two were separated and the MPU
placed in self-test was actually the correct failure mode as there was no
driver board attached.