Re: Tech / help: MM display and power issue... AAarrrghh!

On Jun 12, 8:05 pm, "Dr. Smith" <TheLoose...@xxxxxxxxx> wrote:
I've been trying to identify just what happened to my MM during
shipping. When it arrived I opened the backbox and made sure nothing
obvious had come loose before turning I turned it on. Nothing looked
out of place and when 1st started up, it gave 2 bongs and prompted to
see the test report which said "sound board error". The display was
somewhat garbled and I figured at first it was just a loose ribbon
cable or some such as it "seemed" to clear up somewhat after reseating
the ribbon cables. I was able to run a few tests and for the most part
the DMD displayed properly with a few stray dots and I cycled through
the coil tests ect ect though the DMD was still acting strange. It
looked like images were superimposed one on top of the other along
with a lot of extra garbled dots. Occasionally a screen or two would
come up perfect looking though. (Corrupted data on the display chips?
Extra uncleared data still being displayed?) Also, the DMD is new and
was working prior to shipping.

The next morning I fired it up and the display was really garbled to
the point where I couldn't access the tests or anything as nothing was
legible at all (MUCH worse than previously). I reseated all the
connections to no avail so I took out the sound board to see if there
was some cold solder joints or something that was causing the problem.
I dont think the ride down was a real smooth one, so I could imagine
that some solder joints could have cracked or some such. I didnt test
any, but they looked good for the most part to my naked untrained eye.
I replaced the board and NOW got THREE bongs on boot up, and I check
to see if the u3 (and u2) is seated good and then restart it to see if
I have any luck getting to the test menu but the DMD is too garbled.

At that point, trying to start a game on the push of the start button
yielded one bong and some sort of reset as soon as the ball is
launched, and then all the sound dies. The led on the sound board is
not blinking as (I thought) it was supposed to. I turned it off and
tried to see what I could find online... come back after a few minutes
and turn it back on and now it gives no bongs at all at start up, the
DMD stays dark and the only lights that come on are the coin mech
lights (The backglass was off so I don't know about them) so at that
point I just unplugged it.

I'm not a tech by any means and am at a loss as to whats wrong.
Looking online seemed to suggest that some of the sound/display chips
were corrupted, and that might explain the garbled display, but I
wouldn't think that would account for the game not doing anything at
all at this point. (My 1st thought was a fuse, but I checked the ones
I thought could possibly cause this and they all tested good.) Also
whats the likelihood that the chips get corrupted during shipping?

So as it currently sits, the game gives zero bongs when its turned
on, the speakers are getting power and the coin mech lights work, but
that seems to be it. The LED on the display board does not light at
all now. The blanking LED on the CPU board lights up solid when turned
on (with zero bongs) and the other two LEDs don't light up at all.
(This means the cpu isn't getting proper voltage?) All the connections
have been reseated along with a couple of the chips on the sound
board.

Anyone have an idea of what happened or what I should look at or try
before havin' a professional look at it? (Also, I don't have another
machine to switch board with to try.)

Here is an image of what the DMD was doing before the "black out":http://i172.photobucket.com/albums/w12/Dr_Smith_bucket/mmdmd.jpg

Any help would be awesome,

-Doc

There is a problem with MM sound chips. Somehow, one of the ROMs loses
a couple of bytes which can lead to sound problems - but not the stuff
that you describe.

I would check that all the chips are seated tight on the CPU board.
You can lever the chips up just a fraction with a screwdriver, then
push them home again.
That's the first step, along with another round on the connectors -
specifically the ribbon cable from the WPC to the AV board.

.

Loading