Re: Doctor Who slow DMD and some gameplay

I'm not sure if Clay's guide will help in this case. You've got something
bringing down the Data line and I don't think Clay's guide goes into that.
What I ended up doing is following the Data line back through the
Fliptronics board and found two chips that were causing the problem, a
74HTC244 and an 74HCT138 if I remember correctly.

My best advice would be to look at the schematics for where the Data line
goes into the sound board and take an ociloscope to chips that the Data line
hits first and compare them to your good board since you have one.

One other suggestion if you don't have an ociloscope is to take the board
out of the game, and put one lead of a DMM to ground on the board and check
each odd numbered pin of the J903 ribbon cable header for continuity.

If you have continuity to ground on one of the odd number pins on the header
then follow the schematic and do a continuity test on each leg of each chip
in that Data line. If you find a leg of the chip that beeps to ground on
that Data line then that chip is likely shorted to ground at that leg and
will need replacing. This technique will of course only work if you've got
a chip shorted directly to ground, which is what sounds like what's
happened.







"PinballGeek" <PinballGeek@xxxxxxxxx> wrote in message
news:1189349286.494249.285400@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
I disconnected the Fliptronics cable, but it made no difference.
Seeing as how one of the data cables went from the CPU board to the
Fliptronics board to the sound board and then the DMD controller
board, I went ahead and disconnected the data cable from the sound
board. Bingo, game plays fast and display looks great. Of course, to
get that, I just have to give up sound. :)

I can switch out the bad sound board with my other DWs sound card, but
I really should troubleshoot the existing one to see what may be the
cause. Should I just start with Clay's guide and go over the sound
section to try and isolate what could be causing this? Is there
another way to go about trying to determine what on the sound card
could be the culprit of this?

Robert

On Sep 8, 6:01 pm, "Borygard" <boryg...@xxxxxxxxxxxxxxxx> wrote:
I've had something very similar to this that turned out to be the
Fliptronics board.

When the Fliptronics board had the ribbon cable connected the game would
run
in slow-mo as you describe with some weird stuff happening on the DMD.
It
turned out couple of chips on the Fliptronics were bad and bringing
everything down, but the game would play strangely slow.

Disconnect the ribbon cable from the Fliptronics board with the power
off,
power back on and see if the game plays normally.

"PinballGeek" <PinballG...@xxxxxxxxx> wrote in message

news:1189277725.824812.87340@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

I just got my second Doctor Who pinball machine last week, and I have
a strange issue that I am hoping someone can point me in the correct
direction in solving. The game display just seems to run slow. This
is my second DW (this one has the factory installed moving Dalek head
and is in much better shape than my first DW, my first pin), and so I
know roughly what the speed of the game should be. The first clue to
I had to how it was behaving was right off the bat, the ball gets
plunged, and it took more time that normal for the ball to pop out of
the Tardis and for the sound to play. Normally when the ball goes
into the Tardis trough, it pauses maybe 1 second total before shooting
the ball out. My new game takes 3 seconds or more it seems to pop
this ball out. This happens not only at the start of a ball, but also
when the ball goes into the trough via the left loop. I thought it
odd, but kept on playing. I then noticed what appeared to be a
flicker in the DMD. After looking closer, I noticed that it wasn't
exactly a flicker, just slow screen draws.

When the display is static, it looks great, no moving lines or
anything, but when it transitions to a graphic, it does so very
slowly. Finally, the dead give-away was the video mode. If you
haven't played it, you run away from a Dalek and jump over stuff to
get to the Tardis. Well, that ran at about half speed. Being a
computer programmer, I found it odd that even though he was running
slow, the graphics moved slow, pressing the buttons at the right time
still allowed you to complete the video mode successfully. I
originally thought somehow my DMD was slow to refresh, but seeing that
the button timing was matching the slow DMD, I figure that somehow the
CPU is running slow, all at some lower clock rate or something.

I have done some troubleshooting, but I still don't know what the
issue is. Here is what I have done:

1. Replaced the CPU board
2. Replaced the Dot Matrix Controller board
3. Replaced the ribbon cables
4. Replaced the DMD
5. Checked the power driver board voltages. The only one that was low
was TP8, which was 15V w/ all the lamps flashing. When I removed most
of the illumination connectors, the voltage was at 17V.

Having done all of that, the game behaves exactly as it has, slow
display drawings. At this point I am at a loss as to what to look at
next.

Having a second DW still in my possession has made eliminating
potential issues much easier, but I am nowhere close to solving this
yet. Any ideas about what could be causing this, what to look into
next would be much appreciated.

Robert Harris
TS*PP, LO*TR, D*W
3 down, so many more to go...




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