On Tuesday, March 7, 2023 at 2:55:35 AM UTC-5, John Robertson wrote:
On 2023/03/06 1:22 p.m., Ethan Winer wrote:
On Sunday, March 5, 2023 at 7:12:16 PM UTC-5, John Robertson wrote:
On 2023/03/05 3:04 p.m., Ethan Winer wrote:
My vintage Gorgar mostly works well. It's a great machine, and I even added a subwoofer for a realistic heartbeat! But I have the strangest set of seemingly unrelated problems. Several years ago I replaced the florescent displays with a modern LED
version. Last year I replaced the CPU and driver boards with the Rottendog MPU327. I'm not sure if these problems started with the Rottendog swap or earlier, but I returned the Rottendog board and the replacement has the same problem. So it's probably
not the Rottendog board. I since replaced the power supply, which didn't help either. Here are the problems, and hopefully someone here will have some troubleshooting suggestions:
Going through the A, B, or C rollovers at the top registers multiple times. So instead of increasing the exit bonus by 1 point (3 for B), it advances by 1-4 at random. D and E at the bottom of the playfield also advance more times than they should.
Completing A, B, and C for a 2x exit bonus often rings up twice making the bonus 3x.
Each time a new game starts there's no heartbeat. Then once a few targets have been hit making their sounds, the heartbeat starts up and stays on through the game.
The score displays for players 1 and 2 track correctly. But for players 3 and 4 the score keeps "slipping" and loses points. I'll have 150,000 points, then suddenly it shows 125,000. Then as play continues the score goes up again, randomly jumps to
the correct number, then loses points again. The CPU knows the correct score, because if player 3 or 4 wins, that player's number flashes as the winner, even if the final score displayed is much less than players 1 and 2.
All of the A-E rollover switches appear fine, and all of their diodes are working. Further, A-E do not all share either the same row or column.
Any ideas will be greatly appreciated!
Sounds like a driver board problem to me. Did you replace the driver
board when you got the new MPU? The Molex interconnects can fail over
time leading to erratic operation sometimes...
What about the Switch Test? Do you only get get one registration for any >> of the A, B, or C rollovers or does the display flicker while you hold
the wire actuator down?
John :-#)#
--
Thanks John. To be clear, the Rottendog MPU327 is a new board design that replaces both the CPU and driver boards with a single board. So there's no Molex connector as in the original board pair. I tried holding down the A rollover, and indeed it
continues to register. Though not quickly in succession. When I first press it I get 2 or 3 hits, then a second or two later it registers several more, then a few seconds later a few more, etc. So it's not switch bounce either. Again, this is just one of
several seemingly unrelated problems.
You wrote above, "(Please post followups or tech inquiries to the USENET newsgroup)" Am I posting in the wrong place? Is there a better place? I used to post here years ago, but I haven't kept up with pinball groups or forums.
Hi!
It sounds like the switch response is noisy if you are getting multiple closure indications while holding it steady closed.
Do other switches behave the same way?
Out of curiosity, did RD use 74HCxx(x) or 74HCTxx(x) chips for the
switch matrix? I've had trouble in the past where they used 74HCxx(x) instead of the correct 74HCTxx(x) chips! took me the better part of an afternoon to catch that one on one of their boards (for Space Station)
that had an erratic opto problem.
You are posting on Usenet RGP newsgroup - you are doing just fine! I
assume you are coming through Google Groups - that should be called
Google USENET Groups but they didn't bother with the USENET part of the name...
John :-#)#
--
(Please post followups or tech inquiries to the USENET newsgroup)
John's Jukes Ltd.
#7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3
(604)872-5757 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."
Thanks John for all your help so far. All of the logic chips on the entire board are labeled 74HCT## so it's not that. I also have the same RottenDog board in my Firepower machine, and that works fine. These boards have ROM code for a dozen or more
Williams games, and you tell it which game it's in via DIP switches.
There are several other problems unrelated to the rollovers, so I thought it might be a grounding problem, or a flaky ground connection. The last problem I mentioned initially, where the displayed score for players 3 and 4 "slips" and losing points,
started when I replaced the power supply hoping that was the problem. I've wiggled all the connections, unseated and reseated and sprayed all the Molex connectors inline between the upper box and lower playfeld. I've seen (and fixed) a lot of
issues with my machines, but I never saw anything like so many unrelated problems!
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