I ended up purchasing a tested working system 9 mpu complete with roms. Installed it into my game and get code 7. I place my old board back in and it boots up every time. But has other issues that I have given up on.
So..... Is there any preliminary things gs I can do before sending it off again. I do not have an o scope.
Quoted from Fordiesel69:I ended up purchasing a tested working system 9 mpu complete with roms. Installed it into my game and get code 7. I place my old board back in and it boots up every time. But has other issues that I have given up on.
So..... Is there any preliminary things gs I can do before sending it off again. I do not have an o scope.
I'd question the "tested, working" assumption. Did you by chance try moving the ROMs from the correctly booting old board into the "tested, working" board to rule that out"?
Yes I did swap my known good roms over. Sockets were nice and tight.
Everything the person stated that was done to the board was done. They even tested it for a bit before shipping it.
Here's one thing you can check with a DMM/Voltmeter: Microprocessor U17 should receive +4.5VDC and no more than 0.005 VAC ac pins 8 and 35. If this is the case, replace crystal U21. (from pg 50/51 of http://gamearchive.askey.org/Pinball/Manufacturers/Williams/pdfs/pinball_troubleshooting_sys9.pdf )
Quoted from wayout440:Here's one thing you can check with a DMM/Voltmeter: Microprocessor U17 should receive +45VDC and no more than 0.005 VAC ac pins 8 and 35. If this is the case, replace crystal U21. (from pg 50/51 of http://gamearchive.askey.org/Pinball/Manufacturers/Williams/pdfs/pinball_troubleshooting_sys9.pdf )
Think there should be a decimal point in that 45V somewhere...
It was a dead crystal. Swapped it from another board and all seems well.
What causes a crystal to fail, I have never heard of this before. It seem to be mentioned a lot with williams boards.
Quoted from Fordiesel69:It was a dead crystal.
Wow, certainly a new one in my book! But then again I prefer Ballys.
How did you determine that was the culprit?
My probescope showed nothing on clock pin of both the sound CPU and main CPU. I also pressed the sound test button and got absolutly nothing. That meant both CPUs were not running.
Quoted from Atari_Daze:How did you determine that was the culprit?
The link I posted earlier in the thread indicates the primary causes of error code 7 on Williams System 9 and measurements that point to crystal failure.
There are many failure modes of CPU clocks. One of the first things we were taught in school was to test power and clock on CPU based systems before doing any other troubleshooting.
Mostly aging: Stress to mountings and contacts may relax over time or be damaged by vibration. Contaminants absorbed into the crystal changes its mass and many other causes. Then in other cases they run for decades without a problem.
I've been working on a boot problem with my Comet on and off for some time. It has a previously repaired board with alkaline damage. When I would first turn it on, it would light up but not boot. If I would let it warm up a little, I could turn it off and on and it would sometimes boot but with no sound. Turning it on and off again it would boot with sound and work perfect until I shut it down again. I've done quite a few things and spent quite a bit of time trying to fix it.
Thanks to this thread, I just replaced the crystal and now it works perfect. Thank you Wayout440 and Forddiesel69 and thank you Pinside.
Quoted from PinFever:where do you find this crystal online and product code would help greatly
Quoted from Mbeach:Where would the crystal be located on the comet machine. I have the same code on mine.
Mid right side of the MPU. Will look like a small metal square. U21 -
Manual here: https://www.ipdb.org/files/548/Comet_manual.pdf
PDF Page 33
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Berea, OH