About me: I am a pinball hobbyist and have dabbled in board repair/troubleshooting. But, I have only been in this hobby for a few years. I am a mech engineer by profession and I bought a nice soldering station so I can be very dangerous! I am comfortable replacing components on a PCB (I have worked on old gameplan boards, late 80s Bally boards, and WPC boards). I can fumble through schematics, but I am learning still.

About my Sorcerer: I bought it 2 years ago and it has basically been running / playing fine ever since, except one small (but growing) issue where the power seems to stutter intermittently. The stuttering occurs any time when the game is turned on (attract mode, during gameplay, etc). It seems to come and go with the weather. For example, the issue did not happen at all last winter, but came back this spring when it started to warm up in my basement. When the stuttering occurs, it seems like everything with power is affected (GI, insert lights, flippers, displays, etc). Also, the relay on the MPU (K1 if I remember correctly) clicks along with the stuttering. I have been reading up on sys 9 issues over the last couple years and have tried a couple fixes. 2 months or so ago, I removed the MPU and PSU boards to my bench for visible inspection (basically looking for cold solder joints since I have heard these are an issue on this era games). I found nothing on my MPU, but my PSU had a bunch of cold cracked solder joints. I was unable to melt the solder and remove it completely, so I just tried to add solder to fill in the cracks thinking it would atleast get me by. I put the boards back in and hooked it all up and the machine was locked up. Error 7 on the MPU. Reseating all the connectors and messing with stuff unlocked it and I was able to start a game. But, the stuttering issue remained. Next, I bought a new big electrolytic cap for my PSU and swapped it in. This time, the machine locked up again with an error 5 on the MPU. This time I was able to unlock the machine by going into the game setup mode and coming back out. It seemed to revive it, lol. The game plays fine, but the stuttering issue still remains! My next idea is to completely rebuild the PSU knowing that this is just a shotgun approach. My friend told me to look at cracked solder joints on the K1 relay on the MPU and to watch the blanking LED on the MPU when the stuttering occurs.

So, this is where I am at. I am scouring the web looking for ideas. Again, I am still learning so my troubleshooting and root causing electronic issues is still in infant stages at this point. I do not see a williams sys 9/11 troubleshooting guide on Clay's page but I keep seeing reference to it on pinside. Does anyone know if it is posted somewhere?

Here are some pics. Will check out the blanking circuit next!

20170519_203825 (resized).jpg

20170519_203830 (resized).jpg

20170519_203837 (resized).jpg

20170519_203856 (resized).jpg

So I get nothing with the probe on U22 pins 3 or 7 when machine is powered on or when i start a game...

14952421937651849574061 (resized).jpg

pin 3 u22 reads 4vdc and the base of q6 toggles between high and low on the probe. still nothing on u22 pin 3 or 7 with the probe. Here's footage of the probe measurements... https://www.dropbox.com/sh/2eumzh74g2i9gey/AAAbMNtEre6LcitQoKEGKhNpa?dl=0

On the schematic pic above, next to the word "blanking" what does "2B4" mean?

Ok it looks like it just means mpu schematic sheet 2, sector b4, for continuation of the blanking circuit...

So I measured 1J17 pins 4, 5, and 6 at the CPU and read 5vDC. At the same pins I am reading 1vAC. Is this too high of AC ripple? Do the 2 smaller caps on the PSU feed into the ripple? I replaced the big 18,000 uF cap but not the 2 smaller ones that are the size of AA batteries...

All lamps are working and the game plays 100% except for the power stutters whic happens midgame or when a game is not even in process. Not sure what you mean by "7408 chips that AND blanking with signals are heating up."

Just for my own learning, is 1vAC ripple on the 5vdc into the mpu board ok?

I just ordered all the caps to shotgun all the electrolytics on the PSU. Will report back after that's complete. Happy to try any other measurements, etc, that anyone can suggest while waiting for them to arrive...

Hi @vid1900, I replaced the 18000 ufd cap already. Replacing the rest next...

Seems like a few chips are getting warm (u8, and u60) but not hot. I recapped the entire PSU and the ripple is gone now so that's good. Still getting some stutters but it seems less frequent now, weatger related? A few of the caps on the MPU look swollen. Good idea to replace these too? I am still getting no reading on u22 pins 3 or 7 with the probe.... Any other ideas on what I could check?

ok I know it has been a while, but the sorcerer seemed to play fine for a while during the summer. Now that the cold, dry months are back the stuttering came back. I recapped the entire power board and that did not help. Just tonight, I replaced all the electrolytic caps on the MPU board and reinstalled it. The stuttering was really bad when I first powered on but I was able to navigate through the menus to set the game on free play and start a game. The power stuttering was worse that it ever has been. But, over the hour that I was messing with it, the stuttering got progressively better until it was completely gone. I am not sure if it was because the room was warming up though and the issue is aggravated by cold air temps. It is so weird. When the power stutters, EVERYTHING stutters; lights, flipper coils, sounds, etc, but the game does not reset. Could this be a clue?
NOOB question: When I replace all the capacitors, do they need some time to charge in order to work properly after they are initially installed? Could it be that over the hour that I messed with the machine that the caps all charged up? Ugh, I know it is a long shot and that my troubles are not yet over. If there is anyone still following this thread, I am desperate for what to try next... Is there a chip on the MPU that distributed power to everything? The relay was clicking too...

The weird thing to me is that the cpu is not resetting when the power stutters. I can continue my game with the power stuttering. I will absolutely check your suggestions above. This morning and after work I tried it out again and no stuttering this time.
Was I way off track in my thinking that maybe the new caps needed to be charged???

Ed, yes I replaced all the electrolytic caps now on both the power supply and MPU boards. Since replacing them all on the MPU board last Thursday night, I have left the machine on all of each day over the weekend to monitor behavior. The stuttering was really bad on thursday night immediately after recapping the MPU and initially turning it on. But after an hour or so of it being powered on, the stuttering stopped and has not re-occurred since. Two times now, however, after the machine has been on for a few hours and working normally (attract mode, game play, etc) I noticed that the machine would go to sleep (sort of). 00 is displayed on player 1 score display and the game is locked. CPU diagnostic LCD says 0 but a game cannot be started and even the CPU reset switch does not work. The only thing that worked in this state is the sound test so not sure if that is a clue or not. The machined returned back to normal both times by simply powering it off then back on.

My next step in my shotgun blasting attempt to get this machine back to 100% (I consider it 95% at this point in time) is to replace all the interconnects as suggested by Cheddar and snyper2099 above.

Any other thoughts or suggestions are still appreciated. Thank so much for the help so far!

Thanks @cheddar. Total N00B question. The wiring diagram is shown below. Is the circled area an actual interconnect plug that I should look at? Seems like this corresponds to one of the harness connectors connecting from the head to the cabinet. Also, this one contains all the switch rows as well as the flipper signals all of which could be what was stuttering (insert lamps, flippers, etc).

pasted_image (resized).png

Finally got around to repinning the male pins of the interconnect (could not figure out how to remove the female pins ). I think this did it!!! Makes sense that either the power or ground connection on this connector being loose would cause the issue I experienced. Thanks sincerely for the help on this!!!

I have the pin removal tool shown below which worked great for the male pins but did not seem to fit in the hole or over the OD of the female pins. Is there a different tool for the female pins perhaps?

https://www.amazon.com/gp/product/B0094MIS9U/ref=oh_aui_detailpage_o04_s02