Hey bud. Congrats on the GL! I'm a new owner also and have been playing it and fixing it in combo. It is very addictive!
So similar to yours except yours has nicer playfield I think.

When I got mine home I noticed right away I had no displays and no bongo drums too. I bought it on the street corner as "working". .. I have all background target sound effects though which I'm happy about.

So after realizing I had a stitched together pin bot powersupply board and it was beyond what I wanted to spend time on I bought a new xpin power supply board - just like I did with my other game SS. It is a great product and I'm a firm believer in having a rock solid powesupply on these older timer machines...

I did check the pinbot board high voltage side and got 93v +\- so it seemed all good. But I ordered the replacement board anyways. Sooooo I put new board in and presto all displays work perfectly!! Still no bongos though...so only 1/2 way there.

Just thought I' d let you know my partial success. Your thread is perfect timing, so I will be following closely. Going to check my U5 chip temp. I have combed all old threads on no background music on GL and high speed because they had the same music board and more HS made...lots of info but nothing definitive. Wish I had a reversed cable, but no..tried that! oh well. Hope we get it sorted out and you get your flippers fixed.

It is a two-stage flipper button right? Light pressure activates lower flippers only. So I bet you have a) grubby wiring to clean as mentioned and also b) all flipper button switch blade contacts that needs a good de grubbing and light flex stone. Bet that does the trick.

Did you measure the coil resistance? Maybe it is clapped out? Just a thought.

Right on! That is a great find...nice straightforward fix. I'll be very interested to see how your new sound board goes when it arrives.

I'm looking at the first photo you linked in post 1 and I cannot be sure but your power supply caps look original. The two parallel black ones as I understand it they do get old and need replacement., I think your display problems might be related to the power supply as mentioned above.

Also, my sound board looks exact like yours ...meaning the big cap in the middle of the board looks burnt or at least stained from heat coming from the bank of ceramic resistors below on the CPU board. I'm guessing decades of heat exposure like this affects the chips and cap on the sound board. I may try to replace this cap and see if any solution here. More troubleshooting this weekend.

Ceramic, cement, yes those ones. I know they are supposed to get hot. But what is the heat effect on other components right above them over years of use? As you can tell I'm not an expert and just learning the terminology. Good thing you're along with us WO to keep us on track thanks!

I was certainly eyeing those replacement display kits too, but in this case fluked out with my new power supply board. Ymmv of course.

Just for the record in case it comes across like I'm trying to start an argument here...I'm not. I'm also not saying to replace the cement power resistors for maintenance, that would be silly. ...carry on.

Hi,
Man, that sucks your new board did not solve the problem! What a downer, but, it is at least a slow process of elimination. I'm not very useful to your questions, sorry.
Have you read this thread? It is the most thorough thread on this specific game/board I have found in my research....unfortunately for us, it was just a reversed cable! A lot of useful troubleshooting info though:

https://pinside.com/pinball/forum/topic/williams-system-11-missing-background-music-investigation#post-2295117

I'm along on this journey also with the same problem, so I hope together we can solve this! Weekend coming up means good troubleshooting times.

Among other error messages I get on start up that I'm dealing with, I get adjust switch 23 - 4 bank. Are you sure yours is switch 4 bank four? Maybe we start with the easy stuff eh? I forget, do you have a copy of the manual for this game?

Just as follow-up on this thread, I took a chance a few days after you ordered a sound board. I ordered one direct from pinballpcb, and finally installed it yesterday .....and....
The bongo drums pump out the beats! It was a blind attempt for a fix, and, in this case it worked. I hope your resident board expert can help you Luzur, it seems you may have some problem on the cpu board that you and I both don't yet understand.

Btw. As soon as way out mentioned a logic probe above, I was thinking to myself ...hmmm another piece of hardware to buy and get familiar with. It seems a whole new language to me on some of the troubleshooting threads I have read, and grateful that others like WO have the skills and willingness to help us newbies. Trust it will all work out for you, just keep at it...it is worth it! I love playing GL, very fun game.

Hi, it was plug and play.

Thinking about it a bit more about your error question on start up, since your lower displays are out you won't be getting the 2nd half of the error message. So mine with all working displays says error four bank 4 on the top 2 displays and 23 below, so that is switch 23 on the 4 bank drop targets up top...according to the manual so without working displays it is a bit awkward to find out which target is not working. The 23 is listed on the lower display...bottom right but your display is not working.

I have the error message mentioned, and I have yet to dig into it but I'm confident it will be something straightforward like a dirty contact or broken wire...you may want to hunt around for the obvious.

So we are at a cross roads right with your machine. You and I don't know how to take on a cpu board and such with IC soldering, logic testing, etc so that leaves 2 options. 1. Send it out to pros 2. Replace small aux boards as troubleshooting points to obvious "suspect" areas.. Or combo of both ..so that would be 3 options..

Obviously all options can be expensive and I'm not saying to buy a new cpu board just because!!!

I still think you would be best to start with your power supply board. Either get it tested / rebuilt or replace with something like an xpin board. Without steady, proper voltages coming into the cpu, any problems are likely compounded.
Do you get a flicker at all of the lower displays?

I look at it this way...
You have a super playfield on that machine, and it is a great game. So why not invest in it.
If you can afford to fix it, you should. Just a lesson in patience... keep at it man! You'll get it sorted out.

Party!!!
Sweet price too, more left for beer budget!
Now all you need is the displays. Did you order a new power supply? Did your board expert have a look at that board also?
Prepare for some bongo fury!

Mine "whines" away in concert with the pulsing of lamps in attract mode. My other sys 11s do not do this. I chalk it up to earlier cpu design and grounding...I'm not worried about it. If you watch Todd Tuckeys videos on GL on YouTube in their shop, they also make this noise.