I have a similar problem suddenly on my AFM, did you ever fix this issue?

The OP replaced parts that had nothing to do with the issue.

The board has 4 1uf caps that are in the audio path. They can fail, but usually this results in either the cabinet or head speakers being weak. Replacing these might help.

—
Chris Hibler - CARGPB #31
Http://chrishiblerpinball.com/contact
http://www.PinWiki.com/ - The new place for pinball repair info

Thanks Chris. The sound on both the cabinet and head is low, unplugging either has no effect on the other. Looking at the component list on that board I don't see any 1uf cap, can you point me to the right one? I also checked voltage at J605-7 and -11 and got 13VAC vs the 18V that the manual states, do you know if this is normal or a sign of an upstream problem? Thanks.

67110915394__6E68060D-3B27-454A-9728-360B78C4163D (resized).jpg

IMG_7116 (resized).JPG

C38, C39, C43, C44

Do you have aftermarket speakers?

Aftermarket speaker in the cabinet, stock in the head. Worked fine until yesterday although I have had it powered down for a few weeks working on refurb.

13V vs 18V could be the issue.
You didn’t swap transformers, did you?
—
Chris Hibler - CARGPB #31
Http://chrishiblerpinball.com/contact
http://www.PinWiki.com/ - The new place for pinball repair info

No, didn't do anything transformer related but I will start looking at all the supply wiring and see if something is amiss.

The pre-DCS transformer nominally outputs 18VAC. The DCS and WPC-95 transformer nominally outputs 13VAC. I'm pretty sure the manuals are incorrect.

Yep DumbAss , you are correct.
OP can ignore my prior post.
I had forgotten what I well know.
—
Chris Hibler - CARGPB #31
Http://chrishiblerpinball.com/contact
http://www.PinWiki.com/ - The new place for pinball repair info

I just discovered the 3" tweeter has no continuity so it needs to be replaced. Could this cause the whole system volume to drop?

Ok, so I finally figured out my problem and despite the embarrassment this will cause me, if it saves someone else from my mistake, so be it. A previous owner has installed a potentiometer to control the volume in this machine. I did not realize that it only connects to the speakers in the backbox, I figured this out today while tracing the wiring. I also did not realize that the adjustment buttons on the coin door control overall volume, I'm guessing the pot was to turn down the high frequencies while having the cabinet speaker loud for lots of bass. Anyway, at some point of messing around I must have inadvertently turned down the volume with the buttons, probably while trying to work through the menus with the display disconnected. I turned it back up and miraculously everything is fine. Now I just have a tweeter to replace so at least this led me to that problem. Thanks for the advice along the way.

Thanks for posting the solution.
That’s one we never could have helped you find.
—
Chris Hibler - CARGPB #31
Http://chrishiblerpinball.com/contact
http://www.PinWiki.com/ - The new place for pinball repair info

I've got an A-16917 DCS board that had some previous work done on it (of arguable quality).

It had really poor quality sound, noise and low volume output. Started working on it and around some of the issues created by the previous board work.

Replaced C20, C21, The TDA2030A's at U27 and 28, the TL084's at U21 and U29. I also replaced all of the resistors and capacitors in the low pass and high pass filter sections. Toned all the connections out, confirmed the resistors.

The sound quality is great. The cabinet speaker is nice and loud but the volume output out of the backbox speakers, though clear is at a much lower volume than the cabinet woofer.