Jumping in here, I'm Tazmancat's, um, pinball tech. Thanks for the replies and suggestions.

Addressing the speaker noise issue in case another WOZ owner in a similar situation finds their way here. The following thread provided the most insight on the source of the noise: https://pinside.com/pinball/forum/topic/wozecle-speakers-sound-tinny-buzzing

In the case of our WOZRR, the various digital noises coming through the speakers were very loud, louder than any other sound except for the jet engine noise coming from the cooling fan in the power supply. (JJP, seriously guys, spend a couple extra bucks on a decent temperature controlled fan for that thing. Maybe I got a bad one but I can hear it whine in my office down the hall. It's horrendous! Stock Chinese cooling fans are garbage, we know this.)

I started with the obvious, checking that all the connections were made, connectors correctly inserted, etc. The display power was the only loose connection. Not surprisingly, fixing this had no effect on the audio noise.

The noise is very much associated with the large bundle of wires running through the middle of the control box. Again, not surprising. Analog audio signals in close proximity (and running parallel with) digital control signals is not a good scenario. Those cables really need to run separate paths where possible and cross paths at 90 degree angles for best results. But it's an imperfect world so I did the best I could to isolate them as space allowed. It helped to cut the nylon ties and drop the audio cable down to the the bottom of the control box. The extra few mm made a difference.

In this case, the 3.5mm audio cable that connects the green audio output of the main board to the pink connector of the Pinovators board is the primary culprit. Rerouting that cable helped considerably but did not completely eliminate the issue. The thread referenced above mentions removing the audio filter from that line. That filter is not present in this machine but I happened to have a similar one on hand. Installing it reduced the remaining noise where it is not noticeable once a game starts.

I have ordered a very short 3.5mm cable to minimize the excess audio cable inside the control box. There's about 12" of excess right now and any extra cable in there is just going to pick-up system noise.

Clearly we have our share of (mostly minor) issues here. It's pinball, most of us are used to it. That said, once up and running this game is really nice. Smooth play and solid build. Also, very well packaged for shipping.

LTG, thanks for the quick response--late on a Fri. Top shelf, sir. Well done.