Just curious why you would want/need to go this far in depth to test a sys11 sound board. What are you looking for specifically that the test switches or audits can't do for you? Not trying to be a jerk here, but you can generally rule out sound board vs mpu issues with what's already available (test eprom). If this comes off sounding dickish, I don't mean to be.

As far as debugging the sound boards, there isn't a whole lot going on with them that would need such an elaborate testing device. The only issues have repaired have been blown power amp transistors, bad caps, and the occasional failed opamp. I don't even think I've ever run into a faulty sound EPROM. The FM chips hardly ever fail (At least I've never seen a failure on one), and debugging them is pretty black and white from my experience.

I usually have them all on the bench at the same time, so I guess that's why I didn't think of that.

As far as a testing rig, the easiest way I can think of would be to use a RPI or PI Zero or something with a small footprint and connect GPIO outs to the data lines to trigger stuff. Less work to write a small program to control it vs building stuff from logic ICs and switches, unless it is trivial to trigger them.

That certainly makes building a little interface a lot less technical. So in this video, it is really is nothing more than a 8 pos dip switch interfacing with those pins and a momentary trigger to ground. If I were you, I'd just manually trigger them with like breadboard leads or something vs even wiring up switches + socket on to a pad-per-hole board or something.