I'll do more testing tomorrow, but at least I know the onboard oscillator, meters, groups, main buss, channel 8 and the cue and echo busses are passing audio...
So I was going through old threads of mine updating links to pics and vids and such...I thought I had linked a video tour of the Model 5B I captured sometime ago in this thread, but I don't see it...so here it is for future generations...