I have a Nava with a similar issue.
Powers on and the Start button is flashing along with Pattern Play, but when I hit play, the start button goes solid, but the sequencer doesn't play.
If I hit stop, then stop lights solid and start flashes again.
All ICs are correct. I've tried reprogramming quite a few times.
No voltage at TP1, but I get teh right voltage at +/- 15V
Finished Build - Init EEprom mode & TM2 adjustment [Solved]
I’ve got a working Nava but no accents. Tried three different sets of mux boards and all sounds mute when IC 111 and 114 are populated. Without, works normally just no accents. I can’t get a good reading at tp1. Less than 1v. I checked when I first powered it up and it was fine at 5v then spent a few weeks troubleshooting some voices. Now can’t get it past .5v. Pretty sure my mux issue is related but can’t see anything wrong in sequencer section.
I feel your pain. The mux boards were driving me mad for days. I had exactly the same symptoms that you described. Eventually i bought a set from Klanggenerator and everything just started to work. I could never narrow the error down. Another option would be to get a set of throughhole mux boards from oshpark.
I’ve done the two different oshpark versions, no change. Going to dig deeper this weekend. I did have a bad chip ic112 I think that wasn’t triggering snare. Swapped and fixed, so there may be others.
Aargh, sorry to hear that. You can always try to get some from Klaggenerator, but the feeling of not being able to fix this yourself sucks :/