Yes, that is the closest match to your version of the board. I need to add the 555 circuit to that one (it is mostly independent of the rest of the board, so it should not be what's giving you issues here. One additional thing I would check here is the LS612. I get way too many weird symptoms from bad 612 chips (About one in six of the NOS chips I've picked up for these was bad).
Can you suggest a source? I bought 4 on EBay and eight from an electronics store in CO and still don't have one that works 100%.
Sent from my iPad using Tapatalk