John, my instruction manual says pin 21 not 23.
Yes, it's pin-21, that's just a typo, the brain wasn't engaged when I posted. 
I've read this whole thread. Fascinating how much the technology has progressed during the last thirty years. Waiting for the successful conclusion.
I obtained a TAS Chuff-n-Puff kit, I'm going to bench test it. If it works, I'll use that. If it doesn't, I happen to have a product that I can use, my very own Super-Chuffer. In one way or the other, I'll ship a working engine with chuffing smoke.
It use to be interesting trying to salvage those old boards, but when they are so hard to work on, or so obsolete...I lost interest. Going Cruise CDR or just upgrading an old PS-2 5V is the way to go in my opinion. G
Trust me George, I wasn't that interested in screwing around with these! It's just that I have a repair and I didn't want to stick him with a big bill to upgrade to all the ERR stuff, and then I'd still need to solve the chuffing smoke issue! It was kind of a ****ed if you don't, and ****ed if you do situation.
