Mr. Ross has likewise replied to me with essentially the same information; i.e., electromechanical relays, not solid state ones. He assures me it is no different than turning a light switch on and off.
Just to add that the very first batch of Analyser Pro/StopClock Professional did use triacs but we reverted to electromechanical relays as some enlargers didn't like the triacs very much - specifically the LPL 5x4 which has its own relay. The leakage current through the triacs was sufficient to keep the LPL's relay closed when switched off - obviously it was a very sensitive relay! If you can hear a "click" when the timer switches the enlarger on or off, then it's NOT a triac model.
I was going to post Richard Ross' email back to me with his permission (which he granted), but his post above is even better!
Thanks to all that contributed. All questions answered. :cool: