Six days later, and we have a result!
The cash acceptor is powered from a N/C contact on the coin relay. As soon as a play was registered, it opened, and not only dropped the lockout coil, but disconnected the coin fingers too.
A simple link was soldered in, and now tokens AND cash can be played as you see fit.
While the coin mech was out, I noticed that THREE coin fingers were still fitted, the middle one, for 6d, having no wire connected.
This set me wondering if sixpence play could be resurrected. I remembered that I had a spare 3-way acceptor of the same type, recently serviced by Steve at Swallow Amusements. A few bits needed to be swapped over, but otherwise a perfect fit.
The missing wire was more of a problem. There was no indication of where it went, after it left the coin finger. The other two were connected to the usual type 1s/2s change unit, with the output driving the credit counter; but for a single play, I looked towards tripping the token coin switch.
This was odd, in my experience. It trips the credit counter from the back contact, the N/C one. The coin OPENS the contacts as it passes, and the counter trips when it falls back. I tried the new wire on the back contact, and YES, it also trips the counter!
So we now have cash or tokens, and 6d, 1s and 2s play. Just the coin-entry labels to recreate, and another historic machine is free from the stain of decimalisation.
I'm now awaiting delivery of an ACE 'Double Chance'.
Anybody heard of it?