By way of today’s progress for those who might find it helpful....
I discovered that the main bank of cam switches had been knocked backwards one one side, meaning switch 1 wasn’t operating. There are a couple of adjustment screws for this, so that was out right, and the contacts for switch 1 also needed bending slightly. This got the microswitch on the coin op working and the machine now makes one cycle before switching off again. The coin mech will need a complete strip down I think, so I still need to check the rest of it.
The brake on the middle reel was still not releasing. I checked the voltage on the solenoid which did indeed appear at a point in the cycle. I then discover an open circuit on the solenoid coil. This filled me with dread, as I thought a rewind would be the only option. I first had to remove the metal chassis that the 3 solenoids are mounted on. I then drilled the rivets on the solenoid and removed the solenoid from the unit. I managed to remove the switches and actuator from the coil. I carefully removed the paper covering from the coil and was about to start unwinding the coil from the core when I spotted a tiny break in the coil just before it entered the end terminator. A quick touch with the soldering iron and it was back to 800 ohms on the coil like the other two. Re assembled and replaced, confident that this will get the middle wheel turning.
Plugged in to check my work and a quick spark and blew 2 fuses! Then realised that in removing and replacing the bank of solenoids I must have knocked the switch mounted on the cam on the front of the motor, shorting some of the tabs where the wires are soldered on to them! I soon bent these back but now have to wait for some replacement fuses.
While I’m waiting for those to arrive I might attempt the coin mech..... I’ve also removed the ‘extra’ payout unit for the time being.
Hope this is helpful to someone sometime. Will be back with the next update!