When the machine came out of the shed it was fully working. After the first win 3 cherries it paid 20p (2x5pp + 1 x10p), but before the win timer could return to it's start position the cam on switch 13 partially slipped off the switch (CS13).

 

Although the grey cam was still in line with the switch, crucially the red cam was not. The result of this was that the payout timer was not at 0 degrees so when the next win occurred the cam was in the wrong start position and the win did not pay. (Cam position is crucial on an electro)

 

I stripped and cleaned the reels possibly bending the wiper on reel 1 which meant no wiper contact with the win studs. This was corrected later but still the wins were not restored.

 

Eventually the cam issue was discovered. I levered the cam back onto the switch, but 2 wires pulled off the win timer, one of which was incorrectly replaced. At this point the machine should have been fixed, but the incorrect wire on CS20 meant that the 50p wins were paid as 10p.

 

Years of making mistakes have taught me to photograph any complex assembly before taking it apart. I went back to my pictures. I noticed that the spade on CS20 was on the wrong terminal.

 

Many thanks to Ron for all the help with the repair.