the middle switch on the handle release relay isn't the only switch in the circuit. If you want, just jumper the 90 wire to the 63-3 wire and see what happens.
wire 63-3 comes from the coin replay on the left side of the reel unit, so also looks at 63-3 and 60-1 on that relay.
63-3 is a brown/yellow wire and 60-1 is solid brown. Looks like in your pic on post 20 those wires are on the two blades furthest from the coil
your payout counter in post 33 is reset, so it should look like that whenever you didn't have a win...the position of the spiral and the switch being lifted open.
if you have an meter that measures resistance or a continuity tester, you can with game power off:
0] set up any winner on the reels
1] pull out the reel mech
2] manually trip the coin relay or stick paper between the contacts so 60-1 is not connected to 63-3
3] clip a meter probe to wire 63-3
4] push the reel mech back in
5] pull out hopper and connect other meter probe to grey/yellow wire 93 on the payout relay coil.
6] push hopper back in
you should get almost zero ohms on the meter. If you don't, move the probe from wire 63-3 on the coin switch to 63-3 on the handle release coil. If still nothing, move the probe to wire 90 on the handle release coil.
what you are doing
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if you look at the schematic around H10, wire 63-3 comes from the coin relay switch and thru the handle release switch onto wire 90, and from there the circuit goes into the reel wiper boards. If the reels stop at positions that are winners, wire 90 connects to the appropriate numbered trace on the payout disc, and from there the circuit follows wire 93 to power the payout relay.
when the payout relay powers, the hopper turns on. On your machine, as each coin is ejected the payout counter mechanically steps up and rotates the payout wipers. When the payout wipers step off the end of the payout trace associated with the winner, the payout relay loses power, the hopper is turned off, and payout is done.
the ideal way to probe the circuit is game power on and an unpaid winner on the reels. Put one meter probe on wire 70 on any handy 50V coil, use the other probe anywhere along the circuit path from wire 63-3 to 93 and look for where the 50V drops significantly or disappears.
the hard part is getting the probe onto the places you want to check. Without extension cables to run the reels or hopper outside the cabinet, you have to keep pulling out units, clipping on the probe, and pushing them back in without shorting the probe to anything.
on your game, you can turn the power off, place the probes, and turn it back on to have it keep doing what is was doing.