is ya want to email highest possible resolution pics to slotpics@cdyn.com, that'll help ... especially the inside of the door.
you have a 1089 model/serial number plate on a 1090 (3 coin multiplier) triple bar style game. Most likely the 1089 was converted.
most 1089 machines were $1 games, so they had a coin scavenger circuit. If the machine was made for or converted to 25c play, they changed from coin scavenger to coin lockout as david described.
the gotcha is the circuit is inverted. A coin lockout circuit powers the coil behind the coin mech when the game is ready to accept a coin. A coin scavenger circuit powers a solenoid mounted on the side of the coin mech frame when it wants to reject a coin.
in your posted door pic, it looks like you have an added relay on the door with some wires going to the mech area. If so, that relay is probably inverting the circuit and they changed the scavenger to a lockout coil. When that relay is unpowered, the coin lockout coin should be powered.
the 1090-7 schematic shows how the above was implemented. You can find that on
https://bingo.cdyn.com/slots/for triple bar, the 1090-34 schematic will be similar ... but you have cherry pays and it doesn't have cherries. There's codes stamped into the slotted metal index discs on the reels ... can you see what the one on reel 1 is?
wrt payout, first thing to verify is the payout counter is resetting. The payout counter is in the bottom/right/rear of the cabinet and you need to pull out the hopper to see it. The main wipers with a span of 6+ fingers should be at the bottom when the unit is reset.
if the payout counter is reset, you can use a voltmeter or jumper wire to find the issue. Got either/both of those?
the general idea is when you have a winner, you should have a closed circuit from grey wire 90 on reel #3 wiper board to the appropriate wire on reel 1. e.g. for a single cherry win, if you stick ohmeter problems on grey wire 90 and red/white wire 15 on reel 1, you should see almost zero ohms. If you get that, the issue is likely not on the reel wipers ... and unless it's a plug connection issue, probably not on the reel mech at all.