winner light on and game not paying is probably the payout counter not resetting. May also want to check the horizontal switch in front of the payout counter spiral cam to make sure it's clean and closing when the payout counter is not reset. A jumper wire to short the switch closed can be used to check it.
coin lockout coil not working could be a dirty/misadjusted switch or a plug connection. Quick hack is to remove the coin mech and put a piece of tape on the back so the lockout armature tab can't poke into the mech after the mech is reinstalled.
both problems could go away if you remove/reinstall the reel mech and hopper a few times. If ya want to be more thorough, remove the hopper and reel mechs and scrub off the plug pins with a wire brush, synthetic steel wool, metal cleaning pad, etc. to remove any surface oxidation. Cleaning in the sockets is harder without the right shaped tools so don't bother unless there's obvious a lot of crud in them that doesn't scrape off after a few insert/remove cycles.