there's two ways for the tilt light to come on"
1] the tilt trip relay trips
2] the anti-cheat relay loses power
usually you have this problem when a high-current coil needs to be powered (the ones with plungers), there's something wrong in the circuit that causes the 50V supply to droop down and the anti-cheat relay loses power.
first check is to see if there's a mechanical issue. Manually step-up/reset the replay register and make sure the number wheels turn easily.
the payout sequence is a little different for inline scoring vs. section scoring, but the first step is to figure out how far you get. Easiest when done from the back:
1] reset game and leave screen in home position.
2] shoot four balls and place in playfield holes so no winner is created, but placing a 5th ball will create one.
3] push the R-button and verify the search wipers release and the search relays chatter. With no win, nothing else should happen and the search wipers will eventually lock back in the home position
4] shoot and place the 5th ball to create a 3-in-line or more win
5] put paper/business card between the contacts of search index switch 19B. That will prevent the replay cams index coil from powering
6] from the back, manually push down the search wiper lock magnet armature to release the search wipers. Make sure paper stays in the switch.
7] when the wipers reach the right position for the win detect, the search index coil should power and stop the wipers
8] pull out the paper and see if the anti-cheat lets go when the replay cams index coil powers or shortly after when the replay register tries to step up.
if it seems the problem is when CU cam 13B closes to step up stuff (you can put paper in that too the verify it's not the replay cams index coil), first check to make sure wire 48-4 going to the ball trough area isn't shorting to something. It usually went to a replays meter which shouldn't be active when the coin/back doors are open, but operators often permanently closed those switches. If the meter is bad or mis-wired, you'd be in trouble.
if meter wire is ok or the door switches are open, i'd just bite the bullet and disconnect the 48-4 wire from the replay register step-up coil. Jumper wire 30 to the coil lug and see if the register steps ok. If it does, jumper wire 30 to wire 48-4 and see if the reflex unit step-up coil powers ok.