the open-at-top switch on the selection feature unit is on the ratchet side of the unit. Switch pokes out over the white ratchet and a pin opens the switch at the top stop.
usual hack is to misadjust the switch so it opens 1+ steps too early, tho it's odd they would want to disable card 6, so maybe just an adjust error someone made.
the coin unit is irrelevant. It just controlled where the inserted coins went - either the main cash box or the side cash box. The idea was the location would have the key to the side box so they could recycle coins. The coin unit was adjustable to deflect anything from 1/2 to 1/6 of the coins using a jumper.
I think the only thing the timer unit did on that game was turn off the CU motor at the top step. Since pushing the R button caused the 1-2-3 search cam switch to close and turn the motor on, turning off the motor sooner reduces wear-n-tear and noise.
watch out for the "made only when energized" score index switches 15A and 16A. When the index arm riding on the cam edge, those must be open or the payout will round up to a multiple of X, where X is probably 16 on that game. The switches should only be closed when the index coil is powered and the index arm is lifted off the cam edge. If the switches never close, you'll tend to burn pits in the traces on the score counters.
if ya want to email lots of highest possible resolution pictures of the game internals to [email protected], that'd be great. The pics I have are too low a res to see a lot of details. Entire back door, entire inside of head and closer shots of whatever ya like are useful, especially when zooming in lets ya read labels and see wire colors.