you were good up thru 2:10 into the video ... except you weren't looking at J.
at 2:31 into the video just after it scored the second time, the bonus unit stepped correctly, then almost immediately stepped again. That second step is wrong and is what is causing you to miss bonus points. I assume the second step happened when 1A closed ... the stack is just barely not visible in the video when you panned back to the motor.
guess who gets to make another video? ... or at least check something
do the whole process again and note when the J relay is powering and unpowering.
what you really want to do is:
1] manually turn the cam the first time and verify nothing happens in the first cycle (120 degree rotation) until near the end when I powers
2] turn into the second cycle past the scoring/chime and stop immediately after the bonus unit steps (coil unpowers).
there's a timing overlap at this point that may be sensitive to switch adjust, so one of the following should be true
[A] I is powered and J in not powered
[B] I is not powered and J is powered
in either case, motor 1A must be open still (1A stack not lifting on the cam tooth).
if the state is [A], turn the cams very slowly and make sure it changes to [B]. You must be in state [B] before 1A closes or you will get a second bonus unit step and lost bonus scoring.
I'd watch motor 1A and if the stack starts to move after the bonus unit steps, stop!
[X] If J is not powered, you need to find out why.
[Y] if J is powered, keep turning the cams. If the bonus unit steps when 1A closes, then you have a J relay switch that isn't working right.
since your problem is intermittent, you will likely need to manually turn the cams multiple times until [X] or [Y] happens.
the ideal thing is [X] ... you leave the score motor stopped at the position when J should be powered and examine the below circuit. Just to emphasize, I should be unpowered at this time.
bs-j relay (resized).png
I just use a voltmeter ... one probe on the wire on the BLK-WH on the J relay coil, the other poking along the highlighted path until you find where the 6VAC drops/disappears.
note the wire colors on the J relay coil are BLK-WH and MAR-WH. If you can't tell the difference, put a meter probe on the a 6V fuse (either end of either one) and poke the J relay coil lugs with the other probe when the J relay is powered. When you see 6V, that's the BLK-WH wire.
if [X] is the issue and the meter doesn't find the problem (or you don't have one), then you'll need to use a jumper wire. You could leave the score motor connected, but before closing the outhole switch jumper the C, O and I relay switches one at a time and see if that makes a difference. e.g.
jumper YEL to GR+WH on the C relay and close the outhole. If it reliably scores the bonus, that's the problem switch. If still flaky, repeat but jumper GR+WH to SL+WH on the O relay, etc.
the upper circles in the bonus unit box on the schem are all connected like the #15 path shows since all the targets are down. To eliminate the bonus unit wipers as a problem, you'd jumper YEL to BR-BLK on the bonus unit and as long as 15 target is down, you should score 15K.
if you aren't sure of the switch adjust, try and take a video of the sides of the switches on the I/J/C relays with the game power off and manually operating the armature plate. Need to see the behavior of the armature and the contacts. If you can't get to the I or J or C relay easily with the camera, do it on any relay that's easy to see. The key things are the armature lifting all the way, the overtravel of the blades after contacts touch and the switch gaps on open switches.