(please read first through the whole post)
the Double-Bonus problem has to do with "delicate timing". A wild theory is: The "Self-Hold-Switch on the L-1000-Point-Relay" does not work so the L-Relay let go a bit earlyer than it is supposed to. I hope the "Self-Hold-Switch on the M-10-Point-Relay" is good. You have all over the playfield on the sides some leaf switches behind rubbers. TRY: Manually make some 10 points --- sometimes a "bulls-eye, full impact hit" --- sometimes just a "grace shot (You close the leaf switch just for a VERY short period of time)" - You should ALWAYS get the 10 points onto the Score-Drum. Now, see here http://www.ipdb.org/showpic.pl?id=2500&picno=23190 --- the inlanes are worth 1000 points - question: Do You ALWAYS get 1000 points - no matter "full impact depressing" or "grace-shot like (manually closing the switch for a VERY short period of time)" ?
IF (if, if) You do NOT get the 1000 points on "grace shot": We must look at the "Self-Hold-Switch on L-1000-Poin-Relay".
OK, the "test / theory written above" most likely is not true as You ALWAYS get the 1000 points (?) by manually pressing the Inlane-Switches - but the situation is "close to desperate" - we look all-over ...
I made two JPGs using "woz timing chart / snippets of schematics". The first is "Single Bonus" - nice, synchronous stepping / pulsing the L-1000-Point-Relay and the TA-Bonus-Unit.
In the second JPG the stepping "encircled orange" of the TA-Bonus-Unit is much slower because SCM-2D and SCM-3B are involved - they let shots of electricity fired by SCM-4A pass to the Coil on TA-Bonus-Unit --- AND WHEN SCM-2D / SCM-3B ARE NOT ACTIVE: The shots fired by SCM-4A CANNOT pass (they are "masking Switches").
Maybe, maybe in Your pin the SCM-2D is faulty NOT closing so the TA-Unit gets the two times two-thousand points a target.
Maybe, maybe in Your pin the SCM-3B is faulty NOT closing so the TA-Unit gets the two times two-thousand points a target.
Because towards the L-1000-Point-Relay: The firing works through SCM-4A pulsing.
So I would like to test with ONLY ONE target dropped: The "encircled green '0' , Zero". EVERY drop target when dropped has a switch closed - wire-color-red-white and wire of "other color".
That "encircled green '0' , Zero" switch has wire-color-red-white and wire-color-yellow. The switch next to it in the schematics has wire-color-red-white and wire-color-black-white.
Please look-up in Your pin - so You can say "10 drop targets on the top of the playfield, left to right are the switches in the schematics --- well the number, the number, the number ? --- also the 5 drops on the lower playfield are ... ?
I still have problems of understanding --- see my "dark-blue question mark" - I do not understand how a fully running pin wired as shown in the schematics can work --- If I would have to wire the Target Alpha: I would have put in "masking switches SCM-1B and SCM-4C to hinder the "shot of electricity fired by SCM-4A (my encircled dark-blue stuff).
May want to have another look at SCM-2D and SCM-3B - do they TRUELY close ? Wires soldered-on ? Greetings Rolf