Number one cylinder no spark

As non of the Gurus have responded to you, I will do my lowly best.

Starting at the spark plug end;

Defective plug - it seems you have tested for this and found the plug(s) to be A1

Defective cap- can be caused by manufacture/assembly defect, overly rough removal causing damage, poor seating. Continuity failure - check using multi meter - be sure to wiggly & twist the cap (simulating engine vibration,torque movements & air blast) as you check.

Defective HT Lead - can be caused by manufacture/assembly defect, using lead to remove cap causing damage.Continuity failure - check using multi meter - be sure to wiggly & twist the cable as you check.

Modules (Black box)- sorry no wisdom here - They are a capacitor discharge set up. Sealed no repair possible.

If Module delivering spark on other plug  , I would assume that the rest of the system - charge, ignition trigger (fly wheel housing) wiring harness and connections all good.

Refer to Heavy Maintenance Manual Section 74-00-00 for more/better insight.

"Trigger coil assignation (on the 912 Series)

Trigger coil A1/2 serves the top spark plug of cylinder 1 and 2

Trigger coil A3/4 serves the bottom spark plug of cylinder 3 and 4.

Trigger coil B1/2 serves the bottom spark plug of cylinder 1 and 2

Trigger coil B3/4 serves the top spark plug of cylinder 3 and 4."

I'm guessing a damaged cap.

Found problem from last year, trigger coil gapped at 60 thousands,  the one at 7 o'clock position as I recall, all good now

    2/14/24 just posted a really different problem - under dunnboys , variable cylinders not firing

Any help appreciated