[POKDUB]

I have just repaired my RPM transducer over the weekend. Simple fix.

The spade connectors had become loose from the pcb. This was very hard to see. The solder joints had broken on the underside (reverse of your two pics). Have a look again, wiggle the connections, see if there is any breaks in the solder connections.

If so, you should heat solder, and if possible use a solder vacum pump to suck off old stuff. Emery paper the connector points and resolder.

On another point, I dont think the RPM Transducer is really an aid to tuning, it is really geared towards fuel cutoff. The popping / backfiring needs to be cured elsewhere (IMO).

Rgds
Peter