Concept2 DYNO PM2 doesn't count.

[TSUM]

I have a model C with PM2 that no longer counts.

I had the battery leakage issue but managed to restore all functionality for a short while. initially the count function worked, went intermittent and then stopped completely. The rest of the display functionality is fine.

The sensor wire measures 104 Ohms and the resistance changes up and down if I rotate the fan. With the fan removed I can trigger the PM2 to switch on by "flicking" a magnet very near to the sensor. All display functionality apart from counting is present.
I've checked the magnets in the fan, they are in good condition. I've ensured the fan bolt is tight.

I'm speculating that there is a sensitivity issue somewhere. I'm assuming the sensor and its wire is fine .......so the monitor counting circuity is suspect?
As the count function did work initally after repair perhaps there is poor connection somewhere?

The sensor wire socket on the board appears to be in pristine condition as is the circuitry in the area around the socket. I've not removed the LCD to check underneath ....however I'm sure there is no corrosion.

Any suggestions of voltages or other things to check would be much appreciated.

thanks Tim