Beta 25 alternator, output failure[s]

[Straightman21]

The tacho failed on my Beta 25. Some research showed that it is powered via the 40 amp, 3 pin battery sensing alternator outputting circa 8v AC to drive it. Checked output but no volts. Had it tested, agreed no output. Bought new, same issue [I also took a lead directly from the back of the tacho to my multimeter to ensure that it was a tacho problem rather than wiring etc. Also, both alternators are only putting out around 12.67v rather than the 13+ I would expect. Any ideas / thoughts would be welcome.

 

[Boater Sam]

The tacho failed on my Beta 25. Some research showed that it is powered via the 40 amp, 3 pin battery sensing alternator outputting circa 8v AC to drive it. Checked output but no volts. Had it tested, agreed no output. Bought new, same issue [I also took a lead directly from the back of the tacho to my multimeter to ensure that it was a tacho problem rather than wiring etc. Also, both alternators are only putting out around 12.67v rather than the 13+ I would expect. Any ideas / thoughts would be welcome.

A short circuit on the W tacho line?
Loom multiplug problems?
Beta panel tachos are known to die.

 

[DanTribe]

I gave up trying to understand electronics some years ago when the right hand side lights on my Alfa always stayed on.
Garage straight away said "rev counter problem."
"Are you winding me up!?"
"No, honest, known problem"
He was right, new tacho, all kushti.