Beta 25 rev counter failure

[rumtoddy1]

Good morning all

I have a beta 25 in my boat and the electronic rev counter has stopped working. As the rev counter receives a signal from the alternator I have checked all the wiring and this seems ok. I have assumed that the rev counter is functional as the needle twitches when switching the ignition on but displays no revs on start up. Investigation suggests that the sender in the alternator has failed but I have no idea if this is a serviceable item or if the only solution is a new alternator.

Any advice or previous experiences gratefully received. The boat is based in tha harwich harbour area.

Clive

 

[andsarkit]

Alternator based rev counters just have a connection to one of the diode bridges inside the alternator. If the alternator is working then the signal should be available.
Can you check with a multimeter to see if there is an AC signal on the wire?
Is there a fuse in the wire that is not connecting well?
Check all the wiring with a meter and not just visually.

 

[sailorman]

Is the alternator belt slipping
When i installed my Nanni i had to tell the rev counter what alternator was fitted. Its 18 yrs ago so cant remember what i had to do to programme it.
Migh be worth checking yours is correctly set

 

[earlybird]

The tacho signal is the black/blue wire from the "W" terminal on alternator. It should show approx. 9v. AC when the engine is running.
Are your panel alarms etc. working? (It sounds as if they're OK if the tacho flicks on switching on).

 

[PetiteFleur]

I had a similar problem about 3 yrs ago on my Beta 25 when the hourmeter display gradually faded until it could only be read in certain light & direction, so I fitted an electro mechanical meter in the engine compartment triggered when the engine was started. With a label saying how many hours to add to the display for accuracy. The rev counter still works ok though.

 

[VicS]

There is no "sender" in the alternator. As said the tacho connection is an AC output direct from one of the windings
If the alternator is working then there is unlikely to be any problem with the "signal" output for the tacho

As suggested check for an output from the tacho connection . "W" terminal or black/ blue tracer wire

If output found check again at the input to the tacho

( also double check that you really do have power to the tacho)

Suspect either the the tacho itself or a bad connection in the wiring harness

( in any case never just replace a suspect alternator ... Always get it checked and repaired by an auto electrician at a fraction of the cost

 

[Boater Sam]

Nasty wiring loom plug/s not making proper contact? Got 12v power to tacho head? Else its likely a duff tacho.