Rev counter issues

[Chris_Robb]

I have a non working rev counter (Volvo 2003T) - it occaisionaly registers but rarely. When I changed my alternator to a 110 amp prestolite, the revs were wrong as the pully was larger. I was told that you could adjust the Revcounter - but I could never see how. The lack of a rev counter does not bother me as I can hear exactly what note the engine shoulf be at 2500 revs - but it still remains that it is on my maintenace log and has been for 4 years!!!
How do I check which is the culprit - the W lead from the alternator or the rev counter itself? - I have done the obvious and cleaned the connections.

Any Ideas?

 

[rogerthebodger]

The rev counter will probably be based on a VDO but labbles Volvo.

Can you post a pic of the back side of the tacho

 

[Chris_Robb]

The rev counter will probably be based on a VDO but labbles Volvo.

Can you post a pic of the back side of the tacho

I took some photos---- cant find the buggers!
Its 1991 vintage yacht and it has no engine hour meter if that helps.

To test with a multimeter, what should I expect out of the W terminal (rev counter sensor). Hopefully we will go to the boat in Greece in September - then I can take some new photos.
I was hoping if I replace with a VDO all the cables will fit!

 

[earlybird]

[QUOTE
To test with a multimeter, what should I expect out of the W terminal (rev counter sensor).
[/QUOTE]
The W output will be ac. DVM reading probably in the range 8-12 v. assuming a 12v. alternator. The tacho measures output frequency.

 

[Rappey]

was told that you could adjust the Revcounter -

Some have a small screwdriver slot in the back, usually with some markings.
Mine had a warning to be very gentle as it's really easy to accidently push the adjuster inside and therefore have no adjustment at all.
Yes it is ?

 

[rogerthebodger]

There are a number of alternator driven tacho details here

vdo alternator driven tachometer dip switch settings - Google Search