Re: Tacho problem

["David Kirk" <david@domain.elided>]

Dear Paul,

I to have ongoing problems with my Tacho so I would be interested in sharing
my knowledge gained so far in the event we have similar problems.

First, have a look at the Luminition page on FAQ's reffered to only recently
in the digest. It is at http://www.denaploy.co.uk/autocar/faq.html

It not only has a few suggestions for problems with Tachos used with their
ignition system, but also a very good technical description of the different
Tacho technologies around.

I have an RCI type fitted, which is current sensing. My unit works only
intermittantly and after pulling the thing apart and in circuit testing all
the components all looks well, but it still functions part time. I am
convinced that the problem is related to the bounce on the points or
performance of the condenser or type of HT coil being used. I still havn't
got around replacing these which will form part of my next service job and
if my theory is correct, it will solve the problem.

It sounds like you may have an RVC type (Voltage sensing). I know even less
about this type so no help there but I do run an electronics company and it
may be that I can trawl through some IC finders for equivilents if you let
me know the exact markings on the IC and the type of package (how many legs
etc.)

Regards
Dave Kirk

-----Original Message-----
From: tashtris <tashtris@domain.elided>
To: stag-digest@domain.elided <stag-digest@domain.elided>
Date: 18 April 1998 05:18
Subject: Tacho problem


>Has anyone got an idea of how to fix a dud tacho.  As there are very few
>components ie an IC and 4 capacitors, i presume that it is an IC
>problem.  Unfortunately Texas Instuments, who originally manufactured
>the IC, have no idea about any equivalents etc.  Does anyone have any
>ideas on the replacement IC ?
>
>Paul Dean
>
>