Topica Loopframe_Guzzi Archive


Subject: Tachometer Info needed

Author: murp-@aol.com

Date: May 9, 2001, 11:12 PM

Post ID: 1706660308


A few days ago I posted to the list a description of how the
Ambo/Eldo electronic tach could be used with a 2-coil (no distributor)
ignition system. In order to figure out the required circuit (which was
just 2 diodes and a resistor), I needed to get an estimate of the input
impedance of the tach.
I have a problem in that when I bought my bike for restoration, the
tach did not work, and I never tried to fix it before I took the bike
apart. So, I did not know if the tach was not working, or just not
connected properly. I took a look at it yesterday, and tried to measure
its DC resistance using a multimeter, which measured an open circuit. I
don't know if a working tach should have an open circuit (I was
expecting some high resistance value), indicating that it is
capacitively coupled, or not.
I am wondering if someone out there with a working tach could help
out by measuring the DC resistance across the + and - connections on the
back of the tach.
Also, I tried to get inside the tach, but had no success. I
unscrewed everything in the back so that the movement inside was loose,
but could find no way to get off the chrome bezel. Has anyone ever done
this?
Any help would be appreciated.
Brian Murphy
'74 Eldo
'78 T3

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