Well, how simple can it be...
Tacho dead = probably capacitors.
Removed the cluster, swapped capacitors and noted that the tacho still did not work.
Looked at the internet: perhaps stepper in gauge died, maybe.
So, checked for an replacement tacho. But it must be an 9.000 rpm tacho with 'economy' leds.
Most tacho's over here are 8.000 rpm tacho's.
Finally found one, coming from an ST182, I suppose, it is having an volt gauge. Swapped tacho's, still dead.
Hmm, both broken???
Seller shipped two clusters, one with 9.000 and one with 8.000 tacho.
Swapped with the 8.000 rpm tacho, also dead.... huh??
Okay, took the multi-meter, checked continuity from igniter to tacho connector: no signal!!
Followed wiring and somewhere near the Autronic ECU, there was an 1K ohm resistor that was going to maximum resistor!!! Bummer.
Cut the resistor, connected wires and ready. Man o man, that was my price for taking the lazy route instead off checking wires with the multi-meter. *sigh* always I check wiring with multi-meter, but once...... :crazy:
Anyway, let's take it to the positive side: my tacho is already having fresh capacitors now
BTW, the resistor was there, since back in the days off installing this Autronic in 2000, they told me to add an 1 K resistor to the tacho signal, no idea why? The stock tacho is already having an 43K ohm resistor added, so no need for this one.
https://www.gtfour.nl/celi014old.htm