John;

I question your statement of the 140 instruments being more reliable...I'll grant you, the filled thermal system (capillary) tube temp gauge on my 122 is mechanically more fragile, but these are perfectly adequite, and don't require ANY electrical power to operate - except for the lamp lighting up the guage!....mine have yet to fail, whereas I'd be willing to bet MOST original "Voltage Stabilizers" have died a miserable, electrically violent death long ago (taking gawd knows how many of the instruments with them as well!). I wonder what FMEA (Failure Modes, Effect Analysis) engineer signed of (if any) on that marvel of electrical engineering? [NOT!!] BTW...Was that thing made by Lucas?

Vo;

It really isn't that complicated...its just a heated bimetal cycling contact whose LONG-TERM-AVERAGE is 10V. It's output is continually cyling between 12 and 0V...and that's the reason it starts of at 12V...the heating element has just been energized and so has not yet caused the contact to open. This module is located behind the big instruments (held in place by the same thumbscrew which holds on either tach or speedo...don't recall which). John is right...if they fail in the contact closed mode (12V out), your instruments are doomed! I recommend you loose it, and replace it with a solid state replacement available from ipd.

...more info on this subject at: http://www.intelab.com/swem/service%20notes.htm#Electrical

Cheers