Re: Warm up time on old capacitor checker

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: Mddeming-at-aol-dot-com 

In a message dated 12/20/03 10:39:28 AM Eastern Standard Time, 
tesla-at-pupman-dot-com writes:

This is directed to a few of the old timers out there.  I have an old
hamfest Heathkit capacitor checker, and was doing some MMC readings last
night.  It didn't even want to register anything on the green eye until it
warmed up for at least ten minutes!  Is this normal for these things?  I'm
used to new stuff, where results are instantaneous in this solid state age.
Each of my 942 series caps measured out at .15 on this old thing, and a
string of 7 measured about .02, even though it should be about .0143.  Do
you think that this is accurate, or is my "Ten Minutes to Warm Up Heathkit"
off a little bit?  I'm not disappointed if it is, as it was only fifty
cents.

Hi John,
     Most vacuum tube based equipment requires warm-up time. It also 
requires temperature stability, meaning a sudden. drastic change in 
environmental temperature can throw it off until it reaches equilibrium 
again. Tubes also age with time and older ones may not be up to specs. 
might consider tube replacement. Since .15/7=0.0214 at least it's 
self-consistant. Are you sure they aren't 0.15 caps? Try measuring several 
other caps of known value from which you can plot a calibration curve to 
use as a reference.

Matt D. (in the 60th year)