[volt-nuts] Junior Member Lost Shirt on 720a KVM Purchase

Stan Katz stan.katz.hk at gmail.com
Tue Mar 24 22:32:54 EDT 2015

I purchased a 720a KVM off Ebay, and let it sit until I had gotten my
HP419A Null Meter working.  I now have the null meter working, but it
appears that the 720a sealed switch S1 ("A" divider ) is bad. At least
that's what I think. The "A" divider dial has no effect at any dial
position (constant open "A" divider), and only the B - G switches work.
Rotation of the entire instrument to a vertical position causes the "A"
switch to lock up between positions 4 and 6. Thus, my guess is something
broke off inside the switch and just happens to settle into a
non-interference location when the instrument is righted.  The switch was
manufactured for Fluke by Tech Laboratories of Palisades Park, NJ and bears
the stamps 720A-801 Rev2---2012-1512-3. That firm seems to have gone out of
business sometime in the 1970s. I did a proforma check of solder joints to
see if I could spot any cold, or open ones. They all looked good to me.

Does anyone have any advise as to my next action with the instrument other
than resell this one on Ebay for "Parts not Working" and taking a chance
with another Ebay purchase?


More information about the volt-nuts mailing list