[AMRadio] Test equipment - Heathkit capacitor tester

Rob Atkinson ranchorobbo at gmail.com
Sun Nov 19 18:22:24 EST 2017

There's a cruder way to check for leakage that's more of a pass/fail
method.  with clip leads and a knife switch and VOM spread out on a
bench run a clip lead from the + lug on the capacitor tester variable
DC supply to one side of the spst knife switch and another clip lead
from the other side of the switch to one lug of the cap under test.
The free lug on the cap goes to the + terminal of the VOM set to
measure next voltage scale above the maximum positive DC supply
voltage and the minus lug on the VOM returns to the minus lug on the
variable dc supply with a last clip lead.  with knife switch open run
the voltage up to near the maximum rating of the capacitor and drop
the switch blade.  The VOM should swing up to whatever that voltage
is, and as the cap charges, drop down.  If there's no leakage it
should get to zero volts eventually.   With leaky old oil caps it will
drop down to around 10 or 20 volts and hang there.
For comparison try the same test with a modern new 1 mfd polypropylene
600 v. cap.  VOM will quickly swing down to zero.

>  I like to not replace electrolytics until I get the
> equipment
>> running and see where I stand.

One of the first things I do is cut out and toss out old paper wrapped
and wax sealed electrolytics and replace them with new.   I don't give
them a chance to destroy a transformer by trying to get the equipment
running with them in there.



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This page last updated 17 Jan 2018.