On Friday, February 2, 2018 at 9:55:03 PM UTC-5, Phil Allison wrote:
John Robertson wrote:
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** The Bob Parker ESR meter has an auto-ranging, two digit display that over flows above 99 ohms. It shows ESR values from 0.01 ohms to 99 ohms. The black button zeros the reading before measurements and also cycles the meter on and off.

http://i44.photobucket.com/albums/f9...SCF0045-86.jpg

The "good" 22uF, 500V electros showed readings close to 1.5 ohms while the "bad" ones were completely open. In reality, 2 of the 3 "good" electros were just about to fail open circuit.

Electro caps normally dry out and go high ESR fairly slowly, ones that test perfect one day and go DEAD the next are not playing fair.



I use (and sell) Bob's ESR meter kit (over 600 sold since 1999). The
only improvement I can suggest is to use a regular fixed range digital
ohm-meter in parallel with the leads to be sure the low reading isn't
actually a shorted component.


** Yes, a rare dead short in a capacitor hides its ESR from any meter PLUS caps wired in parallel have a "team ESR" that can hide bad member.


Years ago I bought a portable ESR tester for my truck for working on PTVs and arcade monitors on site: http://www.drviragopete.com/resources/Eds88Aom.pdf

This meter will pick up a shorted cap or shunt circuit and display it as low DC resistance and not ESR.