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Re: How to test a condenser

To: "Barney Gaylord" <>, <mgs@Autox.Team.Net>
Subject: Re: How to test a condenser
From: "Harlan Jillson" <>
Date: Thu, 10 Dec 1998 05:24:22 -0600
   The real way to check it is with a capacitance meter, which will usually
tell you the capacitance at 1 K hertz, and maybe at a higher frequency.  You
can do a check with an ohmmeter to tell if its totally caput or not.
Measure the resistance of the condenser with the ohmmeter ( wait for a
steady reading..), this will charge the condenser up to the voltage of the
source being used to check the resistance in the meter.  Then reverse the
leads and check it again.  What should happen it its not total zapped
 technical term) is the resistance should read initially real low, then
creep up to the previous reading.  This is caused by the condenser
discharging through the meter then building up to the voltage in the
opposite polarity.  It doesn't tell you much about what the capacitance is,
but give and indication that it's doing something right.
   One caveat,  this test works better with the old fashioned analog meter
because its easy to see the needle swing.  The digitals tend to be harder to
see because of the sampling rate of the meter when taking a reading.

-----Original Message-----
From: Barney Gaylord <>
To: <>
Date: Wednesday, December 09, 1998 9:37 PM
Subject: How to test a condenser

>Oh ye, wisdom of the list,
>A new experience every day, and now for the first time in my life I finally
>had a condenser fail on me.  The last one lasted several years and 100,000
>miles without a problem, and I only changed it out of superstition, or
>maybe as a point of preventive maintainance.  Now after only several
>thousand miles in six months the new one has failed miserably.
>I checked everything else in the ignition system, cleaned and/or replaced
>the points, rotor, dizzy cap and pug wires, and even tried a different
>coil, and the car still ran like crap, would hardly move under its own
>power.  It should have been a clue when I disconnected the condenser wire
>and it didn't make any difference at all.  After weeding through all other
>possible causes, finally in desparation I removed the new condenser and put
>the old one back on.  Now it runs like a MG again, cranks right up past the
>red line without missing a beat.
>Now as something I have asked before but never gotten an answer, aside from
>not being a dead short circuit, how do you test one of these little
>critters?  I think it would be nice to be able to tell good from bad and
>not end up with a dud in my spare parts bin again.  Anyone have a real
>answer?  Maybe some educated electrical tech guru on the list?  Physics 102
>was way too many years ago, and I really don't feel like making a trip to
>the library if someone on the list can answer this one.
>Thanks in advance,
>Barney Gaylord
>1958 MGA with an attitude

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