As of this moment it has run over 26 hours without shutting down. I've
never seen any evidence that ESR can be an intermittent phenomena. Can
someone please tell me how intermittent ESR comes about?

--

73
Hank WD5JFR
wrote in message
oups.com...
Henry Kolesnik wrote:
snipped:
At this point I'm not willing to do a
shotgun replacement of all the caps. I do keep running the power
supply and
the condition is not getting worse. I wish it would fail so I might
find
the failed component. The way it is now it's impossible to
troubleshoot
without shotgunning.




Henry:
Looking for cracked circuit board connections AND testing the
electrolytics with an ESR meter (or substituting electrolytics if you
do not have an ESR meter) is NOT "shotgunning".... it is real
troubleshooting advice as a result of the symptoms you posted. If you
continue to use it with the problem you reported it may fail completely
and be a bigger repair job.
Pay a little now Or pay a lot later.
electricitym

You should at least test the electrolytic caps in the startup circuit.

Since as I recall, it blows up only when applying AC power suddenly, something
funny is going on during startup.

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"Henry Kolesnik" writes:

As of this moment it has run over 26 hours without shutting down. I've
never seen any evidence that ESR can be an intermittent phenomena. Can
someone please tell me how intermittent ESR comes about?

--

73
Hank WD5JFR
wrote in message
oups.com...
Henry Kolesnik wrote:
snipped:
At this point I'm not willing to do a
shotgun replacement of all the caps. I do keep running the power
supply and
the condition is not getting worse. I wish it would fail so I might
find
the failed component. The way it is now it's impossible to
troubleshoot
without shotgunning.




Henry:
Looking for cracked circuit board connections AND testing the
electrolytics with an ESR meter (or substituting electrolytics if you
do not have an ESR meter) is NOT "shotgunning".... it is real
troubleshooting advice as a result of the symptoms you posted. If you
continue to use it with the problem you reported it may fail completely
and be a bigger repair job.
Pay a little now Or pay a lot later.
electricitym

Henry Kolesnik:
It is NOT "intermittent ESR" that is the problem, rather it is that maybe
some electrolytics have developed high ESR and are operating just at or near
the threshold of the circuitry operating correctly... (see the reply post
from Tim Wescott).
At this point you have been given sound technical advice to check for
circuit board solder connections and to suspect the electrolytics......
until you perform this important initial suggested troubleshooting there is
not much more that you can do ??? Get this fixed right away before it
fails completely as you have previously been cautioned.
electricitym


"Henry Kolesnik" wrote in message
news
As of this moment it has run over 26 hours without shutting down. I've
never seen any evidence that ESR can be an intermittent phenomena. Can
someone please tell me how intermittent ESR comes about?

Henry Kolesnik wrote:

As of this moment it has run over 26 hours without shutting down. I've
never seen any evidence that ESR can be an intermittent phenomena. Can
someone please tell me how intermittent ESR comes about?

Who ever said ESR had to be intermittent to cause intermittent problems?

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Henry Kolesnik wrote:
As of this moment it has run over 26 hours without shutting down.
I've
never seen any evidence that ESR can be an intermittent phenomena.
Can
someone please tell me how intermittent ESR comes about?


The measured ESR of an electrolytic capacitor changes with
temperature.... usually ESR decreases slightly. If the power supply
circuit is just at the threshold of operating correctly then very
slight changes in the ESR of critical capacitors will certainly affect
how the power supply operates and sometimes it can cause a catastrophic
failure of other components. Cold or cracked solder connections can
also cause similar intermittent symptoms.
The repair suggestion replies you have been getting to your original
posting are your FIRST troubleshooting and testing steps; otherwise we
are all guessing here.

wrote in message
ups.com...
Henry Kolesnik wrote:
As of this moment it has run over 26 hours without shutting down.
I've
never seen any evidence that ESR can be an intermittent phenomena.
Can
someone please tell me how intermittent ESR comes about?


The measured ESR of an electrolytic capacitor changes with
temperature.... usually ESR decreases slightly. If the power supply
circuit is just at the threshold of operating correctly then very
slight changes in the ESR of critical capacitors will certainly affect
how the power supply operates and sometimes it can cause a catastrophic
failure of other components. Cold or cracked solder connections can
also cause similar intermittent symptoms.
The repair suggestion replies you have been getting to your original
posting are your FIRST troubleshooting and testing steps; otherwise we
are all guessing here.


Just a guess here, as I may have missed a post or two, but does the unit
shut down "completely" to where nothing can be traced through to see where
it stops? IF not, maybe try that too. I agree with the rest otherwise.

L.