So do you know of any available testers that have these options? Why don't
you suggest that Bob Parker update his design...
Not that it matters much in this case. The point was that in many of these
sets the problem is due to the electrolyte itself and not the performance of
the cap. I tested one just a few days ago that had one leg mostly corroded
off and it passed all the tests on my Sencore. You can test any way you
want and if you don't LOOK for the obvious problem you won't be successful
in fixing these sets.
Leonard Caillouet
"Leonard Caillouet" bravely wrote to "All" (02 Jan 04 20:38:30)
--- on the heady topic of "Re: Mitsubishi TV"
The problem with most esr meters is that they use a rather high
frequency of about 100K Hz to keep the reactance of small electro values
negligible. The problem with this strategy, in my experience, is that
large value electros can test good with the higher frequency because the
outside layers can behave as a perfect small electro and yet indicate
very little esr, since the inner layers are in effect bypassed. Not all
bad large electros behave this way but enough do to make a difference.
As such having a range of about 3 test frequencies would be helpful.
For example 100K Hz is great for electros of 10uF and less to about
0.1uF. 33K Hz is good from about 10uF to about 470uF and 10K Hz for
anything larger than about 470uF up to about 10mF. Then 3.3K Hz for even
larger values, etc.
LC> From: "Leonard Caillouet" <
[email protected]>
LC> Well, almost correct, David, but ESR tests will not get many of the
LC> capacitors that are physically leaking electrolyte, which is the
LC> bigger problem in many of these sets. You have to visually inspect
LC> them and/or heat the leads and smell the results. I have seen many
LC> caps that are leaking electrolyte that pass all tests, including ESR.
LC> Leonard Caillouet
.... Resistance Is Futile! (If < 1 ohm)