Hi Group,
FYI: I repair a lot of Ten Tec boards and especially Omni 6 logic boards and
Paragon boards in general.
About 2 years ago, I bought an ESR meter to better evaluate the electrolytic
capacitors on these boards in areas
where I was finding faults. As suspected, MANY of the electrolytic caps are
measuring high AC resistance. I find almost 3 to 4
caps reading above 15 ohms on every board. And replacements I install are
typically well under 2 ohms.
The question becomes how necessary is it to replace these caps. In some cases,
I see improved filtering and resolve go no go faults.
In other cases, little to no difference is observed in functionality.
Given the age of theses boards, it is not unusual for some of these caps to be
marginal. In my case, I replace any cap that is not measuring
below 3 to 4 ohms. Just because it works today does NOT mean it will continue
to work. If I can save a client a headache in a year or two I am happy
to do so. This adds some cost to the final invoice but over time it is a win
win deal for the client and my business; My back log is always long and I hope
our customers have excellent results from our work.
I built my first ESR meter and had an analog meter but decided to buy one by
ANATEKCORP dot com. It is called the Blue ESR meter.
It was a kit and cost $80 or $100 assembled. It took about 4 hours to build and
align and it works GREAT.
I did toss the cheap test lead wire that came with the kit and used real Test
Lead cable and like that MUCH better. I also tossed the alligator clips that
were supposed to be used fro grabbing cap leads and replaced them with self
locking logic clips; MUCH BETTER.
I find I use this piece of equipment almost as much at I use my DVM or trusty
Simpson 260P.
Just one other note. I buy a lot of caps on line from epray many or maybe all
made in Asia. I have to say they work great and have LOW ESR values of
typically less than 1.5 ohms and spec to correct values on my Wavetek Capacitor
tester. They are speced at 20% but my readings always indicate better than 2%.
I am in NO way related to or do any work/ business with Anatek but they do have
some great products. I just bought the inductor ring tester ($52 kit) which I
can simulate with a function generator and AC volt meter but this unit is a
calculator size box that I can quickly take from bench to bench. It has been
invaluable to find leaky caps across coils sinking back EMF as well as coils
with faults. I have found numerous bad caps and coils on R 390A receivers I
work on with this cheap tester.
They also have a slick transistor/FET tester. I have used analog meters for
decades to test these devices and I have a Curve tracer as well but again, this
is a small box that moves around my lab easily. My Tektronix 576 curve tracer
is great but weighs 90 pounds. I have not purchased the transistor tester yet
but will do so soon. It has a processor and will ID the device you hook up as
an NPN, PNP, Darlington and on and on. My Simpson requires my to find out what
I am testing by other means.
Hope this helps.
73,
Glenn WA4AOS
DSM Labs (dot com)
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