E.S.R. meter- Whats the big deal?
John R.Hepburn
First off, I am not saying the products sold do not do what is stated or
that the theory behind it is wrong , it just seems that a mountain is being
made out of a molehill.The problem power supplies also seems to be portrayed
as something new when in fact we all have been dealing with it since day one
of d.c. power sources being derived from flyback transformers.
1) Electrolytics are poor filters at high frequencies just by their physical
construction. That is why you will see a 0.1 mf disk capacitor paralleled to
470mf whenever there is reason to believe that very high freq. could be on
the lines. This is because electrolytics have an inductive component just by
the nature of winding the capacitor plating into a coil. Never heard anyone
mention that when talking about the nature of electrolytics and how e.s.r.
will cause a h.f pass. Come on , an e.s.r. meter and a bag load of new
elec. capacitors will not get rid of very high frequencies, only a parallel
disk cap and/or series inductor will do that, but then why is it there in
the first place. If a very slightly degraded electrolytic is causing it to
reach the problem point ,then it is probably poor design work and should
have had a disk cap added in the beginning.
2) Yes ripple increases as resistance decreases but the resistance is not
necessarily constant as the voltage goes up. I fail to understand what the
600mv pulses detects that a Mohm meter will not. If the test was being done
at 90% rated voltage then I could see it. Say it is starting to fault at 5v
neither way mentioned is any darn good
3) How is it better to power down the unit , discharge the caps then clip on
the 'fad' e.s.r. meter. Would it not be easier to clip on your scope while
it is running and observe? If someone says "Clipping on the scope makes the
problem disappear" then given it is a capacitor, that should tell you more
than you need to know. If the problem is still there, then you will see what
the circuit is seeing, again that should tell you more than you need to
know. Quite frankly I can check 20 caps in the time it takes someone to
power down and discharge for that test.
I have a deluxe H.P. unit for evaluating inductors and capacitors but it is
only used to determine the "Q" and true value of the part in order to know
its ability and limitations as a resonator or filter component. Never used
it or felt the need to in order to find bad electrolytics in a pulse power
supply.
Unless I am missing something (maybe I am....feel free to correct) I get the
feeling this tool is just finding its market as crude compensation for lack
of electronic knowledge and/or an oscilloscope.
John R. Hepburn
John's Electronic Services
jhep...@recorder.ca
Mzacharias
First of all, I don't own an ESR meter as such, but use a "curve tracer" with
an oscilloscope, which tests roughly for ESR. I would say, though, that the
main elements in favor of an ESR meter are its speed (don't have to desolder
components) and its' low cost. How much did your "deluxe HP unit" cost (or for
that matter my Sencore Z-meter) ? One of the most highly regarded individuals
in Sonys' technical support/repair unit hands out literature on a low-cost ESR
meter before each new class (and no, he has no financial interest).
As for the abilities of these techs, I believe that each time we incorporate a
new technique which helps us to "get it" a little more, then so much the
better. There are so many bad caps these days (ex. camcorders) that I feel a
quick go/no go test is invaluable for daily use in repair shops.
Mark Z.
Wichita, KS.
Pete Peterson
John,
Is the ESR of today what we called "Power Factor" in the 50's and 60's? I
built a Heathkit capacitor checker with the green cat's eye that measured
power factor in 1959. I don't remember finding a lot of troubles with it
though. Also am I correct in saying the metal can of today's electrolytics
is not connected to the negative lead? All of the ones I have checked
lately were not connected, but years ago they were and the can was a
convenient place to pick up a ground connection. I am starting to service
a number of SMPS' now and I can see that if the can was connected to the
negative lead, it may not be wise to use it for a common since there are
two separate ones. Anyway I am considering getting an ESR meter since so
many folks seem to have good success with them. Thanks for your input.
Pete
Mzacharias <mzach...@aol.com> wrote in article
<199805032114...@ladder01.news.aol.com>...
John R.Hepburn
, I believe that each time we incorporate a
>new technique which helps us to "get it" a little more, then so much the
>better. There are so many bad caps these days (ex. camcorders) that I feel
a
>quick go/no go test is invaluable for daily use in repair shops.
>
>Mark Z.
>Wichita, KS.
But isn't that what a scope does. It may not tell us the nature of the
fault, but who cares, I am not repairing it ,I am replacing it. Don't get me
wrong, if someone could show me how it would save me 1 minute in a day, I
would buy it tomorrow. An example would do , and explain why the circuit can
"see" the bad voltage , but my scope can not.
As far as the Sony guy goes, I have known enough company technical reps to
know that they know not everyone in the class is up to speed technically.
Their mandate is to do what it takes to make their products look good. If an
e.s.r. meter in the hands of the few who are having problems will keep a few
customers from long waits at the repair shop, then they probably would
endorse it. How do they know some are having problems? Too many complete
power supplies being ordered . Don't you think a few customers have let
them know their intent not to buy their product again after seeing the major
repair bill on a 2 year old v.c.r? I have won a lot of new customers on
'complete power supply' second opinions. Dam e.s.r. meters are going to cut
into my business!!
ma...@global.california.com
"John R.Hepburn" <jhep...@recorder.ca> wrote:
>First off, I am not saying the products sold do not do what is stated or
that the theory behind it is wrong , it just seems that a mountain is
being made out of a molehill.The problem power supplies also seems to be
portrayed as something new when in fact we all have been dealing with it
since day one of d.c. power sources being derived from flyback
transformers.
The bad effects of high esr are not limited to 'lytics in power supplies.
My Sony TV has several dried out 'lytics in its vertical oscillator
section which are easy to locate if you remove them one by one and check
them using a spectrum analyzer with function generator option. It's a lot
easier to leave them in the circuit and check them without having to
desolder them.
>1) Electrolytics are poor filters at high frequencies just by
...clip....
it to reach the problem point ,then it is probably poor design work and
should have had a disk cap added in the beginning.
For straight filtering, seems reasonable.
>2) Yes ripple increases as resistance decreases but the resistance is not
necessarily constant as the voltage goes up. I fail to understand what the
600mv pulses detects that a Mohm meter will not. If the test was being
done at 90% rated voltage then I could see it. Say it is starting to fault
at 5v neither way mentioned is any darn good
I've never been able to use a Mohm meter to measure esr. Not sure how you
propose to do that. Unless it's used to read the Vrms ripple across the
cap during operation, but that would be a DVM. Then again, some DVM's
include the DC in their AC readings.
Don't know whether a 'lytic's esr changes abruptly as a function of the
operating voltage, or not.
>3) How is it better to power down the unit , discharge the caps then clip
on the 'fad' e.s.r. meter. Would it not be easier to clip on your scope
while it is running and observe? If someone says "Clipping on the scope
makes the problem disappear" then given it is a capacitor, that should
tell you more than you need to know. If the problem is still there, then
you will see what the circuit is seeing, again that should tell you more
than you need to know. Quite frankly I can check 20 caps in the time it
takes someone to power down and discharge for that test.
I didn't like clipping my scope onto 140V circuitry which was not
referenced to ground if I didn't have to, plus using only one lead I
couldn't tell much about what was wrong in that vertical osc section to
begin with. Only that the osc's output was "folded" over.
It was a lot easier to use a small portable clip on meter that gave
instant readings than it was to haul everything over to test the TV.
>I have a deluxe H.P. unit for evaluating inductors and capacitors but it
is only used to determine the "Q" and true value of the part in order to
know its ability and limitations as a resonator or filter component.
Never used it or felt the need to in order to find bad electrolytics in a
pulse power supply.
Nice instrument. What frequency does that run at? Isn't it 1KHz?
You're probably right that you do not need to check for a bad cap with a
dedicated esr meter while the rest of the circuit is running.
It sure helps to be able to check for a bad cap with a dedicated little
meter *IF* that bad cap keeps the circuit from running properly.
>Unless I am missing something (maybe I am....feel free to correct) I get
the feeling this tool is just finding its market as crude compensation for
lack of electronic knowledge and/or an oscilloscope.
I've got four scopes, two f. generators, spectrum analyzer w tracking gen
option, six DVM's, three cap meters, a four point from Stanford graduate
school (plus 32 years of analog design experience) and I consider it a
useful addition to my lab's instrumentation.
- Robert -
PS I've started using it to check for "bad" cabling connections. I used
to have to do that with 4 point measurements.
Dave Moore
Well John,,,,
I felt pretty much the same way as you as I've
been doing just fine without one for years.
But I thought I'd get one and see for myself what
the hoopla is all about. I must say that I have really
saved some time on some repairs and where in
the past I usually found the bad caps that were causing
the particular problem, I now due to the speed and
ease of in circuit testing, check bunches of caps in
other circuits to boot and sometimes sniff out potential
problems that may be impending. Geez $50 bucks for
Bobs meters,,,, I bought 2 of them.
Also,, Bobs meter is very usefull to me for low ohms
testing since it has the zeroing feature, you can just
zero it to compensate for lead resistance and get a
direct reading. Great for checking those emitter resistors
in audio output stages. I have also flagged a few bad
caps that my regular cap checker said were good.
The reason I got one is due too the increased amount
of tv's and vcr's that use SMPS's. Not that SMPS's haven't
been around, it's just that the number of them has
dramatically recently.
I almost did a post very similar to yours stating that I
have been fixing SMPS's without an esr meter, so who
needs one. Well I'm definetly sold on them now and
find that speed and thoroughness are 2 of it's best selling
points. Try it,,,,, You'll like
=^^= Dave Moore
WMckee1067
whatever happened to plain old shotgunning the caps
to find the culprit
Jason D.
Big snip!
> - Robert -
>
>PS I've started using it to check for "bad" cabling connections. I used
>to have to do that with 4 point measurements.
>
What about this quick check to see if the video head is good with that
ESR meter? I knew the frequency might effect the reading but I did
that on one vcr yesterday with strange problem. It's flickering like
mad (30hz instead of 60hz) with wide black band and a thin band with
parts of the video at bottom. AND VERY touchy, better signal with top
cover on even w/o screws. The "resistance" difference is not close
each other: 1.3 on one and other wildly different off or no readings
every time I try there.
Jason D.
Oldguyteck
Same thing I recon happened to us ole tube jockies heheh sorta got
discarded for the newer/newfangled things LOL <<<TIME IS
MONEY>>>
Ed..........................(Oldguyteck)
WMckee1067 <wmcke...@aol.com> wrote in article
<199805040141...@ladder03.news.aol.com>...
Michael Caplan
John:
It's a tool, just like your scope. In this case, it is a tool
designed, initially, for a specific purpose. And, from my experience,
and it appears that of others, it is a timesaver.
Yes, there is test equipment that is designed to compensate for a
lack of knowledge/training. I don't think that's the case here.
Just like a scope can be used by someone with a good background, or
with someone with little knowledge, so it is the case with the ESR
meter. The difference is in knowing how to use the device, and more
importantly, interpret, the results. The ESR meter I have (DSE) still
requires me to understand what I am measuring and to make an informed
judgement/decision. That's where my knowledge and experience come in.
I tend to work down to the component level, rather than changing whole
modules, pcbs etc. In some VCRs, for example, the SMPS is in a
closed shield case that precludes connecting test equipment while the
ps is in place. The module is easy to remove and uncover, but then it
is not connected to the load. Rather than subbing a load, powering
up, and making "live" measurements, I find it far easier to pull the
module, snap off the shield cover, and test the caps in a couple of
minutes with my ESR meter. The use of other test methods and other
test equipment rather than an ESR meter is perfectly valid and I have
no argument with that. However, I think that in many if not most
instances (I agree, not all instances) the ESR meter has the edge.
I posted an article some time back on the issue of "Q", or dissipation
factor versus ESR. That was on Aug 16, 1997, titiled: "ESR Meter --
follow up". "Q" is directly related to what is being called "ESR",
but the "Q" that is measured by most devices is frequency-dependent,
and so has to be interpreted. ESR is a direct measurement.
(There's more in the posting. If you cannot find it let me know.)
Michael Caplan
ma...@global.california.com
Well, it's that "cost" called time. I can always make more money when I
spend it, but I can NEVER make back the time I've spent. <g>
- Robert -
bob parker
Hi everyone,
I didn't know this discussion was going on until Michael Caplan
just told me, and I thought I'd add my two cents' worth about why I
designed the Dick Smith Electronics ESR meter in the first place.
I'm also a service technician, and for a while I was fixing a lot
of switching power supplies for our main telecommunications authority.
As Michael said, it was physically impossible to look at ripple
waveforms while they were powered up and under load, and I wanted to
be able to check the condition of the electrolytic caps while they
were accessible- i.e. with no power connected. I've never been keen on
simply replacing complete sets of caps just to make sure I get the
defective one or two which might be causing a problem.
I've also had to fix a lot of TVs and VCR power supplies, and as
Robert pointed out, it's not real safe to connect oscilloscopes to the
rectified mains to check ripple waveforms on the "HOT" side of
switching supplies (if they are accessible while operating). The mains
here is 240V, and I'd rather not disconnect the ground from my scope
then connect its chassis to about 340V peak!
OK so you can use an isolating transformer, but if you're trying to
check electrolytic coupling caps in switching supply primary side
control circuitry, the capacitance of the scope chassis back to ground
can cause all kinds of trouble anyway.
Back in early 1996 I wasn't on the net and couldn't find anything
about ESR meters here in Australia, so I designed my own out of sheer
frustration. As I'd hoped, it's saved me heaps of time- and was more
useful than I expected it to be. Ultimately the design was published
in a magazine and then became available as a kit.
You can call ESR meters a "fad" if you like, but my suspicion is
that they have become popular because they really do save time. I've
received over a dozen e-mails plus more messages in my web site guest
books, thanking me for the time the Dick Smith ESR meter has saved.
From what I've heard, most techs buy ESR meters because their friends
recommend them- not because they are advertised on the net and in
technical magazines.
As for this statement about 0.1uF disk ceramic caps taking care of
high frequency ripple, a bit of theory shows that even at 500KHz, a
0.1uF capacitor has a reactance of around 3 ohms... hardly adequate to
filter all the ripple from a switching supply operating at 50KHz, let
alone a horizontal output stage at about 16KHz. The electrolytics
still do nearly all the filtering in switching supplies, otherwise why
design them into the circuit? As far as I can tell, the disk ceramics
are there to control *really* high frequency noise up in the megahertz
part of the frequency spectrum which could otherwise get into signal
circuitry.
Finally, THANK YOU to the techs who've supported the principle of
ESR testing in this discussion! I would still be enthusiastic about
ESR meters even if I'd gone out and bought a Cap Wizard etc (if they'd
been available) rather than designing one myself.
bob parker- electronics technician, sydney australia
e-mail: bo...@nlc.net.au
home page: http://www.nlc.net.au/~bobp/
phone/fax: +61 2 9587 8148
bob
We just put together two kits for our shop, and I must tell you that I
could not be any happier. They work great! My first use of one of the
meters showed a cap bad for ESR, but the capacitance tested ok. It wasn't
a typical problem cap. The ESR meter is a time saver, Thanks Bob.
fixtron@remove,aol.com
Ren Tescher
In article <199805040141...@ladder03.news.aol.com> wmcke...@aol.com (WMckee1067) writes:
>whatever happened to plain old shotgunning the caps
>to find the culprit
Because now you can find all the bad caps, leave the good ones in,
replace the bad ones, take 'em out back and "shotgun" them there.
Less co-lateral damage to the rest of the circuit by flying pellets!
B^)
Ren
dona nobis pacem
John Tournant
Bob,
I would like to reiterate my comments, made shortly after obtaining
one of your ESR meters, just over a year ago: It was the best
investment I ever made! and the price was £20 sterling, complete!
I never knew, then, what ESR was, in spite of working in the
electronics industry for some 50 years
and I only read about it in the newsgoups.
It certainly is easy to assemble; it works very efficiently in
detecting failing electrolytic capacitors, in or out of circuit, AND
it's also a very accurate low resistance meter.
Thank you, Bob and kind regards,
john.
in Cambridge UK
MClark7254
I been hearing a lot about the e.s.r meter and hearing your testimony about its
capabilities is interesting. Could you please inform me where I could purchase
this piece of test gear. Thanking you in advance, Mike Clark
bob parker
mclar...@aol.com (MClark7254) wrote:
The info about the Dick Smith Electronics ESR meter is at:
http://www.nlc.net.au/~bobp/esrmeter.htm
Thanks for your interest!
Bob
bob parker
r...@rap.ucar.edu (Ren Tescher) wrote:
Hee Hee Heee!! Nice comment Ren- sorry it took so long to post this!!
John R.Hepburn
bob parker wrote in message <3575a60c.15370186@news>...
O.k Bob, you have a convert. I started this thread, but after a lot of
input from my peers I am starting to see how it could be a time saver in
certain applications.I hope you did not view this post as being negative, I
just felt a little game of "Devils advocate" would bring out the truth. I
will admit it held up well, which to me is the sign of a good product.
So, if you would tell me where to go (be nice) to get info and to order this
gizmo, it would be appreciated.
Oh, if you also sell calculators , don't send any info on that......I hear
the slide rule is making a comeback.
bob parker
"John R.Hepburn" <jhep...@recorder.ca> wrote:
>O.k Bob, you have a convert. I started this thread, but after a lot of
>input from my peers I am starting to see how it could be a time saver in
>certain applications.I hope you did not view this post as being negative, I
>just felt a little game of "Devils advocate" would bring out the truth. I
>will admit it held up well, which to me is the sign of a good product.
>
>So, if you would tell me where to go (be nice) to get info and to order this
>gizmo, it would be appreciated.
>
>Oh, if you also sell calculators , don't send any info on that......I hear
>the slide rule is making a comeback.
>
>John R. Hepburn
>John's Electronic Services
>jhep...@recorder.ca
>
Hi John (and others?),
I didn't think anyone would be reading this old thread!! I had a
feeling you were "objecting" just a tad 'too' strongly to the idea of
doing ESR measurements on electrolytic caps.....
As you've seen from the comments, the main thing going for passive
ESR testing is the time saved by not having to power up the equipment
and take safety precautions, or have everything connected in its
normal configuration. You can pull a switching supply out, take it
apart, and quickly check the caps on your bench. And of course time is
the most important commodity us techs never have enough of!
Thanks for your your part in getting everyone to discuss this
subject!!
Anyway, to answer your question about how to get hold of the Dick
Smith kit, please take a look at:
<http://www.nlc.net.au/~bobp/esrmeter.htm>. Don't forget there is
information on the Capacitor Wizard (nice US-made unit) at:
<http://www.awiz.com>. If you want to know more about the background
on the Dick Smith unit, go to:
<http://www.nlc.net.au/~bobp/esrtext.htm>.
Nice to hear from you, and I won't even mention calculators!! ;-)
Regards,
jaj...@bellsouth.net
John R.Hepburn wrote:
>
> Oh, if you also sell calculators , don't send any info on that......I hear
> the slide rule is making a comeback.
I'm thinking about marketing a line of excellent solar-powered slide
rule kits! Let me know if you're interested. :-)
--
James A. Jones
Team OS/2
Baton Rouge, LA
--------
bob parker
jaj...@bellsouth.net wrote:
YES PLEASE.... But they have to be able to operate correctly upside
down, since I'm in Australia.
Ren Tescher
In article <35829a1c.5362224@news> bo...@nlc.net.au (bob parker) writes:
>jaj...@bellsouth.net wrote:
>>John R.Hepburn wrote:
>>> Oh, if you also sell calculators , don't send any info on that......I hear
>>> the slide rule is making a comeback.
>>I'm thinking about marketing a line of excellent solar-powered slide
>>rule kits! Let me know if you're interested. :-)
>YES PLEASE.... But they have to be able to operate correctly upside
>down, since I'm in Australia.
Your post and the one from the Australian selling math books has
got me wondering...
When doing division down there,
do you put the denominator on the top or the bottom of the
fraction line?
I mean if I use an Australian calculator will all my answers
be
1
_
x
?
Do they have RPN Australian calculators?
Sam Goldwasser
I don't understand why your postngs don't come out upside-down as well :-).
--- sam : Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Latest Sam stuff: http://www.repairfaq.org/sam/
Lasers: http://www.repairfaq.org/sam/lasersam.htm
http://www.misty.com/~don/lasersam.html
Stan Blazejewski
On 15 Jun 1998 22:31:21 GMT, s...@stdavids.picker.com (Sam Goldwasser)
wrote:
WHAT!, you mean our messages come the right way up for you???
>I don't understand why your postngs don't come out upside-down as well :-).
>
> In article <35829a1c.5362224@news> bo...@nlc.net.au (bob parker) writes:
> >jaj...@bellsouth.net wrote:
> >>John R.Hepburn wrote:
>
> >>> Oh, if you also sell calculators , don't send any info on that......I hear
> >>> the slide rule is making a comeback.
>
> >>I'm thinking about marketing a line of excellent solar-powered slide
> >>rule kits! Let me know if you're interested. :-)
>
> >YES PLEASE.... But they have to be able to operate correctly upside
> >down, since I'm in Australia.
>
> Your post and the one from the Australian selling math books has
> got me wondering...
>
> When doing division down there,
> do you put the denominator on the top or the bottom of the
> fraction line?
--
Australia isn't "down under", it's "off to one side"!
stan...@netspace.net.au
http://www.netspace.net.au/~stanblaz/
(home of the Cobra Catamaran)
Asimov
stan...@netspace.net.au said the following to All on the subject of
Re: E.S.R. meter- Whats the big deal? (17 Jun 98 06:05:22)
st> On 15 Jun 1998 22:31:21 GMT, s...@stdavids.picker.com (Sam Goldwasser)
st> wrote:
st> WHAT!, you mean our messages come the right way up for you???
>I don't understand why your postngs don't come out upside-down as well :-).
> When doing division down there,
> do you put the denominator on the top or the bottom of the
> fraction line?
st> Australia isn't "down under", it's "off to one side"!
Just out of curiosity I did the math and it turns out a straight line
right though the Earth places my city, Montreal, just slightly
North-West of Perth. To my location, you really are "down under".
--
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