yet another ESR meter thread

[Ray L. Volts]

Out of curiosity, who among you own and/or use both a Sencore Z-meter
(pre-LC103) and one of the portable, dedicated ESR testers? How does the
latter stack up against your Z-meter in terms of measurement speed, accuracy
and ruggedness? Which do you use more often on your bench?

What's your take on Sencore's assertions below. That it's marketing hype is
a given, but do the following also happen to be true and troublesome in your
experience with the portable testers?

"Normal ESR limits vary between aluminum and tantalum types and their
values. Small value electrolytic capacitors; 0.1, 0.22, 0.33, and 0.47 µFd
are now common among electronic circuits. ESR on electrolytic capacitors
above 1000 µFd is less than 0.5 ohms requiring 0.01 ohms of resolution for
good/bad testing. Testers that only test ESR do not accurately test
capacitors below 1 µFd and do not provide the resolution to good/bad test
ESR on capacitors over 1000 µFd."

and

"In circuit capacitor and inductor testing accuracy is plagued with many
parallel components and circuit paths. In-circuit ESR only testers often
miss bad capacitors in-circuit when they are reduced in value, shorted or
leaky. This can add hours to a repair job."

Would one of the ESR-only meters be a recommended investment, given that I
already own an LC-75 and don't currently do field work? Or should I bite
the bullet and just use that cash toward an eventual purchase of the LC103
(which does the in-circuit tests)?

Thanks,
Ray

 

[Leonard Caillouet]

I use the LC105 on the bench and have both the DSE and Atlas for portable
use. They all give slightly different readings but are close. The
advantages to the Sencoreare the capacitance, DA measurement, DC leakage
readings. I have found lots of caps with the DA test that were marginal or
bad causing some strange problems. You can measure cap value with a lot of
DMMs or the Atlas, so that is not a big deal to me. Can't comment on the
older Sencore stuff, other than it is likely built better than the new. We
have had nothing but problems with every Sencore unit in the lot that we got
in about 1999.

Leonard

 

[John Bachman]

I provide a different perspective to these questions as we are the US
distributor of the Atlas and other Peak products. See theAtlas ESR60
at www.anatekcorp.com/testequipment/atlasesr60.htm. The ESR60 also
measures the capacitance of the unit under test, other dedicated ESR
meters do not do that. And it is very portable, of course.

However, what do I use regularly on my bench? My trusty Sencore
LC-75. That unit measures much more than ESR and therefore occupies a
prime spot in the equipment rack and the leads are always at the
ready.

I believe the most or all of Sencore's discussion about ESR is
accurate. The technician has to understand the minutia of ESR to be
able to use these instruments competently.

I get calls all the time from guys wanting to know only one thing,
"Will the ESR60 tell me if the cap is good or bad?" My answer is
always the same, "The ESR60 will tell you ESR and value of the cap.
You have to combine that data with your knowledge about capacitors to
make the good/bad decision."

If it was easy everyone would do it.

John
AnaTek Corporation
The Electronic Repair Center at www.anatekcorp.com

 

[Mark D. Zacharias]

Out of curiosity, who among you own and/or use both a Sencore Z-meter
(pre-LC103) and one of the portable, dedicated ESR testers? How does the
latter stack up against your Z-meter in terms of measurement speed,
accuracy and ruggedness? Which do you use more often on your bench?

What's your take on Sencore's assertions below. That it's marketing hype
is a given, but do the following also happen to be true and troublesome in
your experience with the portable testers?

"Normal ESR limits vary between aluminum and tantalum types and their
values. Small value electrolytic capacitors; 0.1, 0.22, 0.33, and 0.47 µFd
are now common among electronic circuits. ESR on electrolytic capacitors
above 1000 µFd is less than 0.5 ohms requiring 0.01 ohms of resolution for
good/bad testing. Testers that only test ESR do not accurately test
capacitors below 1 µFd and do not provide the resolution to good/bad test
ESR on capacitors over 1000 µFd."

and

"In circuit capacitor and inductor testing accuracy is plagued with many
parallel components and circuit paths. In-circuit ESR only testers often
miss bad capacitors in-circuit when they are reduced in value, shorted or
leaky. This can add hours to a repair job."

Would one of the ESR-only meters be a recommended investment, given that I
already own an LC-75 and don't currently do field work? Or should I bite
the bullet and just use that cash toward an eventual purchase of the LC103
(which does the in-circuit tests)?

Thanks,
Ray

We use a Sencore (not too old but don't remember the model) and a
Capanalyzer (or similar name) that we got from MCM.

Use the Capanalyzer over the Sencore at least 10 to 1. It's just that much
quicker and easier. Also, you can measure in-circuit with a high degree of
reliability.


Mark Z.

 

[Leonard Caillouet]

As I said, I really like and use the Atlas ESR60. While it does provide cap
value, it is rarely going to give that value accurately in circuit. I find
it most useful as an ESR meter. For out of circuit testing I use the
Sencore, because it catches DA problems.

Lots of folks want an easy answer. In the real world it is rarely going to
happen.

Leonard

 

[Bob Urz]

I provide a different perspective to these questions as we are the US
distributor of the Atlas and other Peak products. See theAtlas ESR60
at www.anatekcorp.com/testequipment/atlasesr60.htm. The ESR60 also
measures the capacitance of the unit under test, other dedicated ESR
meters do not do that. And it is very portable, of course.

However, what do I use regularly on my bench? My trusty Sencore
LC-75. That unit measures much more than ESR and therefore occupies a
prime spot in the equipment rack and the leads are always at the
ready.

I believe the most or all of Sencore's discussion about ESR is
accurate. The technician has to understand the minutia of ESR to be
able to use these instruments competently.

I get calls all the time from guys wanting to know only one thing,
"Will the ESR60 tell me if the cap is good or bad?" My answer is
always the same, "The ESR60 will tell you ESR and value of the cap.
You have to combine that data with your knowledge about capacitors to
make the good/bad decision."

If it was easy everyone would do it.

John
AnaTek Corporation
The Electronic Repair Center at www.anatekcorp.com

I have got on older LED sencore on the bench and a batt op ESR meter.
I use the portable cheapy one a lot more than the Sencore, but the
sencore does more. The portable ESR is used in circuit all the time.
If i am doubt, i pull the cap out and put it on the sencore.
I can also do voltage breakdown tests on the sencore.
It's not so much apples an oranges, but two different kinds of apples.
The Sencore is NOT a good quicky in circuit test like the bat op Z meter
is. Out of circuit it wins hands down.

Bob

 

[[email protected]]

Let me start by saying I haven't used one of the small ESR meters,
although from the vast number of positive comments I've read about the
Bob Parker model, I don't believe that there is a more effective unit
in that price range.

I've used several models of the Sencore LC analyzers, and the most
difficult aspect of in-circuit testing is dealing with the original
equipment Lo Capacity (actually low capacitance) test cable with the
mini-grabber hooks.
Sencore suggests that their 3-spike probe accessory 39G85 Touch Test
Probe can be used with the LC cable mini-grabber hooks, for probing
circuit boards on the solder side.

The Sencore tweezer accessory (looks like a divider) probe is
adjustable and has sharp points for probing boards, although the $99
price might be ojectionable to many occasional users, like myself.

I found out by experimenting, that the LC76 model can be used with a
common pair of test probes (and a BNC-bananna adapter), for in-circuit
capacitor Value and ESR checks. The LC76 has a zeroing pot on the front
panel which is used to set the display to 0.00 ohms with the lead tips
shorted, prior to doing in-circuit ESR checks.
This method may also work well with the earlier models.
Holding 2 probes in one hand, the ESR button can be reached with the
free hand, still not especially comfortable, but not so difficult with
a little practice.

Of course, one would not attempt to check in-circuit components for
Leakage.. bad idea.

The LC77 and newer models are more sophisticated, and don't accept the
characteristics of probe leads (errors are displayed when the test lead
Open/Short setup is performed). The LC input cable type is 93 ohm
impedence RG-62B/U which has a low capacitance of about 13pF per foot.
The original LC cable is a section of RG-62B/U with a short length of
RG-174U going to the + hook.

I didn't particularly like the idea of using the grabber hooks attached
to the TT probe, with the loose connections of the hooks when checking
for low ohms, so I made a probe with a section of RG-62B/U cable and a
modified 39G85 probe. A hole was drilled in the probe top end for the
coax to enter, then discarded one spike and soldered lengths of
finely-stranded flexible wire to the remaining 2 spikes. Short lengths
of black and red shrink tubing were placed on the outside/visible ends
of the spikes to identify them as +/coax center conductor, and
-/shield.
The spike tips don't flex far enough to pinch them together to perform
the lead Short setup, but lightly jabbing them into a piece of clean
metal (a coin, for example), will set the input circuit properly. To
check that the input is zero, press ESR and Coils - Inductor Value to
confirm readings of 0.00 (while the tips are still shorted).
Not having to hold 2 probes with one hand (chopsticks position) is
convenient. A similar probe body could be fabricated from plastic
tubing or similar material.

The complete analyzer features of the Sencore LC units makes them very
versatile instruments. The additional features can often be used for
many types of testing.

Additionally, the ESR ohms measurement is reliable for checking low
value resistors (out-of circuit), for those users that might not have a
milliohm meter.

Inconsistent readings on LC meters can be caused by a poor connection
at the front panel cable BNC connector. This is a key element in the
test circuit. High quality panel and cable connectors are best, and
routine inspection and cleaning will eliminate problems. I usually
clean the center conductor contacts with DeoxIt (on a toothpick for the
female contact) to remove any oxidation, especially if the analyzer
hasn't been used for a considerable time.
The test connector internal wiring is switched thru relays, and worn or
oxidized contacts can also contribute to inconsistent readings.

Cheers
WB
.................

 

[Ray L. Volts]

Looks like the thread's dead, so I'll say my followup thanks to all for your
input.