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)?
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.
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
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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
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.
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.
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
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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.
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