ESR meters and the Bob Parker unit revisited

[Bob Parker]

Re: ESR meters and the Bob Parker unit revisited

Blue ESR meter kit builders:

As an additional thought triggered by KeriJane's comment about probably not needing to consider all of the stuff in the assembly manual, I would have to say that in the case of this Blue meter, no superfluous stuff was included, so I advise heeding all of the instructions.

Huck

Yep. A substantial number of e-mails asking me for help have been due to people not making the effort to read the instructions properly.

One manifestation of that is when they say, "I tried the self-test function and it gave a F2 warning and I wasted hours replacing parts etc' and I tell them that if they'd read the instructions, they would not have tried it with a 9V battery powering the unit.

[Bob Parker]

Re: ESR meters and the Bob Parker unit revisited

Congratulations KeriJane

I jump in this thread to ask a question: it is enough to measure the cap ESR?
If I'm not wrong this "tester" measure only ESR and not cap value, so is it possible that a cap with bad value tolerance, let's say a 1000uF which is dropped at 600uF, has still an ESR within tolerance?
If this is possible, is it a limit to measure only ESR?

I hope I have not asked a stupid question.

Ciao
Gianni

P.S.: next time I change bad caps and I can measure their value I will check also the datasheet to check how much ESR/Value have changed from spec.

The ESR meter only measures ESR, as its name suggests. If someone wants to measure capacitance, there are lots of cheap multimeters which can do that.

In all my electronic work since the mid 1970s, I've encountered thousands of electrolytics whose ESR was high and causing trouble, but not one whose reduced capacitance was causing a fault.

However I know that reduced-value electrolytic caps do sometimes cause very strange faults, so as my ESR Meter Hints web page says:


"Caution... not all electrolytic caps fail due to high ESR or leakage.

Kevin of Kevin's TV Repair gave this important warning: "Your ESR meter sometimes misses caps that show a good ESR reading, but have a capacitance value of half or less of what they should be. This has only happened twice, but I rely so heavily on your ESR meter that I drove myself crazy trying to find the problem elsewhere! Now I know if everything checks out OK, to pull the caps out of circuit and measure their value."

I've heard of this happening maybe 3 times to other techs, so please keep it in mind if nothing seems to make sense, that the ESR meter might be getting fooled by one of these very unusual caps."

[KeriJane]

Re: ESR meters and the Bob Parker unit revisited

Hello.

Hi Gianni

All that this one measures is ESR. You have to get a separate tester for capacitance value in order to measure that. I noticed that most of the cheap ones only seem to range up to 20uf, which is not useful for most of our low ESR cap troubles. I got the BK Precision 815 component tester which goes far higher.

Ummm... I'm not sure if I made myself clear on my previous post.... I did read the instructions carefully and thought that some of the finer details had been omitted, I was not implying that I skipped over them.


Have fun!
Keri

[Gianni]

Re: ESR meters and the Bob Parker unit revisited

Thanks Bob for the explanation.
So it can happen, very seldom, that good ESR doesn't mean good cap.

@ KeriJane: yes I saw on the vendor site the characteristics. I don't recap a lot of stuff, to be precise I started last summer (I found Badcaps.net ) to really understand how the bad caps plague is spread, so at the moment I don't need an ESR meter.
Anyway if I need an ESR meter, I would prefer to buy the Atlas Meter or something like it. Ok it is more expensive but you can measure values.

At the moment I can use my company LCR Bridge which is a professional equipment but it is good to see that it is possible to build your own ESR meter of good quality starting with a kit.

Ciao
Gianni

[Bob Parker]

Re: ESR meters and the Bob Parker unit revisited

Yay!

I got the Blue ESR kit today.

I put it together, tested it and calibrated it all in one night.

It seems to work ok, right from the start.

It's a nice kit. Thank you, Bob Parker.

Have Fun,
Keri

You're welcome. Glad it went together OK and it's ready to go. There's a lot of info about using it at various websites, e.g. ...

http://www.electronicrepairguide.com/esrmeter.html
http://members.ozemail.com.au/~bobpar/esrhints.htm

Good luck with it and I hope it saves you more time than it took to assemble and set up.

[Krankshaft]

Re: ESR meters and the Bob Parker unit revisited

Keri in the manual to calibrate the low battery POT I believe there was a little regulator circuit you could build to to get 5.5 volts from a 9 volt battery.

It involved a transistor a very common one like Ratshack common , one resistor, and a 10K pot. I think the schematic was in the instructions.

It's not like .5 volts matters anyways just FYI .

[KeriJane]

Re: ESR meters and the Bob Parker unit revisited

Hi Krankshaft

Oh, I saw that little circuit thing allright. But I figured that maybe replacing the battery at 6v instead of 5.5 wasn't going to going to save me all that much on 9v batteries. Unless maybe they have a weird tendency to run nearly indefinitely at 5.6v or so and then rapidly expire from that point.

I read all 12 pages of the instructions but get the feeling that I missed some of the pages. Maybe I should have marked the page numbers on them when I printed them out.

Or maybe I'm just blind in one eye and can't read out of the other!

At least the instructions were very good though I feel they might be incomplete. And lacking page numbers.

Other than my inability to interpret the instructions, the kit is great. Shipping was super fast, the parts nicely separated into orderly little bags with labels, the circuit board is nicely made and laid out, the plastic housing is nice and solid, it's just great. The thing practically falls together.
My BK Precision Component Tester did a great job of verifying all of the resistor and capacitor values before placing on the board. The instructions were perfect all the way up to putting the IC's in. Which is where I keep thinking I missed a page or two.

Have Fun!
Buy the blue one, it's a Keeper!
Keri

PS. Speaking of instructions that have driven me bonkers .... the stuff that I used to read when I was little made me cry! It was so far over my head I thought that I would NEVER grasp any concepts about electricity at all, ever.
The biggest offender was my fathers correspondence course on Radio Electronics from the Cleveland Institute of Electronics. It was clearly written for first-rate college graduate Geniuses (like my father) and most definitively NOT written for curious little girls. I kept reading that pile of white and red workbooks well into my 20's! Nowdays, I actually understand a little bit of it.

[Huckfinn]

Re: ESR meters and the Bob Parker unit revisited

KeriJane:

You are correct in stating that a 9 volt battery that has drooped all the way down to 6 volts under load in the Blue meter doesn't have a whole lot of useful life left in it anyway. By the way, how are you doing with the Owon scope?

Huck

[Huckfinn]

Re: ESR meters and the Bob Parker unit revisited

A GENERAL KIT BUILDERS BIT OF INFO:

A really neat and informative web site gives some nice soldering/desoldering videos and tutorials. Check out their whole site, including some interesting links and references!

The site is: www.curiousinventor.com

Enjoy!

Huck

[KeriJane]

Re: ESR meters and the Bob Parker unit revisited

Hi Huckfinn!

I noticed something with the scope the other day.... The probes seem to work as expected with no spikes when I was checking vCore with a system running.
Replacing the OST caps with Rubycon MBZ seemed to reduce the ripple, though I didn't take any screenshots.

It was nice to get a believable reading out of that thing!

Speaking of which....

A neat feature of the ESR meter is an ability to test caps in circuit.
I was wondering how multiple caps in parallel (as in the above vCore circuit) affect its operation.
Wouldn't the reading be of all 8 caps?

Or is it somehow able to zero in on the cap it is clipped to?

Have Fun,
Keri

[Wizard]

Re: ESR meters and the Bob Parker unit revisited

It will not tell you if the one cap is GOOD and other one is utterly used up in a parallel but the total ESR rises ever so slightly by .5 or 1 even two but the current ripple capacity is totally thrown out thru window.

This situation, I usually unsolder one leg (if board is one layer) or multiple layer, remove all the caps & replace.

Cheers, Wizard

[Huckfinn]

Re: ESR meters and the Bob Parker unit revisited

KeriJane:

As Wizard stated, unfortunately ESR testing becomes more labor intensive when capacitors are hooked up in parallel. Even though as you state, you probe only one cap at a time, if there is copper foil hooking one or more other caps in parallel, there is no isolation between them for the meter to be able to zero in on just the one unit [in a parallel circuit]. This is because the impedance [as well as the simple DC resistance] of the copper foil is very close to zero [ and of course that is exactly what the designer wants from a copper trace connecting caps in parallel].

So when you find parallel caps, you have to unsolder at least one lead [or both leads if unsoldering only one does not allow the cap to be tilted out in a crowded circuit]. You have to disconnect all but one cap so they can all be tested as individuals. Also, "tilting out" capacitors [with one lead still soldered in the board ] can damage them if the leads are very short, and most motherboard designs use very short leads for good high frequency performance.

Huck

[Huckfinn]

Re: ESR meters and the Bob Parker unit revisited

As an additional note to using the Bob Parker designed digital readout ESR meters, I am concluding from numerous tests I have done over a period of time that the meters provide an amazingly accurate peek into the future useful life of rechargeable NiCads and rechargeable NiMh batteries.

The basics of the test goes something like this: You measure the ESR of a batch of rechargeable cells that work and are currently holding charge OK. Any cells that have notably higher ESR than the majority of good cells in your batch get a permanent marker dot or such on them. Later you will notice that those guys with the mark will fail first. Quite a nifty phenomenon! An electronic crystal ball of sorts. Obviously, with time you will acquire the experience of how much ESR in ohms is a tad too high for the given size and brand of cells you are measuring for info on long term reliability.

This type of ESR "future life span" evaluation even works well with NEW disposable primary cells that test "good as new" with a battery tester, yet the ESR test indicates higher than "acceptable batch average" ESR. Yep, you guessed it, the primary new cells with higher than batch average ESR reading will poop out quite a bit before the others in the batch. As a bit of extra info, the "good as new" readings I obtained as noted above were done with a decent battery test setup that checks for battery voltage while applying a load that is reasonable and appropriate for that particular battery type.

Please keep in mind that if your particular meter uses "built in the case" capacitor discharge diodes [such as the Portugal EVB version of the meter], you will not be able to test battery ESR unless you remove the diodes first. And if you own the red readout Dick Smith version or the Anatek Blue version and are using an external diode equipped discharge harness. remember to remove [disconnect] the diodes before measuring ESR on any batteries or cells.

Huck

[Nama]

Re: ESR meters and the Bob Parker unit revisited

WOOOOO HOOOOOOOO My Blue ESR Meter is on it's way!!!!!.

I have been talking about this day for a year.

I Would like to thank everyone who guided me this far.
Even with the minimal amount of experience I have in the field
I have landed a job as the highest paid person in the small corporation I now work for. All this with no GED
I owe it all to you guys
Respect and many blessing... Jacob

[PlainBill]

Re: ESR meters and the Bob Parker unit revisited

WOOOOO HOOOOOOOO My Blue ESR Meter is on it's way!!!!!.

I have been talking about this day for a year.

I Would like to thank everyone who guided me this far.
Even with the minimal amount of experience I have in the field
I have landed a job as the highest paid person in the small corporation I now work for. All this with no GED
I owe it all to you guys
Respect and many blessing... Jacob

Well, a GED isn't everything. It seems unlikely Dr. Emmett Brown had a GED.

However, the usual progression is to start small and work your way up. Starting out as the highest paid person doesn't leave a lot of room for advancement.

And speaking of starting small, look at RusMike's ESR / Capacitance meter in this thread.

PlainBill

[Nama]

Re: ESR meters and the Bob Parker unit revisited

My esr Meter arrived today. Only problem so far is it came with no instructions.
Anyone have a copy I could get????. Thanks

Also Plainbill you are very right but I wont complain.

[PlainBill]

Re: ESR meters and the Bob Parker unit revisited

My esr Meter arrived today. Only problem so far is it came with no instructions.
Anyone have a copy I could get????. Thanks

Also Plainbill you are very right but I wont complain.

Download them from the Anatek website.

Of course I'm right!!! I'm either right or not right 100% of the time!!!

PlainBill

[Toasty]

Re: ESR meters and the Bob Parker unit revisited

Nama - there should be a link in your receipt email for the meter. It's a PDF file you can save and print.

[Nama]

Re: ESR meters and the Bob Parker unit revisited

Awesome, I got it put together this morning.
Now i need to figure out how to calibrate and use it
When i touch the prods together it reads zero. I think this is a good thing
I will real the manual again tomorrow, Thanks Bill and everyone.