My new "Blue" ESR tester

[budm]

Re: My new "Blue" ESR tester

I build one for experiment also, https://www.badcaps.net/forum/showth...197#post271197
By the way, the SENCORE LC-75 is more than 20 Years old, but it does its job well with 20 years old technology. Old tech does not mean it is not good, just good old SIMSON Analog VOM.

[MDOC]

Re: My new "Blue" ESR tester

Because ESR measurement doesn't need to be precise, I only gave it two displays with auto-ranging to let it measure down to 10 milliohms. So the 'experts' here consider that to be "crude" too with "poor resolution". That really demonstrates that 'expert's" level of technical knowledge.

The original ESR meter design only became publicly known when we discovered how useful it is, and I submitted it to the local electronics magazine as a construction project. A few companies started making kits for it, and it just took off. Nothing to do with me being some kind of businessman - I'm just a technician who was very surprised at the meter's popularity for such a long time.

I'd like to know two things here:
1) Are you the real Bob "Blue ESR" Parker and not just somebody masquerading his name as a nickname?
2) If so, how many frequencies does the Blue ESR use in testing across the whole value range of capacitors? One?

[MDOC]

Re: My new "Blue" ESR tester

Looking at the EXIF info on the Panasonic DMC-FZ7 camera, it was operating at ISO 400 in the picture I randomly looked at closely. It went to that setting because there wasn't a lot of light. That causes noise in the image which is more noticeable when it's such a high resolution picture. Have you tried the free Faststone image editor viewer program? It's very good for reducing the size of very big images like that (and looking at the EXIF info in the picture files).

Not familiar with Faststone, but IrfanView can do the same job and it's free. There are other programs, too... but IrfanView has a batch conversion/file-rename function which allows you to do batch operations on a set of files at once. This includes resizing.

[Bob Parker]

Re: My new "Blue" ESR tester

I'd like to know two things here:
1) Are you the real Bob "Blue ESR" Parker and not just somebody masquerading his name as a nickname?
2) If so, how many frequencies does the Blue ESR use in testing across the whole value range of capacitors? One?

Yep, you caught me out. I'm just an imposter pretending to be him. The real Bob Parker is sitting in a darkened room redesigning the Blue ESR meter PCB so that it looks acceptable to all the electronics professionals at Badcaps.

Why don't you download the kit notes for the older Dick Smith Electronics version of the ESR meter which is electrically and firmware identical to the Blue one, from the real Bob Parker's website at In it, he explains in detail how his crude pathetic obsolete poor-resolution design works. Then you can get back here and tell me off for not answering your question.


Thanks - I know about IrfanView and I'm running it too. But FastStone's also free and also does many batch operations.

[MDOC]

Re: My new "Blue" ESR tester

Yes, I've seen the article years ago--thanks for the link. Maybe I'll get back to you later about it. And you did answer my question. Don't say you didn't.

[MDOC]

Re: My new "Blue" ESR tester

Yep, you caught me out. I'm just an imposter pretending to be him. The real Bob Parker is sitting in a darkened room redesigning the Blue ESR meter PCB so that it looks acceptable to all the electronics professionals at Badcaps.

Why don't you download the kit notes for the older Dick Smith Electronics version of the ESR meter which is electrically and firmware identical to the Blue one, from the real Bob Parker's website at In it, he explains in detail how his crude pathetic obsolete poor-resolution design works. Then you can get back here and tell me off for not answering your question.


Thanks - I know about IrfanView and I'm running it too. But FastStone's also free and also does many batch operations.

OK, this is me getting back to you.
After reading the theory of operation section of your article, I opened up my "blue" and scoped it out. First, I took a bulging bad cap and measured it.


Above: I used this bulging CapXon cap: 820uF 25V


Above: ...and measured it. I didn't zero the test leads first, but the error offset didn't matter much: the real measurement value is 2.4 ohms. Here it reads 2.8 ohms.

After opening the meter, I used the waveforms shown at one of your pages:
http://members.ozemail.com.au/~bobpar/esrprob.htm
to check out the meter. During this check-out, the test leads are open.


Above: at IC2 pin 10. 1V/div, 50mS

(I'm not concerned with the probe loading effect on the microcontroller at this point because x1 or x10 probe setting didn't make any difference. This is because the test leads are open (not connected to a cap). The test procedure specifies that the test leads should be open. If a cap is connected to the test leads, then x10 should be used, because the x1 probe setting affects the circuit, thus affecting meter's readout. Probe is set to x1 during this checkout.)


Above: at IC2 pin 8. 2V/div, 0.1mS


Above: at the test leads. Scope attached to the positive lead, ground to ground. 0.2V/div 0.1mS


Above: IC2 pin 15. 2V/div, 0.1mS

This ends the check-out procedure. All tests passed. This establishes a working meter.

Now, two probes are connected to the meter pcb, one at R18 (IC2 pin 8, top scope trace) and one at Q11 collector (IC2 pin 10, bottom trace). Probes are still set to x1, test leads still open.


Above: You can see the 8uS pulses on the top trace, which gets cut off when the ramp in the bottom trace snaps to ground. 2V/div, 1V/div, 20mS


Above: another snapshot of the same thing, but this time showing both the beginning and end of the pulses. Remember, this is with open test leads. 2V/div, 1V/div, 20mS


Above: the same waveforms, except I'm using delayed sweep to highlight the last pulse and the snap to ground. Scope is set to chopped trace, that's why the dashed line in the bottom trace. 2V/div, 1V/div, 20mS, 0.1 mS delayed swp, trigger holdoff used to stabilize waveform.


Now for the remainder of this examination, the scope probe is set to x10. And, for the first time, test leads are connected to a known bad cap. No other changes to the test configuration or setup, except that this time, whenever the meter shuts off (after 3 min. idle time), the leads are zeroed after turning the meter back on. Again, two probes are connected, one at R18 (IC2 pin 8, top scope trace) and one at Q11 collector (IC2 pin 10, bottom trace).


Above: ground references for the two traces.


Above: test leads connected to the bad 820uF cap. 1V/div, 1V/div, 20mS, 0.1mS delayed swp. Top waveform pulse shows about 1.2 volt amplitude. Notice the much shorter ramp from ground before the snap. Meter reading: 15.2 ohms.


Above: known good cap (just purchased from Digi-Key), 1000uF 6.3V Panasonic cap. 1V/div, 1V/div, 20mS, 0.1mS delayed swp. This time, less than 0.2V amplitude. Meter reading: 0.7 ohms.


The meter has 0.01 ohm resolution over the 0.00 to 0.99 ohm range (that's pretty good), 0.1 ohm resolution over 1.0-9.9 ohm range, 1 ohm resolution over 10-99 ohm range. For all practical capacitor test purposes, you don't need 0.01 ohm resolution for the last two ranges. A two-digit display is all you need from a practical standpoint, and this saves money.

This meter includes a battery power design improvement that allows auto shut down when the voltage reaches 5.6V instead of 7V. This means longer battery life.

The frequency of the pulses is 2kHz, but meter measurements are not based on frequency. It's based on both the amplitude and the number of 8uS pulses.


Now, a little bit of criticism, if I may.

The 9V battery is hard to remove from its tight compartment, even with a small screwdriver. A pull strap will help.

The meter readings can get flaky because of the connectivity of the test lead tips to the cap under test. However, the flakiness is not too great a problem in practical terms. The tips I used are Pomona test clips made of brass. The problem might be mitigated by using gold contacts instead.

Take a look at the snippet below from the page at:

in the "battery warning setup" section, where a little circuit is shown for supplying a variable DC power for calibrating the low battery warning indication. But superimposed onto this circuit is a picture image partially obscuring the circuit. I've seen this before years ago, yet this is not fixed.


The end

[Bob Parker]

Re: My new "Blue" ESR tester

Hi MDOC, I'm sending you a PM.

[MDOC]

Re: My new "Blue" ESR tester

Forgot to add a couple of photos in my haste to send off the previous post.


Scope test setup of the ESR meter with the bad cap (CapXon) connected. Dispay reads 2.6 ohms.


Testing with the good cap (Panasonic) connected. Dispay reads 0.4 ohms.

[budm]

Re: My new "Blue" ESR tester

So MDOC, are you using this meter for your cap verification?

[MDOC]

Re: My new "Blue" ESR tester

So MDOC, are you using this meter for your cap verification?

What do you mean by cap verification? Stand-alone, out of circuit cap tests?

[MDOC]

Re: My new "Blue" ESR tester

Testing with the good cap (Panasonic) connected. Dispay reads 0.4 ohms.

This should read "Display reads 0.04 ohms." (!)

[budm]

Re: My new "Blue" ESR tester

I mean to see if the capacitance tested good but the ESR is high which caused the circuit not to work. A lot of newbie will say that the cap look good, capacitance read OK, but the circuit still does not work, I always tell them to check the ESR next which they will have to invest in an ESR meter or just change the cap.
So far, will you recommend owning this Blue ESR meter?

[MDOC]

Re: My new "Blue" ESR tester

I mean to see if the capacitance tested good but the ESR is high which caused the circuit not to work. A lot of newbie will say that the cap look good, capacitance read OK, but the circuit still does not work, I always tell them to check the ESR next which they will have to invest in an ESR meter or just change the cap.
So far, will you recommend owning this Blue ESR meter?

You would be correct in the statement about caps testing good in capacitance but bad in ESR. The Blue pulsing design allows checking the caps in the circuit without having to take them off the board. I already found two bad caps on my motherboard.

So, yes, I would... despite the problems I identified. This Blue ESR seems to be the only one that contains a microcontroller.

[Kiriakos GR]

Re: My new "Blue" ESR tester

Yep, a very crude design with hopeless resolution. You got it 100% correct. DO NOT touch the Blue ESR meters.

I will not, I will touch instead the DER EE DE-5000.
The bored TV repair man could play with lesser accurate devices, like yours.

[twbranch]

Re: My new "Blue" ESR tester

I am a professional Avionics Tech with 20 years experience. I own the Blue and would not waste my money on the junk you keep mentioning. You, my friend, need to build something better if you think you can. I doubt you can judging from the fact you have not examined the tester the way MDOC did. I have more expensive ESRs on the shelf now collecting dust that have not been calibrated in a few years just because they are broken pos. I do not want to waste my money on the proprietary parts to repair something when I can use the Blue.

[tom66]

Re: My new "Blue" ESR tester

Don't listen to Kiriakos. He was banned from eevblog for pissing everyone else off.

[Bob Parker]

Re: My new "Blue" ESR tester

I am a professional Avionics Tech with 20 years experience. I own the Blue and would not waste my money on the junk you keep mentioning. You, my friend, need to build something better if you think you can. I doubt you can judging from the fact you have not examined the tester the way MDOC did. I have more expensive ESRs on the shelf now collecting dust that have not been calibrated in a few years just because they are broken pos. I do not want to waste my money on the proprietary parts to repair something when I can use the Blue.

Thanks for your positive words about the Blue ESR meter - much appreciated.

I can't see the posting(s) you're apparently replying to and I've got no intention of removing those three "ESR Meter Experts" from my ignore list.

Cheers,
Bob

[MDOC]

Re: My new "Blue" ESR tester

I am a professional Avionics Tech with 20 years experience. I own the Blue and would not waste my money on the junk you keep mentioning. You, my friend, need to build something better if you think you can. I doubt you can judging from the fact you have not examined the tester the way MDOC did. I have more expensive ESRs on the shelf now collecting dust that have not been calibrated in a few years just because they are broken pos. I do not want to waste my money on the proprietary parts to repair something when I can use the Blue.

twbranch, kudos.

[twbranch]

Re: My new "Blue" ESR tester

MDOC, I appreciate the time you put into that analysis. Kudos to you!

[MDOC]

Re: My new "Blue" ESR tester

You're welcome, everybody!