Bob Parker ESR Meters

[Bob Parker]

Re: Bob Parker ESR Meters

Do I get one for free???

A protector or an ESR meter? Unfortunately I don't have any of either of those things.

PS: I'm not a guru - just a technician who needed my own ESR meter so bad that I had to design one.

[Topcat]

Re: Bob Parker ESR Meters

Do I get one for free???

[Bob Parker]

Re: Bob Parker ESR Meters

Thanks for the info Bob P, saw on your site the link to the Anatek DSESRSavr

http://www.anatekcorp.com/testequipment/dsesrsavr.htm

How does that thing work? To me it looked like just two big diodes and two resisitors plus the other two gigantic things I don't know what they are (capacitors?)

So I thought I could build something similar myself...

It's a patented device. I've tried it and it protects the meter very well. However it slightly reduces the accuracy and increases the test lead resistance, and takes up space in the case. I'm not sure if it will fit in the Mk2 meter case. I'd suggest that you contact Anatek and buy one if it will fit; they don't cost very much.

[Per Hansson]

Re: Bob Parker ESR Meters

Thanks for the info Bob P, saw on your site the link to the Anatek DSESRSavr

http://www.anatekcorp.com/testequipment/dsesrsavr.htm

How does that thing work? To me it looked like just two big diodes and two resisitors plus the other two gigantic things I don't know what they are (capacitors?)

So I thought I could build something similar myself...

[Bob Parker]

Re: Bob Parker ESR Meters

Just a thought to my post above, what if I also put 5w resistors after the diodes; should not that make the capacitor dissipate it's charge slowly and nicley while at the same time protecting the ESR meter?

Because the diode only approach sounds a bit dangerous if I connect it to a really big charged cap, I think bad stuff will happen

The meter can only zero out test lead resistance of 0.99 ohms or less. This is a function of the design. You can't put resistors in series with the test leads. If you are really worried about connecting it to charged high voltage capacitors, you could put an inline fast-acting fuse in one of the test leads. The combined resistance of the fuse and test leads will need to be less than 0.99 ohms, so the choice of fuse will be more determined by that limitation than its current rating.

When I designed the meter, I never imagined that so many people would connect it to big charged high voltage capacitors, so I didn't allow for this to happen and only gave it protection up to about 50V.

[Bob Parker]

Re: Bob Parker ESR Meters

Assembled my MK2 ESR meter now, it's working fine, right at the first try also

Included some pics of it almost complete...

The test probes as was already said above do not work too well though, gonna buy a new pair at Elfa, need a pair for my multimeter anyway because they have also given up :/

Will also buy 2x 1N5404 diodes to put on the testleads to protect the meter from charged caps... Anything else I could add to make it even more safe?

And thanks Bob.P for joining the forum and designing the ESR meter for us crazy fools

Hi Per,
You've built it very well. Congratulations that now you've got a Mk2 ESR meter!

In fact the crazy fool I designed the ESR for was ME. I thought it was so useful that I'd make the design public. Of course I'm very happy that lots of other crazy fools (and some sensible people!) are using it too.

So far I have not heard of anyone damaging an ESR meter after installing the big protection diodes. But if you connect it to a big charged high voltage capacitor, it will burn the tips off your new probes.

[Per Hansson]

Re: Bob Parker ESR Meters

Just a thought to my post above, what if I also put 5w resistors after the diodes; should not that make the capacitor dissipate it's charge slowly and nicley while at the same time protecting the ESR meter?

Because the diode only approach sounds a bit dangerous if I connect it to a really big charged cap, I think bad stuff will happen

[Per Hansson]

Re: Bob Parker ESR Meters

Assembled my MK2 ESR meter now, it's working fine, right at the first try also

Included some pics of it almost complete...

The test probes as was already said above do not work too well though, gonna buy a new pair at Elfa, need a pair for my multimeter anyway because they have also given up :/

Will also buy 2x 1N5404 diodes to put on the testleads to protect the meter from charged caps... Anything else I could add to make it even more safe?

And thanks Bob.P for joining the forum and designing the ESR meter for us crazy fools

[starfury1]

Re: Bob Parker ESR Meters

ok just had a look with the supplied leads yeah bit wobbly and contact on the probs is not great either
so this would defiantly apply as a procedure to do as part of the construction process me thinks
if you are going to use the supplied leads

Just beware as pointed out above some cleaning solvents will destroy plastic as soon as look at it,
other stuff will break it down over time so use the recommend is my advise.

Now excuse me while I go myself over the head for not thinking of this when I first posted

Cheers all

gdement I've PMed you please respond when you can thank you

[starfury1]

Re: Bob Parker ESR Meters

Wow

I am not here and look whats happened!

Welcome Bob and thank you for your input

RE the quality post yeah I was scratching my head on that one...

But thought I would post it, since they mentioned it
For others too form there own opinion....

As to the probe yeah doh! sometimes you miss the obvious thing to do.

Just lately the quality of cheap stuff has been not good and why I recommended better quality probes or plugs.

I thought later after id posted
I should have made it clear about the meter and contact resistance.

gdement don't worry mate we all start somewhere and this is why we have forums to help each other and learn so thanks for your posts and input.

As to DS yeah ....not sure if I put this in the post, maybe a pm but its become somewhat of a supermarket....and that was my suspicion..."'to drop all kits"

The range of parts and kits has been growing less and less as the years roll on

We still have 2 that cater to the electronics enthusiasts in Australia.
( and that was my other thought Bob although I didn't mention it)

Cheers all

[Bob Parker]

Re: Bob Parker ESR Meters

All is well! I tweaked the tension inthe plugs, wire brushed the plugs ans tips, and cleaned it all with brake cleaner. Worke perfect.

Excellent! Just be careful with that brake cleaner ... the stuff I've used attacks most plastics in a big way.

[Spacedye69]

Re: Bob Parker ESR Meters

All is well! I tweaked the tension inthe plugs, wire brushed the plugs ans tips, and cleaned it all with brake cleaner. Worke perfect.

[tazwegion]

Re: Silicone Chip's ESR meter kit @ DSE (AUS)

"Low interest"....? The guy's a fool. It's simply because DSE's management has made the executive decision to stop production of all kits and they're trying to get them all out the door so they can use the space for more phone answering machines, MP3 players and vacuum cleaners.
There's still a lot of interest in ESR meters!!

Sadly, since Dick Smith sold off his interests in the electronics store chain they seem to have gradually moved away from the electronics professional/enthusiast/hobbyist client focus to that of general consumerism, it's really quite a shame as I've been a regular customer since 1983 and have found myself having to source more and more components from alternative sources

Additionally, a once well padded technical/data section in the catalogues has been put on a serious diet

* applauds forum members on completing their kits... looks ashamedly at unfinished project *

[Bob Parker]

Re: EVB ESR Meter (Bob Parker Design)

Turns out the diagnostic won't run unless you hold the button on the FIRST try. After that it won't enter diag mode. Since I wasn't holding the wires together perfectly enough, it looked like the diagnostic wasn't running but I eventually realized it worked fine. I got the expected .8.8 result. I see no reason why the diagnostic shouldn't work on subsequent attempts to hold the button - that's one change I'd suggest if Mr. Parker ever decides to reprogram it.

The function of the button when the power is already on is to zero the meter if the probes are shorted (< 1 ohm resistance) or turn the meter off (=> 1 ohm). It made more sense for the microcontroller to watch for the button being pushed for 5 seconds only at initial power-up, not in the middle of normal operation. The self-test function is something you should never need once the meter's built and working, and I didn't want people accidentally triggering it. That's why I did it that way.

Glad you got the meter working OK and I hope it will be very useful.

[Galvanized]

Re: Bob Parker ESR Meters

Spacedye69, here is what kc8adu was referring too http://www.caig.com/ I use both the Deoxit and Pro-Gold (no longer avalible in the nail polish like bottle). If just a touch is used on batteries their life is extended to a noticable degree, cell phones, digi-cams, any dry cells and I use it on test leads also. Very little goes a long way.

Hi Bob Parker *tips hat*.

[gdement]

Re: EVB ESR Meter (Bob Parker Design)

My meter is all closed up now and works fine. These little single-layer boards seem to give me trouble - I burned some of the pads and had to patch them with wire. I've only soldered on a little board like this once before, and that was on one of those generic Radio Shack PCB's you can buy for $1.79. It's been long enough since then that I was out of practice (not that I got much practice even then).

Kind of embarrassing to show all my mistakes, but maybe I hit some caveats that others may benefit from reading.
I'm disappointed with the flaws, but I always have to do something 2-3 times before I get it right. If I were to build one of these again it would come out better I'm sure.

=====

I noticed about 3 or 4 ruined pads along the way, and repaired them with wire.

I used a machine pin socket on the 28-pin, but only because I happened to have one. I wanted to use machined 16 and 18-pin sockets for the IC's, but I didn't have the right sizes.

I used a HeathKit variable DC power supply which I recently bought from a Goodwill store (lucky find). It has a built in ammeter so that was convenient for the first test. Unfortunately, it also has a built in current limiter, and in my inexperience I had it set too low. My first attempts to start the meter showed no current draw and nonexistent IC voltages, so I started tracing the circuit to find the problem. There wasn't one - after I tried raising the limit it started right up. Voltages were fine, so I installed the chips.

At this point I didn't have the button connected yet, so I was holding the wires together to start the diagnostic. It didn't seem to work, so again I started tracing the circuit. Turns out the diagnostic won't run unless you hold the button on the FIRST try. After that it won't enter diag mode. Since I wasn't holding the wires together perfectly enough, it looked like the diagnostic wasn't running but I eventually realized it worked fine. I got the expected .8.8 result. I see no reason why the diagnostic shouldn't work on subsequent attempts to hold the button - that's one change I'd suggest if Mr. Parker ever decides to reprogram it.

Fast forward a bit, I was starting to play with the probes and noticed how hard it was to get a stable reading. The meter shut off whenever I tried to zero it, because the resistance was too high. The jacks were fine though, as the meter worked very well with items stuck into the jacks directly. I ended up soldering directly to the PCB, but I'm not sure that made much difference. I've found that I just have to squeeze the probes against each other pretty hard before zeroing them. When I measure a cap, I get good readings as long as I stab the probes into the solder with some pressure. That's understandable considering the fine measurements involved.

As far as strain relief (which I mentioned in my earlier post), I ended up not doing much about it. At first I tried tying the wires in a knot behind the panel, but there wasn't really enough room to squeeze that in. I accidentally wrapped one wire around the other when I soldered them, so they are somewhat crossed on each other anyhow. They seem to snag on each other more than the PCB, so I'm not worried unless the probes get yanked pretty hard.

My final error (last one, I promise) was with the red filter installation. I used superglue to install it, and it started to squeeze out on the top cover. I grabbed the first thing I could find to wipe up the mess before it dried, and that thing was alcohol. It wiped out the cover markings pretty easily, so I now have a "E--__ter". Oh well, it works just the same no matter how it looks. I've already diagnosed bad surface mount caps on a board that I otherwise would have only been able to guess about. Great tool.

[Spacedye69]

Re: EVB ESR Meter (Bob Parker Design)

Thats exactly what I am going to do. I did notice the contact area on the male ends as recieved is a little small. A few tweaks with a screwdriver and they will be better than new.

[kc8adu]

Re: EVB ESR Meter (Bob Parker Design)

on the bananna jack issues.
i retension the plug(male) and apply deoxit.
radioshack discontinued the pens and i loaded up on them.
i find most of the inaccuracy reported in this unit is high contact resistance in test leads and jack/plug.
all 6 of mine have been excellent.
care must be taken during calibration though.

[Bob Parker]

Re: Silicone Chip's ESR meter kit @ DSE (AUS)

dse going the way of radioshack here?
should be renamed cellphoneshack!

Radio Shack had a chain of stores here called Tandy Electronics. DSE bought that chain and combined it with their existing operation. Maybe that's where their present consumer-electronics-obsessed management got the idea from that they should drop all kits. I have no doubt that it won't be long before they stop selling components too.
There are two hobbyist companies down here who are going to be ecstatic that DSE is out of the kits business. Lots more sales for them! I'm hoping that one of them will take over making the ESR meter kits.

[kc8adu]

Re: Silicone Chip's ESR meter kit @ DSE (AUS)

"Low interest"....? The guy's a fool. It's simply because DSE's management has made the executive decision to stop production of all kits and they're trying to get them all out the door so they can use the space for more phone answering machines, MP3 players and vacuum cleaners.
There's still a lot of interest in ESR meters!!

dse going the way of radioshack here?
should be renamed cellphoneshack!