Handheld meter robustness testing

[oh2hyt]

I read whole thread last week. And originally youtube suggested your videos to me.

Nice work, keep going - without pressure.

[joeqsmith]

Thanks and glad you are enjoying them.

YouTube gives you all sorts of metrics.  One is the source of the traffic.  By far the highest is YouTube recommended which is about 40%.  YouTube search is very high as well.  External is about 6%, of which Google search makes up about 40% and  EEVBLOG is about 6%.   A little strange as this thread is really about the only place I post about it.   

If 60 minutes of talking about wire was not enough, someone had asked me about the shunts having an offset after they were heated.  In the last video, I never let the meter cool enough which may have led to some confusion.  I was planning a very quick video on this as time permits.

[joeqsmith]

Using my MIG welder on the UNI-T UT61E.     

[joeqsmith]

Using the oxy acetylene torch on my UT61E.  Time to machine up some parts.

[joeqsmith]

Enjoy

[BroMarduk]

So, Joe, has anyone from UNI-T contacted you for a place on the engineering team?   

[joeqsmith]

So, Joe, has anyone from UNI-T contacted you for a place on the engineering team?

Now that would be funny.  Actually, no one from any company (manufacturer,  designer or distributor) has ever contacted me about any of my multimeter videos beyond the few responses I have received to questions I have asked. 

[joeqsmith]

Looking at some of the meters burden voltage in the 1uA range.

https://www.youtube.com/watch?v=7ivcPLOOACg&feature=youtu.be

[SeanB]

Know that the new EEvblog meter will be given a very thorough test in that lab. I think though that those shunts might be a hard thing to make in bulk cheaply, unless you made a custom machine that took a precut length of material, used a welder to do an automated join both sides to a solderable material, then finished the join to an acceptable dimension, and then bent it appropriately, followed by another jig that allowed automatic grinding up to the required value. following that a journey through a polishing machine to get them shiny again and then installed.

Do like that PTFE housing there, very nice looking, and probably costs as much as the BOM of the meter alone.

[joeqsmith]

I used silver solder with a torch.  The two ends I machined from brass.  I do use a lot of Teflon in my projects.   

Want to talk about cost, what's fully burdened engineering time cost now days?  Spread that across one meter....  This one UT61E is a goldmine!    IMO, it's a better meter functionally now but it's still poor.  That 1K shunt could be improved and still no temperature and no AC+DC and.....  It's a very poor investment from cost standpoint but for the few people who watch my videos, it may be worth it in entertainment.     

I have had a few people post about making a kit, to me its a really bad idea but sounds like that would be something you may be interested in pursing. Drop some Evanohm in there.
 
http://www.goodfellow.com/catalogue/GFCat4J.php?ewd_token=M5lGZEHfcEMRY5GH6lqFqvdENYjdCH&n=owTbQj1aBHgd3f2gHi6hCcK12EZeOa

[joeqsmith]

The remainder of the meters I have that support the uA range are checked.  Also someone had asked about running them at a higher current.   I also tossed in the Fluke 101 because everyone knows it can't read current. 

[joeqsmith]

The TPI looking at the drop across the UT181A, the Brymen looking at the drop of the UT61ELB.   Hope to have the video on-line in a few hours.

[joeqsmith]

Enjoy

[joeqsmith]

I still have not pulled the trigger on a Gossen to run.  These are the three I am considering for my 2000 follower review.  Functionally none of them are as good a fit for me as the Brymen BM869s or the UNI-T UT181A.     

M205A $243, 6000 count, basic meter
If I go this route, it’s like buying the low end HIOKI just to see how they do.   
http://www.tequipment.net/Gossen-Metrawatt/M205A/Multimeters/?b=y&v=7758
 
M248A, $732, 310000 count
It can’t measure conductance, can’t measure two temperature inputs, has no bar graph but they offer a BT version. 
http://www.tequipment.net/Gossen-Metrawatt/M248A/Multimeters/?search=true

M249A, $1053, 60000 count
Measures conductance and it can measure power.  Dave did a review of it and it looked like shit on the inside.  Some tacked down axial resistor.  I was not impressed.   I asked Gossen if this was a production meter as they link Dave's video.  No response but Howardlong provided the information below. 

I am leaning towards the Ultra being a better fit and something I would actually use.  If you own one of the Ultra, I would be very interested in hearing how you like it.  Any problems? 

Gossen provides a link to your video and I asked them if the meter was a proto or if the tacked down resistor was current production.  I have not heard back.  Did you ever find out?

I guess it is no more and they had a re-spin, this is mine, purchased about 18 months ago.

Full 20MP Hi-res image here

Thanks for the picture.  Looks good.  After 18 months, any complaints with it?  The only bad comment I have seen was on Dave's video where the person shorted the current inputs to the mains and damaged the meter.

I hardly ever use it. Being an Energy meter with simultaneous I and V, I bought it on the premise I'd be able to use it for measuring microcontroller power in and out of low power modes, but I'm afraid I've found it's useless for that. The relatively slow auto-ranging means the burden voltage changes so it has too much effect on the DUT. I really should've thought that through!

I am sure it's good for higher power simultaneous I and V.

The other thing is that there is a physical prevention of you having probes plugged in and/or moving the dial in certain modes with probes plugged in. I find it a bit of an irritation, a bit nanny state if you like, I'd rather it beeped at me instead.

The ground probe is stackable at the meter end which means it protrudes out. Now while a stackable probe is great in some circumstances, it means it won't fit into its purpose made case with it plugged in. I like to have a meter ready to go, probes connected, you can't do that with this meter if you use the carrying case.

I find using the meter itself a bit daunting, the UI isn't too obvious to me, I find I have to refer to the manual. This may also be down to lack of use though!

Despite being soft power on, the two AA cells are the same ones supplied with the meter 18+ months ago, so that works OK.

I would say that it does look the part when you get it out on the bench!

With apoogies, this is off topic.

[joeqsmith]

I was looking to improve the burden voltage for the UT61E's mA ranges. 

[joeqsmith]

Painted the little PCB case I made for the powered shunt.  Used some rub on lettering.  Hit it with some of the wife's clear nail polish and things went to down hill.  I've letter like this countless times.  Maybe Revlon changed their formula.      I didn't show it doing any AC like I did with the UT61E mods.  So here's a shot comparing it with the EEVBLOG BM235 meter. 

[bitseeker]

Unfortunate situation with the lettering there. I've had clear nail polish dissolve cured paint before. Hard to know what to expect until the chemicals meet.

[joeqsmith]

The last bottle my wife picked up for me was marked 3994 Clear 76. The contents are starting to get pretty thick and turning yellow (I had a VIC20 when she bought it).  It lists the contents on the bottle.  Females play with some pretty bad chemicals.   The new stuff was a 771 Clear and has a peal off sticker I just found on the underside listing the contents.  New formula. 

I used to just spray them with clear coat (enamel to match the paint) but like the nail polish for quick jobs.  Looks like it's back to enamel spray. 

I need to write Revlon a letter explaining I am a dissatisfied customer 

[bitseeker]

I need to write Revlon a letter explaining I am a dissatisfied customer

That'd be a hoot

[joeqsmith]

SIBA branded fuses sold by UXCELL. 

[Vgkid]

That was a nice video, thanks.
I have a set of those Cross pens/pencils.

[bitseeker]

SIBA branded fuses sold by UXCELL. 

I've always been leery of fuses from who-knows-where. Good to see some tests that quantify it.

[joeqsmith]

Even if we ignore the whole safety side of it, it would be interesting to have a few meters that use this fuse and see if there are cases you could damage the meter with a counterfeit where it would have normally survived.  The problem with that is the counterfeit fuse supplier's may not have very good quality control (why would they?) and the trip time/current could vary a fair amount. 

[bitseeker]

Yeah, you'd probably have to test a fair number of them to get any kind of statistical significance. Sounds expensive, but interesting. It would also be interesting to see how accurate, relative to their spec sheet, and consistent the genuine ones are.

One potentially good thing about the fake one you tested was the lower resistance.

[joeqsmith]

There was a fairly good drop in the burden voltage on the UT61E when I changed to the 20A fuse.  But consider I had beefed up the shunt, connectors and surrounding traces to handle the additional current.   So I will give you that putting on of these counterfeits in say the UT61E's 500mA it would further improve the burden and I believe the diodes would handle the added current in that one case.  However they are not using 4000 series diodes and I have those large TVSs in there now.   I wouldn't attempt it on any meter I cared about without looking at the circuit to make sure it could handle it. 

A friend of mine gave me his old RadioShack meter today.  It's catalog number 22-813.   On the back it states "Custom manufactured in China for RadioShack Corporation".   This in one of those really bad designs where they share the V/ohms with the mA.  One wrong turn of the knob and at best you pop a fuse.  Worse, the mA is between the ohms and volts.      Oh yea, it's also unfused for the 10A input.  I wonder if it's like that crappy Tekpower analog meter where the fuse is in-line with the input, so once blown nothing works.   

I am still looking at Gossen.  I have been trying to get some questions answered by them and downloaded their LabVIEW drivers.  The software looks fairly straight forward but I have been unable to locate any sort of programmers manual.  Maybe Dave will make the 121GW available soon.