121GW EEVBlog Multimeter Megohm Resistance Problem

[@SianaGearz]

Well i'm happy that you're alive again

[@ralphralph8832]

Just checked 1M - 10MOhm with my DIY resistance decade. 121GW Version 2.02. Every value well in 1% spec of my decade resistors. Also compared with my Keithley 2000 (6.5 digits, 4 wire). Also measured single resistor values: 1M +/-0.01% gives constant reading 0.9999M after ~5 seconds 10M +/- 0.01% gives constant reading 10.008M after ~5 seconds 18,2°C in my cold lab :-) So every value nearly spot on and well within spec of 121GW. Maybe a Version Problem?

[@KainkaLabs]

Did you only have 1Megohm and 10 Megohm resistors for checking or also the values in between? With those values (1/10M) I also had no accuracy problem. It were the values 5,6 Megohm, 6.8 Megohms and 8.2 Megohms where I found that the accuracy was approaching the limit of the given specs. I will also recheck after a version update.

[@ralphralph8832]

@@KainkaLabs On my resistance decade I checked every value from 1M to 10M in 1M steps. Also I checked 5M6 and 6M8 and some values inbetween. All readings on the 121GW well within the 1% range of my decade. The 1M and the 10M were extra resistors with low tolerance.

[@KainkaLabs]

OK. Then it is probably an unlucky combination of tolerances running in the same direction with my unit. Nevertheless I still wonder about a different explanation due to the "nonlinear" behaviour of the tolerance. I still have to upgrade the firmware to the latest version and see if anything changes.

[@injoelsgarage3934]

Hi Rodger, my GW121 has firmware version 2.04, wondering if updating to ver 2.04 would make a difference? Joel

[@DIY-valvular]

Now Dave Jones will make one of his ironic teardowns about your LCR box in revenge! :-))))

[@KainkaLabs]

There he will find of course that the lowest decade of the inductors (10nH...100nH) is useless because of the parasitic series inductance of the switches and the cables. Of course this video was in no way a criticism about the 121GW. I still find it by far the best multimeter in it´s price range. And didn´t it become even cheaper some time after the first batches were sold?

[@DIY-valvular]

​@@KainkaLabs I was kidding. You know, Dave has an acid sense of humor and I wanted to joke about that. Thank you for your answer, Roger.

[@Danny-wv8ec]

@@DIY-valvular I'm here from the latest EEV blog video, Dave really liked the LCR box construction but didn't put it through it's paces. I totally get what you mean about his acid sense of humor😀. Danny from Lebanon.

[@DavidLindes]

@@DIY-valvular I wonder if Dave has seen this. It would be interesting to see him try replicating this, and/or hearing what he has to say about it.

[@DIY-valvular]

@@DavidLindes Hey David. Maybe Dave saw Kainka's comment about the dmm he sale or maybe not. The fact is that Dave has a remarkable sense of humor and both eevblog dmm and Kainka decade box are great instruments actually (if my incomings improves, difficult thing in argentinean economy) I will be happy to buy both instruments!. One point in favor of Kainka's kit is that it's a product of his own creation.

[@DavidLindes]

Interesting! A bit of hopefully-constructive feedback: some of your text overlays (e.g. the one at 4:24) are exceedingly difficult to actually read (at least on a small screen, but even on something of moderate size)... perhaps you could make them stand out a bit more in the future. I might suggest white with black drop shadow instead of the... is it grey on white?? Even full black on white might help , but with all the white silkscreen right behind things, it might still be a challenge. Yellow on black, then, maybe? And/or just bigger text. Thanks for considering it. :)

[@KainkaLabs]

Hm. I always thought that the readability is quite good. When I edit the videos the text stands out extremely clear on my 19"-LCD. The text-colour is 100% black (or 100% white when superimposed on a dark background).

[@GameProgrammer79]

it looks a nice multimeter but marred by issues and accuracy problems

[@KainkaLabs]

I disagree. For me it´s the best multimeter in it´s class. If you read the comments you will find that it is still within specs and other people did find more exact measurements in the high Megohm range with their 121GW.

[@MetawolfTV]

Might get one soon

[@tacticalsavage]

dave and his f. ego...and the results...thanks for the video.

[@KainkaLabs]

As others have already written: It´s still within specs :-) And I am still quite happy with the 121GW.

[@Jonas_Meyer]

Wouldn't call it a problem if its still in spec.

[@KainkaLabs]

You are right of course. What I was wondering about is that the error is not constant but varies over the range.

[@lordelectron6591]

I came from the eevblog