EEVBlog 121GW Discussion thread

[Brumby]

Somehow I had a feeling Gnif might have known his way around the database.   

Manually tweaking the database is his preferred method for everything, he's a nerd 

I like his approach.    

[dcac]

Thanks for the update - it wasn’t really anything urgent I needed to search for in that thread. So I'll just wait until it gets back online.

[dcac]

I see you guys are working on it as we speak - just a note the restored thread does not have the 'pinned' status (yet).

[coromonadalix]

now pinned 

[oliv3r]

Hey all,

I seem to be stuck on the IAP- 'down' screen for some 20 minutes now, trying to update from 1.58 (beta) to 2.04. Any reason why? or should I just restart it ...

[Scottjd]

https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-firmware-details/msg2828400/#msg2828400

If you downloaded the firmware and its in a zip package, you have to unzip/uncompress the file first.
Its important to make sure the new firmware file on the SD card is named “EEVBlog.bin” with no spaces in the file name or the meter might hang and just display down.
If the batteries are old then you might want to make sure you have a fresh set of batteries installed before running the firmware update. I think I’ve read the newer firmware will check the battery level first, but i’m not sure about that.

1. Turn the meter off then hold down MEM and HOLD while turning on the meter.  You will see IAP on the display.
2. Press the “SETUP” button and it will display “DOWN / DOUUN” and after 5 seconds the meter bar should start rising from the left to right.
3. Once the bar hits the end the meter will restart displaying the new version of firmware installed.
This whole process after it displays “DOWN / DOUUN” shouldn’t take more then 15 seconds.

Someday, maybe someday they will add a timeout to the firmware update menu so it will error out after say 3 to 5 minutes?

[oliv3r]

https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-firmware-details/msg2828400/#msg2828400

If you downloaded the firmware and its in a zip package, you have to unzip/uncompress the file first.
...

Thanks for that, (of course) I did all that, but the problem was far simpler. I forgot to move the SD card into the meter

Someday, maybe someday they will add a timeout to the firmware update menu so it will error out after say 3 to 5 minutes?

Which would have been super helpful in my case. But I think this is the built-in IAP code, so bootloader change, and remotely (via SD) not update-able? (update-able fine with st-link of course)

[Brumby]

If I were Dave, I'd be rather interested to see what the actual cause of the failure was.......

Looks like the post was removed.

Yes, it has been.

[J-R]

Is there a discussion about the fact the 121GW is 99,999 count when in calibration mode?

[dcac]

Is there a discussion about the fact the 121GW is 99,999 count when in calibration mode?

Not that I can recall - other than it’s been mentioned Agilent U1282 which is a 60,000 count meter also uses the HY3131.

And then there's this: https://reference.digilentinc.com/reference/add-ons/dmm-shield/reference-manual which is also based on HY3131 and claims to be a 5 1/2 digit meter.

But HY3131 is only rated for 50,000 count at a specified sample rate, accuracy and linearity in the datasheet. But it is in fact a 24bit ADC so theoretically you could get 2^23 or 8388608 count - in a perfect world that is.

But I noticed that too with 121gw in calibration mode that many modes/ranges acts as a 99,999 count meter. But I think the 5M and 50M ohms ranges only reaches 67,000 or something like that.

[J-R]

Ran a bunch of tests and was surprised that specifically all the DCV & DCmV ranges were quite accurate all the way up, for example 9.87654V on the calibrated supply was 9.8764V on the 121GW.  Past about 2 9's on the display and things were a bit off, however.

mA and A gained the extra headroom but the accuracy wasn't quite worth it.  Capacitance and resistance were spotty as well.  Some useful information could possibly be found under certain conditions.

Pushed 990V through it for about a minute with no issues.  It still beeped constantly despite happily displaying the correct voltage...

[skysurf76]

Anyone have any idea how often Dave gets shipments of 121GWs?  I'm wanting to pick up another but they are currently out of stock.

[Brumby]

From what Dave has said recently, I don't think even he can answer that at the moment.  It appears there are supply issues with some of the components - which would make it difficult for even the manufacturer to give a date.

[skysurf76]

I figured that might be the case. Thanks Brumby.