Thanks Joe for doing these tests. That is my meter that was damaged, but I still have no idea how it happened. I hadn't measured any high voltages at all.
Care to link your post where you discovered that you had indeed exposed the meter to a HV source? May be good to have this information linked for future viewers.
Good idea @@joesmith-je3tq - here is the link to the EEVblog posts about how I damaged my meter with a HV source. I can't find the related YT comment right now. www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/msg1599418/#msg1599418 www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1601299/#msg1601299
I have drawn half meter arcs using just an arc welder, and similar with a 25mA current limited neon transformer, so very easy to make an arc with high enough energy in a circuit. Hard to stop this as well, unless you have very large switches with high thermal mass, and a very robust arc diverter on each contact. Probably the simplest thing to remember is not to change ranges on the meter with the probes attached to the circuit, which is probably something most people were told during basic electricity classes years ago. Now you have a very good demonstration why this was told to you, as the potential to cause this damage is there.
For reference, after cleaning the damaged area on the PCB I ran through functional testing on the meter and didn't find any issues. I really don't know how the PCB damage occurred, but it certainly looks like the result of an HV arc.
Joe, I am very curious about the next version of 121GW, maybe they'll call it 121RW (done Right). I wish there was a single web page that showed up to date problems with status; Resolved, Outstanding, etc... I recall couple of his older videos how he was splitting hairs for scratchy sound of continuity buzzer edited: *and now look at the status of his own design*. Anyhow. At least it appears firmware 2.0 has resolved delayed response of auto-ranging issues. I don't know if you had a chance of testing that firmware. I'd hate to buy this meter only to find out it fails at tasks even a cheap OWON B41T performs ot that a "new" meter just came out which is basically the same old meter without the bugs.
121GW was from the Back to the Future. I doubt they would change the name. See the following: ua-cam.com/video/f-77xulkB_U/v-deo.html Again, it's been about a year since I looked at it. Most of my recent testing was with 1.2x. I have no idea what's changed with the new firmware. I have no plans to spend more time on it until they have new hardware available. Of course, if you wanted to log data to your cell phone with the UT181A, they may actually support it with that BLE adapter I show. Again, I have no use for a cell phone and and never looked into it so I can't tell you anything about it. I don't think the 121GW is "his own design" as you state. From Dave's comments, it seems to be UEI's and I imagine they maintain the rights to it. Dave made that historical video public. I suspect it has most of the facts if this is what you are looking for.
Do you think there's hope for this meter? I see firmware 2.0 update was released and seems to improve auto ranging speed. But overall I have a feeling it's more of a beta release product. All the years of lecturing by Dave at his EEVBLOG reviewing shortcomings of other meters, when his "design" where rubber meets the road, we see it's easier said then done. Now the shoe for Dave is on the other foot. And don't get me started about the promise of open source firmware. Anyhow, I was wondering if this meter is worth considering after the update since it has a rough start.
@@tech29X I was not aware that the 121GW was ever intended to have open sourced firmware. I can tell you that is something I would never allow from a safety standpoint. I also see no value in it as I am more on the user of the meters, not the developer of them. I suspect that most people that are not directly involved with the development of products would have unrealistic ideas of the time, costs, .... involved. They did produce a product that can be purchased today so that goal was met. I don't follow the saga as the meter continues to evolve. Dave seems to get upset if I inject too much information so I cleaned up my posts and have backed down. I continue to wait for something that at least addresses what ever caused them to require customers to install a shim in their meters. It will be a substantial investment of my time to evaluate one in detail and I have no plans to consider looking at one until at least this basic problem has been addressed. I had thought this would take them a year but we are approaching two years and I have not seen any sort of schedule posted. I don't offer recommendations on this channel. If a product is worth it to an individual is entirely up to them. I don't have any ties to these companies and only offer unbiased test results which people are free to use as they like to make a more informed decision about their purchases.
@@joesmith-je3tq Joe, That answers my question, thank you very much. For example; I wasn't aware of the issue that required inserting a "shim". In the end, after 2 years of its release and reading up reviews/issues about 121GW, it still feels half baked. On the firmware issue, as a company I would never want users modify my product on principle of liability. So, I agree on that front, but it was part of the pipe dream some folks were sold on when buying into this meter at development stage. I don't know what it entails inserting a shim, I doubt that solves all issues. At this point Fluke 289 is the only decent meter with data logging. Getting very frustrating... UT181A is not has rechargeable battery, and proprietory data can't be exported to excel and requires awkward adapters to recharge, transfer data... Amost priced at a Fluke 289. CEM-9939; High burden voltage, slow display with useless bar graph. UT-61e; high burden voltage, old serial interface. Meh! OWON 41T+ High burden voltage and pure junk for input protection, but at that almost disposable price with data logging that can be exported, it might be a OK for low voltage electronics, trouble shooting parasitic drain on car battery, or repairing the occasional "ceiling fan" or sink drain :-) At least it has double wall cover that should keep sparks inside and if she blows, it's almost the price of a quality pair of replacement fuses. Anyhow, it's been fun watching and learning a thing or two from your videos. You certainly deserve much more credit. PTCs, vs MOVs, ceramic fuse vs glass fuses in "condom" shroud :P
@@tech29X You would have to show me where Dave had promised some sort of open firmware as again, I don't ever remember seeing or hearing about that. I am not suggesting that people did not want it or had high hopes of getting it but I don't think it was ever on the table. I am not sure how you came to the conclusion that the 181A's data couldn't be exported to Excel. It's the internet and I can believe that you were told that by someone who was clueless or a competitor trying to make a sale. Be careful about where you get your information. I think the cost was less than half the 289. Still this meter like most of the UNI-T products I looked at are very sensitive to fast transients. That OWEN had a lot of problems. Maybe you skipped around the video and missed them. By the time I was done, I had made a comment about not wanting to waste anymore time with it because of all the problems I found. Good luck with your search.
@@joesmith-je3tq I clearly remember you saying not wanting to waste anymore time with this; 1) My lack of understanding about nuances, technical details of your review and 2) I thought you were mostly disappointed about the piss poor input protection with the meter. 3) It had a faster updating bar graph then CEM-9939 in your review 4) It had slightly lower burden voltage than CEM-9939. 5) I liked the bluetooth/android syncing so much that I guess was fooling myself :-)
I've seen a few meters with grease. Most without. One way to improve it would be to slit the board or open the gap up even further. We have seen meters where they have run isolation slits between the switch contacts.
@@joesmith-je3tq When I saw this video couple days ago, I thought this was yet another hardware problem with 121GW, and I decided there's too much "controversy" going on about this meter. Somehow, I had gotten the impression there are problems at hardware level that no firmware update is going to make it right such as "tape eraser" test and decided to stay clear off 121GW for the time being. Maybe wait for 2xx series or firmware 3. I'm waiting to see the chaos in 121GW forum to settle down a bit.
@@joesmith-je3tq There was this guy on UA-cam, who would put bunch of electronics into a blender and shoot video while pulverizing iPhones, tablets and he would say "will it blend?" It was something like blendtech company PR stunt, demonstrating how powerful, durable their blenders are... Well, anyhow, your tests are more interesting, educational, and this is your hobby, you enjoy doing these tests, and anyone who don't like it, can move on to another channel. However, now I realize, after watching this couple time, this was not a knock on 121GW. Unfortunately, I was almost buying that meter and I shied away from it. Now, if someday I can confirm that 121GW is able to log data with timestamp for each measurement, and it's more stable I might get that, or it's almost been 2 years it's been on the market and maybe they will come up with a better product, hopefully soon!!! Brymen 525s is almost the perfect meter (for me) about 10 years old. Too bad the data sync cable is too expensive and it's not avail on Amazon. After all these years, there should be a decent meter on the market in the range of $200-250 including data logging. Some lesser meters are accomplishing this at far less cost is hard to digest and also worries me in other ways (how come cheaper knock off from Asia are making headway while the good stuff is stalling). But, that's worth another forum discussion.
That arc can be dangerous, although being limited in current. I wonder if Dave was a critic of his own multimeter after seeing that, of if he preserved his bias against cheap multimeters. This shouldn't happen on a $200 range multimeter.
I doubt there is any meter out there that would handle a test like this no matter the price. There was a part 2 to this this video and Dave made a couple of response videos as well. They may be worth your time to watch.
Well, in real life this will happen, provided that the circuit has enough energy available to make it arc. What may save the situation is that most of the grid is limited to 480V between phases (in Europe). But if there is a transient of some sort, caused by a big motor starting or stopping, that may initiate an arc. The metal vapor then will make sure it is sustained, with explosive and quite catastrophic results, unless there is a quick blow HRC fuse and a crowbar to limit the damage. Nevertheless, I'm curious to watch Dave's response. Thanks!
I've seen a lot of cooked meters on the internet. You bet that all sorts of things happen in real life. My favorite is the people that try to directly measure the outputs from their microwave oven transformers. Obviously, reading voltage in a non-voltage function and rotating the selector when the meter is connected are not wise things to be doing. And anyone working on 480V bus, I would assume would have the proper training and PPE. I think Dave's videos were on his second channel. After I saw them, I made a third video for the fun of it using a free meter from HF.
Well, I was not going as far as rotating the knob while taking a measure, although that particular multimeter was damaged that way. Misuse can circumvent protections in a lot of cases. But it scares me how many multimeters are designed. For instance, I would bet the Aneng 8008 is not CAT III rated, as the fuses are just too small to be HRC (even if they are sand filled). The creepage distance between the end caps is just to short, about 3mm. Anyway, that would be another topic in itself, I think.
UEI are not known for quality and durability. I think I broke one while checking 480 three phase motor controller on 75 hp ventilation fan. The meter lied to me and bad things happened...needless to say.... bad things happened to that meter.... with malice aforethought. I would trust the Cen-Tech over a UEI.
I still use a Cen-Tech for work. It's six years old now. Beyond loaning it out once to a person who turned the knob past the dead stop, breaking the plastic and a few blown fuses, it's been solid.
I have never looked at one. For work, if I have to troubleshoot in CAT III, I use a product made by HIOKI that I have been very happy with. I ran one of their low end DMMs through my tests and it performed very well.
My Fieldpiece SC66 clamp meter is CAT III. I purchased it new in 2001 and I'm still using the original silicone leads and I have not been gentle with it. I have used it in steam tunnels, blazing hot attic spaces and sub-freezing weather. I have never completely submerged it in water but I have used it in steady down-pouring rain. It was pretty fancy for it's day but the new models do a lot more and they are smaller. The SC66 is discontinued but I hear the current models are equally tough.
Thanks Joe for doing these tests. That is my meter that was damaged, but I still have no idea how it happened. I hadn't measured any high voltages at all.
Care to link your post where you discovered that you had indeed exposed the meter to a HV source? May be good to have this information linked for future viewers.
Good idea @@joesmith-je3tq - here is the link to the EEVblog posts about how I damaged my meter with a HV source. I can't find the related YT comment right now.
www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/msg1599418/#msg1599418
www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1601299/#msg1601299
I have drawn half meter arcs using just an arc welder, and similar with a 25mA current limited neon transformer, so very easy to make an arc with high enough energy in a circuit. Hard to stop this as well, unless you have very large switches with high thermal mass, and a very robust arc diverter on each contact. Probably the simplest thing to remember is not to change ranges on the meter with the probes attached to the circuit, which is probably something most people were told during basic electricity classes years ago. Now you have a very good demonstration why this was told to you, as the potential to cause this damage is there.
Thanks for the video and hope that nobody gets injured except the multimeter, using such high power.
Safety first.
Congrats on passing 7,000 subscribers Joe
I think that comment deserve being pinned.
I will leave both the 1 MV and 7000 J videos to PhotonicInduction. That's some big stuff he plays with.
For reference, after cleaning the damaged area on the PCB I ran through functional testing on the meter and didn't find any issues. I really don't know how the PCB damage occurred, but it certainly looks like the result of an HV arc.
Joe, I am very curious about the next version of 121GW, maybe they'll call it 121RW (done Right). I wish there was a single web page that showed up to date problems with status; Resolved, Outstanding, etc... I recall couple of his older videos how he was splitting hairs for scratchy sound of continuity buzzer edited: *and now look at the status of his own design*. Anyhow. At least it appears firmware 2.0 has resolved delayed response of auto-ranging issues. I don't know if you had a chance of testing that firmware. I'd hate to buy this meter only to find out it fails at tasks even a cheap OWON B41T performs ot that a "new" meter just came out which is basically the same old meter without the bugs.
121GW was from the Back to the Future. I doubt they would change the name. See the following: ua-cam.com/video/f-77xulkB_U/v-deo.html
Again, it's been about a year since I looked at it. Most of my recent testing was with 1.2x. I have no idea what's changed with the new firmware. I have no plans to spend more time on it until they have new hardware available.
Of course, if you wanted to log data to your cell phone with the UT181A, they may actually support it with that BLE adapter I show. Again, I have no use for a cell phone and and never looked into it so I can't tell you anything about it.
I don't think the 121GW is "his own design" as you state. From Dave's comments, it seems to be UEI's and I imagine they maintain the rights to it. Dave made that historical video public. I suspect it has most of the facts if this is what you are looking for.
Where can I find that dust protection used in the left multimeter 9:30 ?
As always great video Joe be safe!
Alex.
Thanks. I don't recommend anyone try and repeat any of the tests I show. Working at these levels could prove to be lethal.
Yeah i understand however i like repairing old valve "stuff", alot of very scary high voltages and current in there!
Certainly nothing wrong with that.
Sparkies ooooooh! lol
Nice testing as always!
Do you think there's hope for this meter? I see firmware 2.0 update was released and seems to improve auto ranging speed. But overall I have a feeling it's more of a beta release product. All the years of lecturing by Dave at his EEVBLOG reviewing shortcomings of other meters, when his "design" where rubber meets the road, we see it's easier said then done. Now the shoe for Dave is on the other foot. And don't get me started about the promise of open source firmware. Anyhow, I was wondering if this meter is worth considering after the update since it has a rough start.
Or maybe that shoe is in his mouth and he's chewing on it.
@@tech29X I was not aware that the 121GW was ever intended to have open sourced firmware. I can tell you that is something I would never allow from a safety standpoint. I also see no value in it as I am more on the user of the meters, not the developer of them.
I suspect that most people that are not directly involved with the development of products would have unrealistic ideas of the time, costs, .... involved. They did produce a product that can be purchased today so that goal was met. I don't follow the saga as the meter continues to evolve. Dave seems to get upset if I inject too much information so I cleaned up my posts and have backed down. I continue to wait for something that at least addresses what ever caused them to require customers to install a shim in their meters. It will be a substantial investment of my time to evaluate one in detail and I have no plans to consider looking at one until at least this basic problem has been addressed. I had thought this would take them a year but we are approaching two years and I have not seen any sort of schedule posted.
I don't offer recommendations on this channel. If a product is worth it to an individual is entirely up to them. I don't have any ties to these companies and only offer unbiased test results which people are free to use as they like to make a more informed decision about their purchases.
@@joesmith-je3tq Joe, That answers my question, thank you very much. For example; I wasn't aware of the issue that required inserting a "shim". In the end, after 2 years of its release and reading up reviews/issues about 121GW, it still feels half baked. On the firmware issue, as a company I would never want users modify my product on principle of liability. So, I agree on that front, but it was part of the pipe dream some folks were sold on when buying into this meter at development stage. I don't know what it entails inserting a shim, I doubt that solves all issues. At this point Fluke 289 is the only decent meter with data logging. Getting very frustrating...
UT181A is not has rechargeable battery, and proprietory data can't be exported to excel and requires awkward adapters to recharge, transfer data... Amost priced at a Fluke 289.
CEM-9939; High burden voltage, slow display with useless bar graph.
UT-61e; high burden voltage, old serial interface. Meh!
OWON 41T+ High burden voltage and pure junk for input protection, but at that almost disposable price with data logging that can be exported, it might be a OK for low voltage electronics, trouble shooting parasitic drain on car battery, or repairing the occasional "ceiling fan" or sink drain :-)
At least it has double wall cover that should keep sparks inside and if she blows, it's almost the price of a quality pair of replacement fuses.
Anyhow, it's been fun watching and learning a thing or two from your videos. You certainly deserve much more credit. PTCs, vs MOVs, ceramic fuse vs glass fuses in "condom" shroud :P
@@tech29X You would have to show me where Dave had promised some sort of open firmware as again, I don't ever remember seeing or hearing about that. I am not suggesting that people did not want it or had high hopes of getting it but I don't think it was ever on the table.
I am not sure how you came to the conclusion that the 181A's data couldn't be exported to Excel. It's the internet and I can believe that you were told that by someone who was clueless or a competitor trying to make a sale. Be careful about where you get your information. I think the cost was less than half the 289. Still this meter like most of the UNI-T products I looked at are very sensitive to fast transients.
That OWEN had a lot of problems. Maybe you skipped around the video and missed them. By the time I was done, I had made a comment about not wanting to waste anymore time with it because of all the problems I found.
Good luck with your search.
@@joesmith-je3tq I clearly remember you saying not wanting to waste anymore time with this; 1) My lack of understanding about nuances, technical details of your review and 2) I thought you were mostly disappointed about the piss poor input protection with the meter. 3) It had a faster updating bar graph then CEM-9939 in your review 4) It had slightly lower burden voltage than CEM-9939. 5) I liked the bluetooth/android syncing so much that I guess was fooling myself :-)
I wonder would it help to add Silicone DS4 to a contact to prevent that?
I've seen a few meters with grease. Most without. One way to improve it would be to slit the board or open the gap up even further. We have seen meters where they have run isolation slits between the switch contacts.
So much for that "Input protection". Lesson learned; Don't rotate the dial while probes are attached to a voltage source, particularly over 400V DC.
I doubt you would find a meter out there that would handle what I show in this video. That's a dangerous power supply that requires respect.
@@joesmith-je3tq When I saw this video couple days ago, I thought this was yet another hardware problem with 121GW, and I decided there's too much "controversy" going on about this meter. Somehow, I had gotten the impression there are problems at hardware level that no firmware update is going to make it right such as "tape eraser" test and decided to stay clear off 121GW for the time being. Maybe wait for 2xx series or firmware 3. I'm waiting to see the chaos in 121GW forum to settle down a bit.
@@joesmith-je3tq There once was an elephant named Topsy, then came along a man named Edison... www.wired.com/2008/01/dayintech-0104/
@@joesmith-je3tq There was this guy on UA-cam, who would put bunch of electronics into a blender and shoot video while pulverizing iPhones, tablets and he would say "will it blend?" It was something like blendtech company PR stunt, demonstrating how powerful, durable their blenders are... Well, anyhow, your tests are more interesting, educational, and this is your hobby, you enjoy doing these tests, and anyone who don't like it, can move on to another channel. However, now I realize, after watching this couple time, this was not a knock on 121GW. Unfortunately, I was almost buying that meter and I shied away from it. Now, if someday I can confirm that 121GW is able to log data with timestamp for each measurement, and it's more stable I might get that, or it's almost been 2 years it's been on the market and maybe they will come up with a better product, hopefully soon!!! Brymen 525s is almost the perfect meter (for me) about 10 years old. Too bad the data sync cable is too expensive and it's not avail on Amazon. After all these years, there should be a decent meter on the market in the range of $200-250 including data logging. Some lesser meters are accomplishing this at far less cost is hard to digest and also worries me in other ways (how come cheaper knock off from Asia are making headway while the good stuff is stalling). But, that's worth another forum discussion.
Will it blend; ua-cam.com/video/lAl28d6tbko/v-deo.html
That arc can be dangerous, although being limited in current. I wonder if Dave was a critic of his own multimeter after seeing that, of if he preserved his bias against cheap multimeters. This shouldn't happen on a $200 range multimeter.
I doubt there is any meter out there that would handle a test like this no matter the price. There was a part 2 to this this video and Dave made a couple of response videos as well. They may be worth your time to watch.
Well, in real life this will happen, provided that the circuit has enough energy available to make it arc. What may save the situation is that most of the grid is limited to 480V between phases (in Europe). But if there is a transient of some sort, caused by a big motor starting or stopping, that may initiate an arc. The metal vapor then will make sure it is sustained, with explosive and quite catastrophic results, unless there is a quick blow HRC fuse and a crowbar to limit the damage. Nevertheless, I'm curious to watch Dave's response. Thanks!
I've seen a lot of cooked meters on the internet. You bet that all sorts of things happen in real life. My favorite is the people that try to directly measure the outputs from their microwave oven transformers. Obviously, reading voltage in a non-voltage function and rotating the selector when the meter is connected are not wise things to be doing. And anyone working on 480V bus, I would assume would have the proper training and PPE. I think Dave's videos were on his second channel. After I saw them, I made a third video for the fun of it using a free meter from HF.
Well, I was not going as far as rotating the knob while taking a measure, although that particular multimeter was damaged that way. Misuse can circumvent protections in a lot of cases. But it scares me how many multimeters are designed. For instance, I would bet the Aneng 8008 is not CAT III rated, as the fuses are just too small to be HRC (even if they are sand filled). The creepage distance between the end caps is just to short, about 3mm. Anyway, that would be another topic in itself, I think.
I doubt most meters would meet the CAT ratings marked on the front. They make a lot of crap meters and we buy them.
Electric fence controller?
The power supply? No, it's only a KVDC. I think most fence controllers are AC and several KV.
UEI are not known for quality and durability.
I think I broke one while checking 480 three phase motor controller on 75 hp ventilation fan.
The meter lied to me and bad things happened...needless to say.... bad things happened to that meter.... with malice aforethought.
I would trust the Cen-Tech over a UEI.
I still use a Cen-Tech for work. It's six years old now. Beyond loaning it out once to a person who turned the knob past the dead stop, breaking the plastic and a few blown fuses, it's been solid.
Joe, have you ever used a Fieldpiece meter?
I've used one since 2000 and it it solid as a rock.
I have never looked at one. For work, if I have to troubleshoot in CAT III, I use a product made by HIOKI that I have been very happy with. I ran one of their low end DMMs through my tests and it performed very well.
My Fieldpiece SC66 clamp meter is CAT III.
I purchased it new in 2001 and I'm still using the original silicone leads and I have not been gentle with it.
I have used it in steam tunnels, blazing hot attic spaces and sub-freezing weather. I have never completely submerged it in water but I have used it in steady down-pouring rain. It was pretty fancy for it's day but the new models do a lot more and they are smaller.
The SC66 is discontinued but I hear the current models are equally tough.