Modified Kusuntest ZT102 / AN8002
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- Опубликовано: 6 сен 2024
- Someone had asked about using a MOV to add some protection to these low cost meters. In this video, I take a look at modifying the ZT102.
The latest spreadsheet show the data I have collected may be found here:
docs.google.co...
The FAQ may be found here:
docs.google.co...
"Its blown all to hell!" - awesome video, Joe. Thanks for your efforts.
Your mods are amazing, it's very interesting to watch your videos.
Thanks. Glad you enjoyed it and found it of interest.
Love using the defunct parts to provide an access to the already present range pad.
Once again Joe a excellent video. All multimeters manufacturers should seek your advice I would trust any multimeter after you have put it though it your testing. Me personally if I seen a meter that said tested by Joe Smith I would buy it. well done Joe.
Hey Paul, glad you enjoyed it. I think if you stayed with meters that were certified for both the safety and EMC standards, you would be in pretty good shape from a robustness standpoint. Of course that won't help you if the meter has other problems.
Just FYI the BS1362 fuse you used in this is the standard fuse used in UK 240v appliance plugs (the huge three pronged beasts). These are sold in almost any supermarket in the UK, and come in 1A, 3A, 5A, 10A and 13A ratings. Or somewhat higher ratings after they have been wrapped in baking foil...
If you watch the series, I ended up putting in one of the larger fuses Dave provided. ruclips.net/video/fG61v8UgzA8/видео.html
0:17 - that case is amazingly transparent! Watch it with 0.25x speed! Awesome!
Amazing your work in this Multimeter! And very comprehensive testing too!
Good job, amazing! You must make sure the manufacturer gets this video.
In most of the cases it's just a lack of knowledge and insight in how to do things properly
It's a 20$ meter...what more can you expect? The manufacturer seems to have done a pretty good job at meeting decent specs at a low pricepoint. If you want superior input protection get a Fluke or Keysight.
Charge 39$ and not nearly as many people would buy it. It's about setting a pricepoint and profit margins. All things considered you can do a helluva lot worse for this money :)
The Fluke 101 is under $50 and has been a very solid runner in my tests. It doesn't cost a lot of money to make a meter more robust. The problem I see with these meters is they force the switch to handle the transients. Because I test at such low energy levels, the switch breaking down can actually save the meter. The problem with this is some people may believe, hey, that meter made it to 3KV and that's pretty good. Of course, if it did break down in real life on a high energy circuit, things may not go so well.
Came back to revisit this video as I enjoyed watching the exercise as you try to improve the meters weaknesses by improving the basic design, very interesting. I know its a lot of work and not practical but if you ever felt inclined to do this again, there are larger scale versions of these Aneng meters under various brands that would give a lot more room for you mods allowing more chances for design ideas. I know its only for educational purposes but it sure would be nice if you came up with a better version and the manufacturer would -maybe- see the improvements and at least do a little better job on the design, but I know its not likely as it would affect the price point etc. and as you said it makes more sense to just buy a better meter. Too bad they cant sell this budget version and also sell a more hardened version at a bit higher price, but again not practical from a marketing standpoint.
I doubt many people who buy these meters are concerned with their robustness. This particular meter has far too many shortcomings to make it worth investing any more time with. That is true for all of the ANENG products I have looked at. I'm sure there are people who like the meter as it is.
Agreed, the price is a big part of these meters appeal and the more ya add the more it costs.
@@yambo59Suspect the less people will buy. IMO, it's the reason why you would get one. It doesn't have much else going for it.
Fascinating Joe. Thanks for working through the process for the academics of it. BTW- one thing that other content creators do is include affiliate links in the description to items used in the video so you can get a bit of kickback without selling your soul to the advertising devil :)
I'm curious about this Corona Dope coating and the differences between it and other conformal coatings. A video explaining the pros/cons of the various coatings and demonstrating the breakdown fulcrum points of them (acrylic, silicon, this "dope", etc) would be really interesting !
Thanks again,
-=dave
Hey Dave, glad you found it of interest. I really have no desire to advertise and no plans to start taking donations. So feel free to enjoy them free of charge.
Good video Joe. Interesting mods. That was a lot of work , to bad it didn't survive because of a failed PTC.
Glad you enjoyed it. Actually, I spent less time making the mods and producing this video than most of them. I have damaged a fair number of these small PTCs.
People need to realize this is a $20 meter. It has fantastic specs for the price. I don't think you can find a better deal anywhere considering the price vs spec. If you are screwing around with high voltages using this meter, nature has her own way of getting rid of the stupid.
I wonder how much they would save by not marking the meter CE CAT III 600V. It's a whole lot better than the free HF meters.
But those are labelled CAT III 600V too. As AvE likes to call them: Harbor Fraught :-p
On a side note Joe, I'll paypal you 15 bucks for that back panel and battery holder if you sign the inside - I like the blue much better than the red on my 8008, and your range button mod is cool. I obviously won't be using it for any high voltage ;)
If you have a look at the spreadsheet, you will notice that pretty much every meter I have looked at is rated CAT III 600V and up. This is not by chance. When I first started running them, I explained this was a minimum requirement. Always good to see an unfused CAT III 600V marked meter.
Wow, I think you are the first person that has offered to buy parts from a dead one. Maybe I should auction these thing off signed and dated rather than recycle them. Someone once asked for some parts, that I ended up stripping and shipping to them free of charge to help them repair their meter. Not even so much as a thank you.
The 8002 has the switch in a different location than the 8008. I'm not sure the cover would fit now.
Nice video!!!!
green solder mask. it looks way better
What aneng model is that ? Left side
Absolutely incredible job Joe. Is there a way to test one of the Voltcrafts' meter: VC890?
Glad you enjoyed it. For some reason that meter has never been listed on Amazon.
Bravo bravo bravo
What size fuses?
hello very nice video!Can you tell what mov and ptc you have install?
i can replace EPROM 24co2a (3,3volt) for EPROM 25q64fvsig (3,3volt)
Hello, i have a UT70A where i've blown the protection on the mA range. There was a rectifier bridge with a zener across it. I have replaced the diodes in the bridge with larger ones but there was also a zener across the bridge and i can't find any info on that device code. Any hints on what kind of zener or TVS diode should I use? Thank you.
Andrei, sorry but I have never owned a UT70A. UNI-T does have some of their schematics on-line. Maybe you could find one for your meter. Another option would be to post your question under the Repair section on the EEVBLOG forum. Someone there may be able to help you. Good luck with it.
Yeah i do have the schematic, unfortunately it's low-res and a lot of the values are unreadable. I was hoping for a generic answer, like what's inside other meters you have opened up. But either way, i think i can solve this myself: I will measure the highest voltage drop that is possible on the mA range and use a zener that clamps at least 50% over that voltage, should do i guess.
I have seen one of Dave's videos on multimeter input protection where he drew another four diodes in series across the bridge, so that would be roughly 2.4 volts. But every meter is different so more investigation needed i guess.
Thank you for your answer.
Have any idea where to buy fuses for the AN 8002?
I assume you checked all the major distributors. Beyond that, I have no idea.
I believe Reachmeters sells fuses on AliExpress separately.
What about placing the two fuses in series ?
You would need to take the time to add more info to your post. Sure, we can put two fuses in series all day long. What about it?
Could it work if you place 2 small fuses in serie if there is no space for one big fuse. If number one goes open and if the voltage is that high that the current keeps flowing and number two goes open too. Will that stop the current ? Not by design but more as a "better as nothing" mod in a meter like this. Not that I will do that, it is a cute little meter I have as a toy meter and use it to check a battery or the output from a charger etc outside the lab. Handy to carry with you. Only low voltage and low current CAT1 stuff. I did a youtube review and page on my site myself a few weeks ago. ( www.pa4tim.nl/?p=5949 )
For my work and hobby I use a Fluke 77-III, Agilent U1252A and a Brymen BM869s (and some 6,5 and 7,5 digit benchmeters if I need the accuracy) I repair measurement and calibration gear.
If I need to measure current I use shunts or clamps. Except when I need to measure sub-microamps, I do that with a benchmeter or an old HP electrometer.
If we assume the meter has to meet what they marked it for, 600V CAT III, I don't think they can use a non-safety fuse and have it certified. The HRC fuses I normally see are larger like the one I show. I assume the little Asia Fuse part I installed would not be allowed and that is why UNI-T changed it out for the larger body with the GS marked version of the same meter.
That said, it sounds more like you are asking what if for example you took the two piss ant fuses that came with this meter and put them in series. Would you gain anything. I would assume the small fuse would go first. We know the fuse will arc over and once this happens, it really does not matter as there is now a low impedance path to fuse two which will then blow and of course it will arc over as well. Next I assume will come the PCB. Always good to get that copper expanding....
HRC fuses that are used in the handhelds are designed to break 10KA and up. I would say the better than nothing idea is actually worse because you have given yourself a false sense that you have improved it. There really is no substitute for buying a meter that is certified for the environment you plan to use it in.
please sir i need firmware zt102. my zt102 epprom corrupt
I doubt the firmware is stored in that EEPROM. These are fairly inexpensive. Just pick up a new one.
So most meters are not true 600 volt cat III. I see what you are testing now, Brilliant! 600 volt cat III should withstand transients to 6000 volts. I never test anything above 220 volts. I can see how this rating is misleading.
The 1000V you refer to is for continuous use, not the transient rating. The transients I apply are much lower energy that what is called out in the 61010 standards. As we have seen from my life cycle testing, the switch design is of very poor quality. Material selection for the lens is also poor. Again, all the meters are tested the same way. These meters are far down in the list.
hi, please firmware
Firmware
You should go to China and teach them how to make a safer meter.
Sorry, I really don't know much about the safety side of meter design. I suspect the mechanics have a fair amount to do with it. These tests are only about how robust the meters are, not how safe they are. There is a FAQ in the description you should take the time to read.
there's no way is safe when modify a electronic product by high voltage.
I think he said that several times in the video and he said not to do it I think it was an academic exercise maybe he is trying to shame the manufacturer into making a safer meter.
I have nothing to gain if manufactures make better products or not. It would be great if they did but really I run these tests out of my own interest. I this video, as it states, I was attempting to answer the persons question about adding a MOV and what effects it may have.