EEVblog Electronics Community Forum
Products => Test Equipment => Topic started by: blueadept on February 17, 2015, 06:24:58 pm
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Hey all,
I've not posted here, but I have watched a /lot/ of Dave's video's and done some searches, so if there is an article here with the answer I'm looking for please be gentle.
I came across this meter:-
(http://photo.tinhte.vn/store/2014/05/2494924_822892.jpg)
And it's making me sad, because this is exactly what I want... a standard meter with enough of a scope feature that I can see if there's any gross issues see a bit of clipping, tell the difference between a sine wave and a something else... and perhaps see mark/space ratio in relatively low frequency (<100khz even) signals, and power supplies.
Unfortunately, that thing is out of production for many years, and today I can only find either dedicated handheld scopes, and dedicated numerical meters... with the only exception being the Uni-T UT-81, and I already know Dave's opinion of Uni-T... plus it's the size of a brick as it's trying to be a "real" scope, rather than just an indication of the waveform.
Since I would definitely want to use the waveform feature with 240v, since I see a lot of inverters... and seeing recent reports of Uni-T being bricked with 240v on frequency range, I'm very reluctant to buy one, can anyone think of another option? Also, does anyone know any details on the Craftsman Pro meter, should I simply comb ebay for one... I bet no one would give it up if it's good!
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Try CEM DT-9989.
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Try CEM DT-9989.
From where; I’m looking a lot of time for it, but it doesn’t exist.
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It may be discontinued. Still for sale in some places:
http://www.tme.eu/en/details/dt-9989/portable-digital-multimeters/cem/ (http://www.tme.eu/en/details/dt-9989/portable-digital-multimeters/cem/)
Sorry, no stock at TME.
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That one does appear to be available to buy... has there been any teardown reviews of CEM stuff?
http://www.ebay.co.uk/itm/CEM-DT-9989-Professional-Industrial-Multimeter-Oscilloscope-color-LCD-display-/331145802493 (http://www.ebay.co.uk/itm/CEM-DT-9989-Professional-Industrial-Multimeter-Oscilloscope-color-LCD-display-/331145802493)
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Check their LCR meter:
https://www.eevblog.com/forum/testgear/cheap-lcr-meter-cem-dt-9935/ (https://www.eevblog.com/forum/testgear/cheap-lcr-meter-cem-dt-9935/)
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The TPI-440 is another such multimeter/scope combination.
I have one, and I do not recommend it. On the positive side, it does display waveforms, and can tell when clipping happens and that sort of thing. You can display waveforms of AC mains supplied by a utility company or by an inverter, and you can easily see the difference between "true sine" and "modified sine" wave inverters. It is of course isolated. You can feed a sine or triangle wave into an audio amplifier and look at the output to check if it is clipping.
On the bad side, its display is low contrast, the menu system is difficult to use and slow to respond. The scope waveform display is always AC coupled, which makes some kinds of measurements difficult. The bandwidth is narrow, basically only suitable for audio (as you'd expect from something that uses banana jacks and multimeter probes for input). The device costs more than an entry level Rigol, and offers a LOT less functionality. The only advantage the TPI-440 has over a cheaper Rigol is that the TPI is smaller, battery operated, and isolated. There are a few special use cases where that might be an advantage, but...
I don't recommend it, but you asked if there were other similar devices, and this is one.
(FYI, at the time I bought mine, probably 15 years ago, it was significantly cheaper than an entry level "real" scope. In the meantime, scopes have come down in price, but this TPI-440 seems to have kept the same price.)
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I have an Extech 5Mhz MultiScope that I bought at least 15 years ago, used. I'll echo AG6QR's sentiments about this type of instrument. When I bought it, I thought, "Hey, I need a multimeter, and having a basic scope built in would be convenient." Besides, a decent scope cost a LOT more money back then than they do now, so I thought that would hold me.
Unfortunately, what I got was much like that TPI-440. It was a terrible scope. It had a waveform update rate of less than one per second. The contrast on the dot matrix display was woefully inadequate, as was the resolution on the display. The interface was terrible because it used soft buttons for everything but the mode switch, so you had to dig through menus and scroll through time bases and volts/div. Add to that the fact that it took a second or two to respond to button presses and it was just impossible to use for pretty much anything.
But, I bought it as a multimeter... Unfortunately, it sucked for that too. Slow update speed, low contrast, fiddly menu-driven interface. It was just garbage.
I'm pretty sure every one of these hand-held scopes is a case-study in compromise. They won't be good scopes, and probably won't be great meters either.
But at least it had a built-in signal generator. :-+
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The CEM looks relatively nice, I can't find anyone who's reviewed one, or taken one apart tho, which is really a worry... I did find this, which is the 9979, but similar...
https://www.youtube.com/watch?v=zzfYm2DorWU (https://www.youtube.com/watch?v=zzfYm2DorWU)
It seems to me that all these examples sacrifice more to being a scope than the Craftsman one I linked... no wonder I can't find one on ebay.. LOL.
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Fluke had the 867B and 863B. There are always some overpriced models on Ebay.
I had one in my last company and sometimes I would like to have something like this again too. Also with my scopemeter now, I use rarely the frequencys over 1Mhz.
On the other side ... just one channel is often a pretty limitation. That's the reason why I didn't bought a Fluke 86x (and they are mostly well overpriced on Ebay).
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http://www.plccenter.com/en-US/Buy/SEARS/82289 (http://www.plccenter.com/en-US/Buy/SEARS/82289)
Still have stock apparently at $323
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I've already called PLCCenter, they do not actually have stock... notice the last update was 2004!
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I came across this thing... ripe for someone to do a teardown?
https://www.banggood.com/Upgraded-MUSTOOL-MT8206-2-in-1-Intelligent-Digital-Oscilloscope-Multimeter-with-Analog-Bar-Graph-p-1331666.html (https://www.banggood.com/Upgraded-MUSTOOL-MT8206-2-in-1-Intelligent-Digital-Oscilloscope-Multimeter-with-Analog-Bar-Graph-p-1331666.html)
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I came across this thing... ripe for someone to do a teardown?
https://www.banggood.com/Upgraded-MUSTOOL-MT8206-2-in-1-Intelligent-Digital-Oscilloscope-Multimeter-with-Analog-Bar-Graph-p-1331666.html (https://www.banggood.com/Upgraded-MUSTOOL-MT8206-2-in-1-Intelligent-Digital-Oscilloscope-Multimeter-with-Analog-Bar-Graph-p-1331666.html)
I did a review including tear down of it: https://lygte-info.dk/review/DMMMustool%20MT8206%20UK.html (https://lygte-info.dk/review/DMMMustool%20MT8206%20UK.html)
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I came across this thing... ripe for someone to do a teardown?
https://www.banggood.com/Upgraded-MUSTOOL-MT8206-2-in-1-Intelligent-Digital-Oscilloscope-Multimeter-with-Analog-Bar-Graph-p-1331666.html (https://www.banggood.com/Upgraded-MUSTOOL-MT8206-2-in-1-Intelligent-Digital-Oscilloscope-Multimeter-with-Analog-Bar-Graph-p-1331666.html)
Is it this one? https://www.youtube.com/watch?v=KujMeU4QAvY (https://www.youtube.com/watch?v=KujMeU4QAvY)