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Sanwa EM7000 Analog Meter and Uni-T UT71D problem

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nukie:
Hello,
I finally got my long awaited Sanwa EM7000 FET analag meter, direct from the Japan factory. Here's a mini review I wish to contribute. I have very little experience with these meter. After testing and comparing it to a Fluke 189 with superior DC averaging function, I would say don't bother with it unless you are like me after some nostalgic memories of playing with my dad's Sanwa meter when I was a kid. The Fluke 189 totally demolish the analog meter at square wave DC 10Hz and above, advantage for it's digital readability.

The analog meter wins for anything under 10Hz but it starts to swing quite a bit when it gets down to 3Hz. The Fluke 189 produces rock stable reading that matches the analog meter, for any duty cycle percentage above 10Hz. No cheap DMM I have come close to this performance. This test puts a smile on my face, prior to this, I have no idea such performance exists in this Fluke.

I also pitted my Uni-T UT71D against the two, it does quite badly and I also found a weird flaw. Unlike the 189, it will only provide a stable reading starting from 50Hz which results matches the 189. Frequency between  1-49Hz is just some random digits jumping around. When frequency is increased to 51Hz it starts jumping around like a poker machine again, sometimes it is stable but very inaccurate. Once the frequency is raised to 100Hz everything becomes normal again. So the DC measurement is good for 50Hz, 100Hz, 150Hz, 200Hz... and so on. This goes on until 10KHz or so. Beyong 10KHz it's stable and accurate again. Hmm... if you have a Uni-T please do a test like that I did. The duty cycle of the square wave does not matter much. Sometimes the UT71D shows stable reading but the result is incorrect. When it's back to multiples of 50Hz again the result is correct.









Spare fuse, and spare fuse holders



Simple piece of device.



Toshiba N-Channel Fets

MrPlacid:
On my cheap analog meter, I found out that the red probe turns negative and the black probe turns positive when it's in resistance mode. I am curious if the Sanwa does that too.

nukie:
Yes it does, about -3.29v in the low ranges then drops to about -2.8v for x100.

MrPlacid:
Thanks, for the reply and the great review with lots of beautiful pictures.

Looking at the inside, I can tell that's no cheap multimeter. Those aren't cheap looking fuses and there is also a spare fuse inside! (I see lots of Sanwa immitations on ebay like Samwa, Sunwa, or Sanwu.) If it were chinese fake, those fuses would be cheap fuses and without a spare.

Comparing yours and my cheap "sunwa" imitation, I can tell yours is way better. Yours is a NULL meter, has power on indicator, and an on/off switch. I think mine will be sitting in a corner collecting dust, but it serve it's purpose and got the analog, nostalgic itch off of me.

I hope you find many great uses with your analog meter!

zaoka:
Is it accurate when testing DC voltage and ohms?

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