Mestek DM90, 6000 Count TRMS, uA Range, NCV, VFC

[sleemanj]

Another cheap (sub $20) Chinese meter arrived in the post today. 

Mestek DM90, lSNAKOL SY76 looks like another branding, maybe more.

Positive: cheap ($15-20 Aliexpress) 6000 count hand-sized meter.  Sturdy construction.  3xAAA cell.  Has a 600uA range (and 60mV range).  Ceramic fuses (5x20mm - 250v).  NCV, led torch light (flashlight), and "V.F.C" mode (AIUI adds a low-pass filter to the AC voltage mode for measuring variable frequency drive voltages?).  Flashlight has a dedicated button, seaprate to the backlight (many meters share the function which is annoying).   Marked as 600v Cat II which I rate as a positive because at least they are not being blatantly outlandish.

Negative: flashlight not very bright.  The rubber boot has cut outs around a "grip" moulding in the plastic case, that's just silly it means the plastic seam of the case is exposed.  Does not have temperature mode.  Manual indicates fuses are 700v, they are not, and no marking on case to indicate 250v on current ranges either.  Dial markings are maybe a little on the small side.  Fair amount of chinglish in manual. And the big one... the banana sockets are a fraction too small for some plugs! 

Seriously, the banana sockets are like 0.2 maybe 0.3mm too small (diameter) to comfortably fit my preferred banana plugs, which fit in every single other meter I have, they will go in partly, but it's waaay too tight.  The probes fit in fine, as do cheap "leaf spring" type banana plugs, but the good high current ones, nope. I've never encountered a banana socket they don't fit in until now.  Some other multimeter probes also have trouble seating in there all the way.

Even before I plugged in a, err, plug, I looked at the sockets and something just looked "small" about them, which caused me to grab a banana plug to try.

So in short, good set of features, great price, well constructed, let down at least for me mainly by fractionally too-small sockets.



High current banana, about as far as I can force it in (and I do mean force), normal "leaf spring" type bananas are ok


You can see it just doesn't go all the way in, the socket is too tight


Rubber boot has these cutouts where the plastic case has a moulded "grip" section.


Otherwise it's a tidy meter assembly, not bad, just those damn sockets a real shame!



The high current banana on the left, and the leaf-spring style on the right...