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Taligent 15th June 2005 06:28 PM

MCM sale: Tenma autoranging RS-232 DMM, $25
Hi folks,

Just got a notice from MCM - the Tenma 72-6870 DMM is on sale for $25 (usually $50). Autoranging, RS-232 interface, temp, capacitance.

Use code EM440 at checkout.

- Nikhil Choudhary

fcel 15th June 2005 06:58 PM

So, it is a good & convenient meter for general use? Other than price, what is particularly "good" about this meter? Just curious.

Where can I order one? Web link?

Variac 15th June 2005 08:05 PM

Hi Taligent,

Great info!!! I ordered one with your special code, and sure enough:
$24.99 The ONLY feature I would have liked would have been inductance, but it otherwise has LOTS more stuff then you would expect- even at $50. What a deal!!!!!!

There is a link in the text of his post. I then had to go to other parts of MCM to register, etc. This meter has TONS of features, and the brand is a cheaper but I believe, well known brand. Common wisdom seems to be that these cheaper meters are just fine.

This one has extras some don't: capacitance, temp, compiuter link, some sort of frequency meter, etc. I'm no expert but this seems to be a greart deal.

mlloyd1 15th June 2005 08:25 PM


Nice catch! Thanks for pointing it out.

For skeptics, see more at Tenma's web site:


fcel 16th June 2005 12:12 AM

What the hell, I bought one too. Thanks Nikhil.

Schaef 27th June 2005 03:21 PM

Okay, I ordered one of these, got it in the mail the other day. Looks nice and everything, but I'm running into a problem. It doesn't seem to read voltages correctly. So, now I'm wondering what I'm doing wrong, or what.

I have a second cheapie DMM that I'm comparing with, and it seems to work flawlessy, versus the readings I'm getting with this thing. Here's what I've tried, I stuck the probes into the wall socket, cheapie set at 400Vac, reads approximately 110V, the Tenma unit, 300mV! Turned off the auto features and set to AC, and no real change. What gives? What am I doing wrong?

I also tried reading off a PS that I have, again, cheapie reads perfectly fine, the Tenma unit, crap readings.

I tried the temperature sensor probe, and it seems to give valid readings, so unless there's two different routes inside the unit, it looks like a fuse isn't blown, I'm just having issues reading or setting things.

Any help would be appreciated!

P.S. - As a slight addendum, I'm plugging the two leads into the right two connections on the unit, in case I'm doing that wrong.

fcel 27th June 2005 03:47 PM

So far, I have only measured DC and it works fine. It beeps on the continuity test. So into the tool box.

I'll do some AC measurement when I got home tonight and I'll report back.

Variac 27th June 2005 03:56 PM

Of course first set the rotary knob to "V" .
There is a button right under the display: "SEL" that you have to push to tell it what you want to measure. Push it until you get to "AC" on the left side of the display.

I measured my outlets. 121.7V . That's in the morning before everyone is at work. Seems like an forbidden pleasure to stick things into a wall socket!

fcel 28th June 2005 12:49 AM

It reads 121.5VAC at 5:45pm. Meters works as advertized.

Schaef 28th June 2005 01:25 PM

Problem resolved...
Well, I took another look at my meter last night, and found the problem! It turns out, I made a mistake when I ordered. I apparently should have specified that I wanted a meter without the pre-blown fuses! I got a clue when I set the unit to continuity testing and it just started beeping randomly. Popped open the case, and sure enough, the low-power fuse is blown! Go get a new fuse, and, amazing, it reads everything correctly!! Thanks for the help guys, and apologies for not first double-checking the fuses!

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