Teardown: Amprobe AM-270 Digital Multimeter

[FenderBender]

Here's another,

Bought this thing for $90. I'm quite pleased for the price. Tons of functionality and very good build quality. Pictures:

[FenderBender]

More

[FenderBender]

I though I'd do a quick review also. More like some quick notes.

Pros:

-Pretty much every function you could dream of in a DMM
-Rated accuracy is on par or better than many meters in it's price range
-Separate mA/uA jack
-High Quality Internal construction:
  +Huge HRC fuses
  +Routed isolation slots/plastic blast shields
  +Lots of input protection (vertical resistors even have their leads heatshrunk)
  +Nicel  VReference Resistor 0.1%
  +O-Rings on screwholes and in input jacks
  +Overall high quality passives and construction
  +High quality soldering. No residue or junk
  +Intriguing range selector switch...
-Appealing professional aesthetics
-Audible jack alert.  ie. Plugged in for current, but on voltage mode
-Excellent price-point


Cons:
-LCD Backlight is blotchy: no light diffuser
-"Kickstand" is a tad bit flimsy
-Range switch is a little too stubborn for my taste, not very satisfying
-No dedicated battery holder, just a compartment with a 9V battery clip on a wire.
-Scratchy continuity tester. It's quick, but irritating.

[Lightages]

I am sorry but I meant to reply earlier. This looks like a very good buy and I somehow overlooked it earlier. Thanks for the information.

[FenderBender]

I am sorry but I meant to reply earlier. This looks like a very good buy and I somehow overlooked it earlier. Thanks for the information.

I think you can hardly beat it for the price.

[amspire]

It does look a great multimeter for the price.

The one negative I could see is for current ranges of 500mA and below, it has a strangely high burden voltage.

From the Amprobe data sheet, the burden voltage is 1.65V full scale on the 500mA range and 0.75V on the 5mA range full scale.

On the 5A range however, you can resolve down to 1mA, and 500mA of current would cause a 15mV burden current and so most of the time, you could live with using the 5A range for measuring power supply current.

Richard.

[FenderBender]

Hmm...Well I don't think it was designed particularly for low voltages. More industrial wiring kind of stuff.

I don't have a scope so I don't know if would really have an effect.

Maybe I should get a uCurrent!

[IanB]

The one negative I could see is for current ranges of 500mA and below, it has a strangely high burden voltage.

From the Amprobe data sheet, the burden voltage is 1.65V full scale on the 500mA range and 0.75V on the 5mA range full scale.

It's not strangely high as in uniquely or oddly high, it is consistent with more or less every meter out there in any price bracket.

Testing a whole range of my meters gives a meter resistance of 2-3 ohms on mA ranges and 100 ohms on uA ranges. I was surprised at the consistency of these measurements. I mean every meter was about exactly 100 ohms on the 200/400/500 uA range.

[PeteH]

I'm curious, does this meter give audible warning if you switch to measure voltage and forgot to change the probe over?

[FenderBender]

I'm curious, does this meter give audible warning if you switch to measure voltage and forgot to change the probe over?

Yes it does.

[PeteH]

I could see the split input jacks, usually the usual method for detecting the probe. Looks like a good meter!

[FenderBender]

Wow you have some sharp eyes. I didn't even notice they were split jacks. Haha. Atleast there the good quality split jack type.

[sorin]

just 5000 counts

[FenderBender]

Is that bad?

[Salas]

Looks like it was designed with electricians in mind. Much input protection, hard switch for hand in industrial glove, so so tilting bail because almost always on hand or hanging off a terminal's frame, waist clip, 5000 count to have the important stuff in big size.

[Lightages]

It may have been designed for electricians, but it has all the right stuff for almost any electronics work. 5000 count? So it isn't 40000, big deal. For the price it is a bargain and safe for newcomers to the hobby/profession.

[peter.mitchell]

5000 count is amazing, 4000 count sucks big ones (not the aerosmith album either), 5000 means you can see the voltage on a lithium chemistry battery in high resolution, 4000 not so much

[multiJ]

It would have been great if AM-270 was available for sale in Europe 

[StubbornGreek]

I was considering picking up an AM-140. This little review instills some confidence...hmm

Thanks for your input.

[dr_p]

It would have been great if AM-270 was available for sale in Europe 

I live in Europe and got it for 90$+35$ shipping from Tequipement.net. It took 10 days more or less, half of that before departing the shop.

[Lightages]

I was considering picking up an AM-140. This little review instills some confidence...hmm

Thanks for your input.

Have a look at this too.
https://www.eevblog.com/forum/product-reviews-photos-and-discussion/amprobe-am-140-a/msg155623/#msg155623

[iloveelectronics]

While we are on the topic of these Amprobe meters which I believe are basically Brymen's inside a different housing and badge, I have just got myself a Brymen BM-257. I will post some pictures and perhaps a short review if anyone's interested. http://www.brymen.com.tw/product-html/cata250/Bm250s.htm

[T4P]

While we are on the topic of these Amprobe meters which I believe are basically Brymen's inside a different housing and badge, I have just got myself a Brymen BM-257. I will post some pictures and perhaps a short review if anyone's interested. http://www.brymen.com.tw/product-html/cata250/Bm250s.htm

Please do 

[retiredcaps]

I have just got myself a Brymen BM-257. I will post some pictures and perhaps a short review if anyone's interested. http://www.brymen.com.tw/product-html/cata250/Bm250s.htm

Yes, please!!!

[StubbornGreek]

I was considering picking up an AM-140. This little review instills some confidence...hmm

Thanks for your input.

Have a look at this too.
https://www.eevblog.com/forum/product-reviews-photos-and-discussion/amprobe-am-140-a/msg155623/#msg155623

Thanks. I saw those but didn't realize he was on this forum.

[multiJ]

I contacted them (tequipment) a couple of weeks ago and they said they have "a minimum $300.00 international order requirement". Go figure 

It would have been great if AM-270 was available for sale in Europe 

I live in Europe and got it for 90$+35$ shipping from Tequipement.net. It took 10 days more or less, half of that before departing the shop.

[dr_p]

I contacted them (tequipment) a couple of weeks ago and they said they have "a minimum $300.00 international order requirement".

I just went ahead and placed the order, payed by Paypal and it all went smooth. While watching the video and pictures on their site I noticed that there is also an AM-270 without bar-graph , so I confronted them and they ensured me it has the bar-graph version. It was well packed, and I'm very happy with it.

[multiJ]

Thank you very much for the heads up, I will check this out

I contacted them (tequipment) a couple of weeks ago and they said they have "a minimum $300.00 international order requirement".

I just went ahead and placed the order, payed by Paypal and it all went smooth. While watching the video and pictures on their site I noticed that there is also an AM-270 without bar-graph , so I confronted them and they ensured me it has the bar-graph version. It was well packed, and I'm very happy with it.

[FenderBender]

It's called an AM-250. All AM-270s have bargraphs.

[multiJ]

Would love some pictures and short review too, to compare this with Amprobe DMMs

I have just got myself a Brymen BM-257. I will post some pictures and perhaps a short review if anyone's interested. http://www.brymen.com.tw/product-html/cata250/Bm250s.htm

Yes, please!!!

[dr_p]

It's called an AM-250. All AM-270s have bargraphs.

This video is from tequipement's site: notice the lack of 4 buttons and bargraph And it says AM-270 TRMS on the meter!

!

[retiredcaps]

The same video is on amprobe's website

http://content.amprobe.com/video-dmm/Amprobe%20CAT%20IV%20Digital%20Multimeter.html

but the high definition pictures says "w/Bar-graph Display"

http://content.amprobe.com/HighResImages/am-270.jpg

[iloveelectronics]

The same video is on amprobe's website

http://content.amprobe.com/video-dmm/Amprobe%20CAT%20IV%20Digital%20Multimeter.html

but the high definition pictures says "w/Bar-graph Display"

http://content.amprobe.com/HighResImages/am-270.jpg

They don't even look like the same meter. One has 8 soft buttons while the other only has 4! Confusing...

[cybergibbons]

It would have been great if AM-270 was available for sale in Europe 

I live in Europe and got it for 90$+35$ shipping from Tequipement.net. It took 10 days more or less, half of that before departing the shop.

Pretty much my experience as well, though I got raped on customs charges.

[dr_p]

Ok, been using this for some time and I've got things to tell you:


To silence the beeps when pushing buttons, one can hold Hz button while powering on via rotary selector. When the meter enters auto power off, one can wake it up by pressing any button, not just the select button like the manual says. But surprise-surprise, the beep is now ON, so I'm forced to rotate the selector to OFF, then desired range again while holding Hz (the usual way).

Now I accidentally found that if you wake it up from auto power off by HOLDING the Hz button, meter says "dsbld" or whatever it usually says (e.g. disabled beep) and beep is still OFF. 

Hope it helps some people. Funny fact: I was so happy I found this out and my sleeping GF won't be bothered by the beeps that I reverse mounted an electrolytic cap (100uF, 50V connected to 27V). It was like 1:00 AM and I was troubleshooting some analog stuff  . 40 seconds later I smelled something heating up and glanced at my MAVO35 just to see it at 10mA and then violently shoot to full scale(100mA) . I touched my 2 ICs but thy were ok, then I spotted the cap bulging in my face. I mean like 20cm away. First thing that went through my head was UNPLUG THE SCOPE, I JUST BOUGHT IT!!!  Don't look for any logic in that, it's not like it will ever get electrically damaged by a bursting cap . I managed to unplug it and just started turning my head away when it exploded in (almost) my face. I'm totally fine, thank you. %-B

The moral is: leave the beep on, it saves you from caps exploding in your face. 

[jhufford]

So after a few years of using this meter, any final verdict? Is it suitable for general electronics work or only for electricians? From the specs it looks pretty good for electronics work. It has a 50mV and 50 Ohm and 500uA range and quick continuity tester...

I'm comparing it to the BK2970B or 2712 . But the BK doesn't have temperature and its beeping when turning the switch is darn near a deal breaker. Duty cycle is about the only thing missing from the 270 and it's frequency bw is only 125k but good enough for quite a few of the switching circuits I do, I can use the scope for anything higher than that.

I tend to do an odd smattering of projects, from battery power microcontrollers to high-voltage with flyback transformers. I thought the the am-270 might suit nicely and be a nice replacement for my <$50 ideal meter.  (or might the BK and a separate temperature meter be best?)

Thoughts anyone?

[Lightages]

It was a great buy when it was only $90. Now it is $105 so not quite as nice a deal but still good. I would still recommend it for anyone who needs a well built, safe, and accurate meter for around $100. I don't have one but it is the same as a Brymen BM815. I haven't heard anyone complain about the 270 except for the bad back light.

[dr_p]

I did a backlight mod today - replaced all 4 LEDs with high efficiency red ones. Whites would not even light up, as voltage before the resistors seems to be 2.4V. I couldn't be bothered to research more, so I just put the red ones in and they are clearly more bright than the stock green. Also added 3 layers of matte film from a broken LCD screen. The one that looks like sandblasted glass. I tried to space them referenced to each other, as to maximize the light dissipation.
For reference, stock backlight is very bad, similar if not identical to this Brymen: https://pbs.twimg.com/media/BCiSbY8CMAAGMDZ.jpg
I also added some pictures with the areas that the OP missed - main chipset and the back side of the PCB.

[Johnny Electron]

Just to add info for new buyers which may be searching these old threads, the backlight is now fixed!  It is now a nice orange like the brymen meters when the 's' was added to their model numbers.

[AndyBollo]

Hello!

I bought the AM-270 on Dec'2013 and it already came with the nice orange backlight.  Almost 4 year now and I still very happy with the purchase, is a very useful and good equipment. Perfect for electronics repair.  DIYers should no look further.

[osteichthyes]

I don't mean to resurrect an old thread, but I've been using one of these for about a year and I absolutely love it. I was recently offered a sweet deal on a Fluke 87 and realized that aside from its great form factor and nice feeling in the hand, it really didn't do much my 270 doesn't. And the Amprobe does a lot the (original) 87 doesn't. All that is to say, it's a heck of a meter! (I don't mean to suggest that a comparison of products made 20+ years apart is reasonable, but rather that it does a lot of things really well).

I did notice one oddity when I took it apart recently. Around the input jacks, there's a piece of plastic that runs in the slit in the board. On my AM270, the battery wire ran underneath this plastic and actually got pinched a bit. So, I took the board out and ran the wire around it. This meant the battery wires run directly on top of the 10A input jack. Which, I'm sure is fine, but it seems like a surprising design oversight. Anyone else have any thoughts about this?