Multimeter Review / buyers guide: Part 3 - UNI-T UT61E - Look inside

[MJLorton]

Here is a link to the video review: (To be posted once upload complete)

Pictures taken of the PCB of the UT61E and some captured of the Agilent U1272A during the review (comparing input protection).

[DaveXRQ]

I shall copypasta what i wrote before

So i got down to do some tests on power consumption (naturally with a almost identical twin)
9V (Batteries start fresh at 10V but that's unloaded)
1.5mA on capacitance even while measuring a 10mF cap... Big i know
1-2mA on voltage Actually i was pretty shocked it only draws that much at this price point and best part is that the screen is actually more viewable than the 87v As in better contrast and brightness(This is a true reply, my friend uses the 87V at his college, well i mean everyone there uses it)
Didn't really test the rest but when it's in continuity mode with beeper sounding it's about 4-5mA

Okay, here's the most important part some might want to know.
Low voltage performance? Measured at PSU but it doesn't matter, my psu is pretty accurate but i still used it's twin i got from DD to measure the PSU voltage
Battery LV warning? Starts at 5.35V and stops at 5.45V
Voltage where the measurement starts to drift? Doesn't seem to drift above 3.5V but i can't really tell. Even my ET-845 seems to drift way more with fresh batteries, the UT61E doesn't seem to drift before it turns off! I was a little worried when i saw it happening yesterday then i forgot i wasn't using banana plugs
Voltage where it turns on? 2.1 Seems to be right, the datasheet says -2.5 to -3.5 so i'm seeing witchcraft here or is it a buck-boost converter?
I'm seeing ±5V on the AD737J so i'm pretty sure the UT-61E has a buck-boost converter

So my testing is complete, if you do need anymore measurements i'm glad to provide
(This lodestar 8202/8203 psu is freaking impressive, 33 year old caps and they hardly drift or have hardly any noise at all!)
Oh yes i forgot, i intentionally added a 330ohm resistor for the supply

About the fuse, you can install HRC fuse sockets because the footprints are there
The fuse is indeed HRC at 6kA being a mains fuse! But it's only rated to 250VAC AND NOT DC! -Sorry about that monkeh
My recommendation is to try out the same 10A 30kA 10x38 siba fuses agilent uses, 10x38 will fit in the 1A fuse socket with a bit of fuse holder bending or you can use a 500mA 1000V 6.3x32mm 30kA-50kA fuse, just remember to silicone the exposed holes, might lead to arc overs
"Sparkgaps" Go ahead and install a MOV there of some reasonable rating

[retiredcaps]

Well I was going to sleep, but then saw part 3 posted.  Some observations/comments that you asked for in the video (will add as I watch and review again in the next couple of days).

1) The fuses are

http://www.betterfuse.com/news/html/detail-38.html

Dongguan Better Electronics Technology Co.,ltd. announces the introduction of the AF63 Series today, BS1362 standard fuse with rated current from 1A to 13A.
AF63 series presents a big breaking capacity with 6000A at voltage 264V, the electrical characteristic is fast/medium action.

2) The fuse (namely the 10A) in your UT61E looks different from the GS approval one posted at Torrentula

http://mjlorton.com/forum/index.php?topic=140.15

3) The GS approval model also has different PTCs and a SG added.

4) Just curious, for the low battery test, do you actually have a <3V (aka dead) 9V battery to test instead of a DC power supply?  (In Dave Jones' $99 shootout, the UEI DM391 worked down to 3V on a 9V battery DC power supply).

[ModemHead]

I repeated Martin's low-voltage experiment and this one seems to work pretty well at 2.00V. It will even still measure resistance, giving essentially the same readings as it does at 9.00V. The beeper gets pretty faint, as one would expect.

If you're going to go down the route of upgrading the meter, I might suggest adding a high-quality 10-turn trim potentiometer to replace VR1. The UT61E I have here drifted horribly when I first got it. Never the same reading twice. It improved considerably after I exercised (ran back and forth a couple times) VR1 and then re-calibrated it. I noticed during the calibration exercise that VR1 was very touchy and did not inspire confidence.

But don't replace VR1 unless you have the means to re-calibrate!

[Monkeh]

But it's only rated to 250VAC and 32VDC.

They are not DC rated at all. How many times...

[SeanB]

A 9V battery that is at 3V will have a pretty high internal resistance. 5V will drop to 3 when you draw 2ma or so.

[Kiriakos GR]

They are not DC rated at all. How many times...

Yes this is true, I did read also the spesifications, it is sad the fact that UNI-T has use one oversized 220V fast fuse, instead of a true high voltage HRC.
Due all the inregularities which are found on this model, my decision is to stop following any conversations about it.
But what I am still wonder is if all the 61 series is all alike with this death trap. ?   

[Monkeh]

They are not DC rated at all. How many times...

Yes this is true, I did read also the spesifications, it is sad the fact that UNI-T has use one oversized 220V fast fuse, instead of a true high voltage HRC.

Please explain how it's oversized or 220V. Facts, get them straight.

And it's quite adequate for what the majority of people will use this sort of meter for.

Due all the inregularities which are found on this model, my decision is to stop following any conversations about it.
But what I am still wonder is if all the 61 series is all alike with this death trap. ?

Yes, they are all the same as this 'death trap' (reality, try it some time).

[Kiriakos GR]

They are not DC rated at all. How many times...

Yes this is true, I did read also the spesifications, it is sad the fact that UNI-T has use one oversized 220V fast fuse, instead of a true high voltage HRC.

Please explain how it's oversized or 220V. Facts, get them straight.

And it's quite adequate for what the majority of people will use this sort of meter for.

Due all the inregularities which are found on this model, my decision is to stop following any conversations about it.
But what I am still wonder is if all the 61 series is all alike with this death trap. ?

Yes, they are all the same as this 'death trap' (reality, try it some time).

Should I take you from your hand to visit together the betterfuse link, and to hold your hand when you will read the PDF with the specifications ?
Honestly all this attitude about  this damn multimeter about honoring something technically FAIL it is WRONG.
If there is out there people ready to swallow all the drawbacks due the low price, I am not one of them.   

[Monkeh]

Should I take you from your hand to visit together the betterfuse link, and to hold your hand when you will read the PDF with the specifications ?

Should I give you a copy of BS1362, which I have read cover to cover? The fuses are not 220V, and nowhere is that value mentioned on the Betterfuse site, either. And I still want you to explain what 'oversized' means.

Honestly all this attitude about  this damn multimeter about honoring something technically FAIL it is WRONG.

And your attitude is wrong, too. But you'll never see it.

If there is out there people ready to swallow all the drawbacks due the low price, I am not one of them.

You are, however, one of the people able to spend an order of magnitude more on a meter. Good for you. You also have very, very high expectations for meters which we're discussing for use on electronics, not industrial electrics.

[Kiriakos GR]

Well here is your chance to prove me wrong, post the magic PDF with the 1000 pages. 

[Monkeh]

Well here is your chance to prove me wrong, post the magic PDF with the 1000 pages. 

How about you just read the voltage rating on the Betterfuse site, which lines up perfectly with BS1362: IE. it's not 220V.

[Kiriakos GR]

Take a snap shot and post it.

[Monkeh]

Take a snap shot and post it.

http://www.betterfuse.com/MyUploadFiles/InfoPath/201204/20120409133652507.pdf

Read it for yourself. It quite clearly says 240VAC.

[iloveelectronics]

OK, I don't understand the big fuss about the voltage rating on the fuses. They are for the A and mA ranges, right? And it's marked clearly on the meter that both ranges are fused at 250V max, i.e. nothing more than the mains power. And those fuses are rated correctly, aren't they? Or am I missing something?