Possibly a bad Brymen 869 ?

[z4567]

Hi,

I know this is among Kiriakos' favorite multimeters from what I read on internet, but I have had bad luck with one I purchased on the local market from a reputable company.
The device was at the limit of or beyond its tolerance interval and did not exhibit the same accuracy as on Martin Lorton's videos for example, where it would agree with a Fluke 289 up to the mV level.
Also I have found that a single short push on the 500000 button would not let me switch to the 500000 count mode, I had to keep it pressed 1-2 seconds to get this achieved.
What is your experience with that device? Do you just think I had a bad one? A substandard device, bad luck? The seller refused to replace it, saying another one will behave the same way and accepted to give refund after the return of the product.

[Kiriakos GR]

Any properly written problem report note, it should include the DMM firmware version.

[z4567]

Any properly written problem report note, it should include the DMM firmware version.

Kiriakos it is already gone back to the seller, for a refund:)
Gosh I should have written down... I shall remember in the future (hope that does not happen again).
The device was sent back to the sellers' cal lab and they answered it is ok
But they did the measurements in 50000 count mode, of course the last digit which would show the problem was missing... I rejected these measurements and asked them to redo these measurements in 500000 count mode. They just did one measurement: 10mV measured as 10.007 mV. Now we are at the microVolt level here but it means a 0.07% deviation which does not meet the spec of 0.02%+2digit does it?

[Kiriakos GR]

Regarding the single button pressing at 500000 button, this belongs to Relative function, the two seconds pressing is the high resolution mode.

This is significant lack of responsibility of you, about reading the manual dear friend.

In 500.000 counts mode, the accuracy should not be calculated by the displayed value on the screen, but  manually by taking in consideration the specification in 500.000 counts mode.

Accuracy is +-(% reading digits + number of digits) or otherwise specified, at 23C &
less than 75% relative humidity.

The specification of 0.02% + 2d at 500.000 counts it is rather relaxed one for ultimate accuracy.
But you may always spend 1000EUR or more, so to get a bench top meter which would do a better job.

[z4567]

Regarding the single button pressing at 500000 button, this belongs to Relative function, the two seconds pressing is the high resolution mode.

This is significant lack of responsibility of you, about reading the manual dear friend.

In 500.000 counts mode, the accuracy should not be calculated by the displayed value on the screen, but  manually by taking in consideration the specification in 500.000 counts mode.

Accuracy is +-(% reading digits + number of digits) or otherwise specified, at 23C &
less than 75% relative humidity.

The specification of 0.02% + 2d at 500.000 counts it is rather relaxed one for ultimate accuracy.
But you may always spend 1000EUR or more, so to get a bench top meter which would do a better job.

I have just purchased an HP 3478A for $93 + shipping which is much more accurate after 14 years without calibration in fact. May be I was expecting too much of that device.

Regarding the 500000 count button, ok I did not read yet as I have sent it back straightaway, I was so upset, but watch Martin's video; a single short press gets him in the 500.000 mode. How come?

[Kiriakos GR]

He does not have a BM869.

[z4567]

He does not have a BM869.

Do you have a BM867?

[Kiriakos GR]

Personally I do not use average measuring meters, only True-RMS.

[z4567]

In 500.000 counts mode, the accuracy should not be calculated by the displayed value on the screen, but  manually by taking in consideration the specification in 500.000 counts mode.

Accuracy is +-(% reading digits + number of digits) or otherwise specified, at 23C &
less than 75% relative humidity.

The specification of 0.02% + 2d at 500.000 counts it is rather relaxed one for ultimate accuracy.
But you may always spend 1000EUR or more, so to get a bench top meter which would do a better job.

I am looking at the specs of that dmm but I do not see a different specification for the 500.000 counts mode. For example for the 500 mV range it seems to be 0.02%+ 2d.
A reading of 10.007mV instead of 10 mV does not fit in that range even by manually adding the 2 digits. Am I missing something?

[Kiriakos GR]

Regarding accuracy specifications there is no chance to be different when the range switch is in the same position.
From the other hand every comparison it is valid only when you have a voltage source that is designed for this purpose.

Impedance of a circuit and bourbon voltage of the DMM they do influence the measurement.
In general all end users testing their meters in any application that they work with, but in sensitive measurements in the range of few mV such measurements should and must be conducted only by an Oscilloscope.

Or by a multimeter that comes with very low mV range, such meters are the Agilent U1272A with 30mV range and also the DE208A which has 60mV range.

In conclusion it is in your best interest to stick to ITTSB as source of information, because the owner of it, other than be experienced in the field he has watch many seminars regarding quality of measurements too. 

[z4567]

The pics of the calibrator is attached. A 5500A...
But they did the measurement in the 50.000 count mode, so I asked them to repeat in the 500.000 mode.
Thank you for the advice regarding the Agilent. I tried to purchase a used 1252B on ebay but there too I had no luck. The device had an offset of -3.6V with the inputs shorted and the square wave output was dead. I sent it back. A lot of misfortunes these days... I have better luck with the bench dmms
I purchased my various new and (mostly) old handheld Flukes on ebay too but there was no pb.

Anyway thank you for discussing. This is a useful forum for sharing and learning from your experience of using those test gear.

P.S. I removed the pic of the calibrator because it shows the name of the cal. lab.