Brymen BM257s low diode voltage drop readings.

[belzrebuth]

I noticed today that my 257s is reading lower voltage drop values compared to my UNI-T UT61E and a cheap transistor tester.
For example for the same diode the brymen reads 0.459v while the uni-t reads 0.517v and the tester 0.592v
I measured the test voltage of the Brymen and it is about 1.57V while on the manual it states that it should be about 1.8V.
The UT61E's diode test voltage is about 2.84V.
I replaced the batteries on the Brymen just in case but no change..
Is there something wrong with my unit or that's normal?!
I'm mostly worried about the lower than stated diode test voltage not the readings per se because if I connect the two meters in parallel to the diode I get almost the same reading.

[Kleinstein]

In diode test there is usually a predefined current to test the diode. That current can be different between meters. Having something like 58 mV lower voltage reading suggests the current is lower by a factor of about 10. This is easy to measure with an other meter. The open circuit voltage is not that important - it only give a maximum value and might be interesting if you want to test LEDs. With only 1.6 V, yellow LEDs might not conduct very much.

[belzrebuth]

It's not important that Brymen states as open circuit voltage about 1.8vdc typically and I get 1.57v ?
Test current for the brymen is stated at 0.56mA but I can't find any info about this on the UT61E manual.


EDIT:
I tested one meter at a time in diode mode and the other in current mode with the black lead attached to the cathode of the diode and the red via the other meters' mA jacks and I got the following.
(I used identical pairs of bananas to mini-grabbers as test leads.)

BRYMEN 0.345mA 0.460v
UNI-T     1.42mA   0.517v

[Kleinstein]

The difference in current is smaller than I expected. The more usual value is 1 mA . So the Brymen is one the low side, and the UNI-T on the high side.

The rather low voltage, when open circuit could be a sign that the batteries are not that good any more.

[belzrebuth]

Batteries were my first thought too so I replaced them with new anyways.
Maybe I could try different batteries.
I used Energizer, I could try Duracell but I think that with new batteries initial voltage differences are very subtle.