Martindale et4000 high readings, calibration?

Craighrvy · Oct 2, 2020

Hi all

I've just purchased the martindale tester second hand from ebay.
In comparison with my metrel mi3002 and ht macrotouch, it is giving almost twice the readings.
In my mind, this is a faulty unit, as calibrating will only check the tolerance, and if the readings are this far out, it will need some form of adjustment, at some astronomical cost I imagine.
Has anyone else experienced this with a tester before, and how much did it cost to put right.
I need to confirm if I need to send this back or at least a cost I can negotiate with the seller as its in really good shape
All tests in the pictures performed at the same socket, in both sides of the socket

Cheers

James · Oct 2, 2020

Beware, testing a socket with another tester plugged in can cause errors in the results.
Make sure there is only one plugged in at a time.

Julie. · Oct 2, 2020

Check the settings as some require switching of leads others just use software/setting selection.

But you need to make sure the physical lead connection and settings match.

Also that you use the same type of test, 2 wire, 3 wire, and high/low current

Craighrvy · Oct 2, 2020

James said:
Beware, testing a socket with another tester plugged in can cause errors in the results.
Make sure there is only one plugged in at a time.

Unplugged each time and only testing one at a time

telectrix · Oct 3, 2020

maybe the martindale need the leads nulling for ZS. what's it like on other ranges.

pc1966 · Oct 3, 2020

Measuring Zs/PFC is very dependent on the connection/lead resistance. Some might allow you to null that out (maybe as part of normal low-ohm procedure?) but others (like my DiLOG) have it as a factory cal setting.

Which is stupid as it is not mentioned in the handbook (I had to ask their technical support) and it means you can use non-standard cables and expect accurate results as you would id lead nulling was possible.

Ideally they would be using Kelvin style leads (separate current-force & voltage-sense) but only the big and expensive loop impedance meters seem to offer that option.