I have run the test for the dataTaker DT 600 as the thermocouple connected was showing a value of -0.6 in the Form view with the internal temperature showing a steady -1.1.
I thought this would be in degrees.

Does this mean the Datataker needs to be calibrated?
Or is it OK and I am doing something I shouldn't?

The test results are -

Hi Datamaster,

Thermocouple reading is based on voltage in milivolts.
Your TEST result showed some failure on voltage and current reference and those are the problem.

We need to check it to determine the problem, however since the unit is old it might not repairable due to some obsolete components.
Please send an email to dataTaker support email for further instruction.

Pls find the healthy DT615 status as a comparison.

Best regards,
Rudy Gunawan

OK - I will follow up with the support team.
Thanks, Stu

Result - I contacted support. Best option to trade in my DT500.
I had another look at the logger and decided to replace all the chips (IC's) in the sockets.

Ran the test and this time it was all green lights!
The cheap option worked.