Picked up a 2nd hand megger mft1721 yesterday after my tools got stolen from my van and needed one in a hurry 
Seemed ok when I picked it up, checked it and did a few basic tests all ok.
Today it’s showing err76 and shuts down after a few seconds.
I’ve tried changing the batteries and checked internal fuses, and resetting the tester but to no avail.
Anyone had this? I’ve searched online but can find very little info.
Cheers

Seemed ok when I picked it up, checked it and did a few basic tests all ok.
Today it’s showing err76 and shuts down after a few seconds.
I’ve tried changing the batteries and checked internal fuses, and resetting the tester but to no avail.
Anyone had this? I’ve searched online but can find very little info.
Cheers