Auto null mayhem!!

[mickytuff]

Hi all using a megger multi and the auto null for the leads is playing up, you null them and then the reading goes up or even down, try again and then it mite go up even more, is it leads or meter folks, what you think all??:93:

 

[GLENNSPARK]

first thing here is are you knulling through the hinges on your crocs?.....if not and its still playing up then suspect the leads....and the plugs/sockets where the leads interface with the meter/crocs/prods.......

 

[ruston]

Make an adapter up and null one lead at a time , that will prove your lead/leads. If it is stable on one lead that is . It is unlikely that both leads will be faulty. Or if you have a spare lead vary them.

 

[tony mc]

If its one the 1500 MFT's they tend to eat batterys

Make sure the are good as when they get low it can affect the continuity readings!

 

[wildgoose]

Sorry if this sounds a little too simplistic but have you tried a new set of batteries in your tester?

The first noticeable feature on my Megger MFT to suffer with flat batteries, is the Nulling.

 

[GLENNSPARK]

agreed about batterys....and when knulling the resistance value ov leads...i always grab the crocs and hold em together firmly whilst knulling......dont forget its low ohms and if theres any resistance there....the tester will sense it....

 

[GLENNSPARK]

same when i do an r1...r2...rn.....i always grab em and hold the crocs firmly against the conductors whilst doing a continuity....