fluctuating resistants reading megger met 1710

[billy]

Hello I'm getting fluctuating resistants readings when using a megger mft 1710 meter, Does anyone know whats causing this / how to mend it. Ive tried taking it apart to have a look inside but can't even take it apart does anyone know how too (ps its not the same as the older testers)

 

[ChipFanDave]

Well it depend on what you are testing or it may be the leads but I wouldn't think It would be something you can fix easily by having a look inside. There are screws under the batteries and I think under the label as well. I use Universal Instruments in Leicester for calibrating they are a good company for repairing test kit as well. Not sure were you are but I'm sure you can find some one local with experience in fixing your Megger. If not bin it and get a new one delivered next day, we are all on thousands of pounds don't you know and time is money!!

 

[telectrix]

first try your leads in a mate's tester, if OK, then clean your 4mm ports in your megger. failing that, it could be a dry joint inside the megger, on the ports, or on the connections into the pcb.

 

[Octopus]

Try it on a reel of new cable .....

 

[westward10]

Chuck it in a skip and buy a non mft tester.

 

[billy]

I've tried different leads, also cleaned the ports, would check the pcb / joints but can't even get inside. its not like my old mft 1553 where you take the sicker off and undo the screws. I've never seen a case like it on anything

 

[billy]

westward 10 im seriously considering that lol. do you use separates? if so which ones, how do you find them vs a mft

Chuck it in a skip and buy a non mft tester.

 

[Gavin John Hyde]

most things with a mft giving iffy readings can be down to one of 3 things, batteries, the leads/contacts or the fuse inside.
Not sure about meggers and whether you can access the fuse to check it is seated tightly. but with others that can help.
change your batteries, clean the leads and test against known values.
Also check how you null your leads out.

 

[MDJ]

Try Zeroing the leads first, unless you do that the readings will not stabilise.

 

[billy]

most things with a mft giving iffy readings can be down to one of 3 things, batteries, the leads/contacts or the fuse inside.
Not sure about meggers and whether you can access the fuse to check it is seated tightly. but with others that can help.
change your batteries, clean the leads and test against known values.
Also check how you null your leads out.

Done all of that, no point testing against known values because its not consistent. If I move the connectors it changes

 

[buzzlightyear]

Try Zeroing the leads first, unless you do that the readings will not stabilise

a hammer will do nicely .

 

[westward10]

westward 10 im seriously considering that lol. do you use separates? if so which ones, how do you find them vs a mft

My separates are a Robin loop tester and insulation tester and a Megger rcd tester, no problems whatsoever. Colleagues use mfts and they seem to spend all day faffing with them.

 

[The Ghost]

I had an amprobe mft and if I left it in the vehicle overnight the low ohms resistance readings went crazy. I assume it was condensation in the MFT. What degree of fluctuation is there 1 ohm to 200 ohm or 1 ohm to 20 ohm? You have no doubt ruled out the circuit you are testing and presumable get this on any circuit?

 

[Wilko]

Done all of that, no point testing against known values because its not consistent. If I move the connectors it changes

Can you null it as per @MDJ?
Moving the leads changing the reading tells us it might be ... .....

 

[Midwest]

I had a similar issue with my 1730, turns out it was a cracked terminal. How old is it?

 

[Octopus]

Done all of that, no point testing against known values because its not consistent. If I move the connectors it changes

If it’s not reading a known value consistently and you have replaced the leads them it needs to go for repair ...

So it’s the manufacturer or an independent repair shop

Where are you based as Englan is a bit vague

 

[Octopus]

Done all of that, no point testing against known values because its not consistent. If I move the connectors it changes

If it’s not reading a known value consistently and you have replaced the leads them it needs to go for repair ...

So it’s the manufacturer or an independent repair shop

Where are you based as Englan is a bit vague

 

[JOURNEYMAN]

Zero leads, replace batteries, check leads, check battery connections. Don't leave meter in van overnight ( prevents damp getting into the meter). Other causes of fluctuating readings is usually attributed to either damp in the cables or newly plastered walls. I keep my old mft calibrated as a spare 'go to' if I have suspect readings and for use while my main meter is being calibrated. Mft's can be temperamental bit like the missus!