MEGGER MIT515 WITH VOLTAGE FAULT

[HUGOMAN]

Hello

i have Megger meghometer mit515, when i apply a test in range 250V it displays only 7 to 10V! please advice about this issue, and it occur the same thing with all voltage ranges.

Thanks in advance

Regards

[shakalnokturn]

This could come from various to things: Measurement section, HV generation, input/output protection.

Have you checked the fuse? Has there been battery leakage?

Other than displaying a low voltage during isolation tests what resistance does it display on same tests when open and measuring a known resistance such as 100k Ohm?

What display do you get when measuring a known voltage?

I don't think schematics are available so you may get more help by uploading a few detailed internal photos.

[HUGOMAN]

Yes shakalnokturn

i want to know where the fault comes!

1/ i've checked the 2 fuses are ok. plus the smps 220V to 24V ok
2/ battery leak---> i measured 12,2V but the connector pins has only 2,2v in each side. i guess the level of battery voltage is up that's why.
3/ i put 7W resistor of 100ohms ----> it reads 10,00Kohms with 1volt (very strange)
4/ yes sure the known voltage 250V with the load of 100ohm gives 0 to 1volt then without load gives 11 volts in every known voltage range switch.

thanks

[taydin]

Before anything else, check to make sure that when you configure an IR test with 250V, with nothing connected to the terminals, that it really does output 250V. If it doesn't then the problem must be in the step up converter.

[HUGOMAN]

 Thank you Taydin for your response.

You have right because there is no voltage at the output olny 11V means that there is a short circuit or what in this stage of step up converter.
the problem that i couldn't find in the internet 2days ago any service manual or technical documentation for this mit515 Megger model.
 

[shakalnokturn]

[autoquote]

I don't think schematics are available so you may get more help by uploading a few detailed internal photos.

[/autoquote]

Shakalnokturn enjoys the autoquote function...

I got to see the photos on the other topic, keeping things in one place will get you higher chances of actually finding help.

So as said taydin: You could check on one of the lower test voltage ranges and using a dmm what voltage your MIT515 actually generates.
One of my previous suggestions was to check the measurement section of your MIT515 using it as a voltmeter to measure an external voltage source.

[HUGOMAN]

Thanks to you shakalnokturn and taydin for your help.
i have performed today these 2 methodes.

1/ the megger mit515 generates only 0,2volts dc; this measured by fluke dmm.
2/ the external voltages measurement, it measures up to 1999VAC and VDC too when it exceeds this value no displaying. but the values are incorrect the 100Vof externel source  it reads 1500V. so it means that the true 200Vac or DC can not read it.

I hope you clarify to me the faulty stage.

Regards

[HUGOMAN]

Can someone help with thi problem; who is no voltage at the output of megger meghometer ?

[HUGOMAN]

Unfortenately, i see no contribution for this issue!

As you know there no technical data for this instrument available on the internet; by this opprtunity i ask kindly all Eevblog community to share with me how to solve this fault on MIT 515 MEGER.

Specially the fault in the output voltage, it is measured is given 0V, and it displays 17V instead of voltage positions switch from 250 to 5KV.

Also i noticed that the white connector it is always on 0V the one that supplies the second part even the red led power is going on.

To read

[JKKDev]

The community is more than willing to help you but you have to actually respond to their requests.

As people above have mentioned please open the device and take a few pictures of the internals. This will help with diagnosing the issue.

Your request for information based on nothing but a few measurements is an impossible task except for maybe the small group of people that might have owned/repaired this exact unit before.

Based on this I'd suggest you answer ALL of this questions:
- Are you willing to open the unit up? If so take pictures of the insides.
- What kind of test equipment do you own / you can use to diagnose the fault?
- Do you have any prior experience with working on this type of equipment? (I'll be honest, I've got no idea if this is battery or mains powered)

And finally a line of thinking that so many people seem to miss these days: It's already broken Bob, it's of no use to you so why don't you at least try to fix it. You can always throw it in the bin later.

[Neilm]

2/ the external voltages measurement, it measures up to 1999VAC and VDC too when it exceeds this value no displaying. but the values are incorrect the 100Vof externel source  it reads 1500V. so it means that the true 200Vac or DC can not read it.

The MIT515 is only rated for 600 Vac. If you have been able to apply 1999 Vac to it I am very surprised. Did you measure how much current was passed from the supply when you did this? Like most insualtion testers, the MIT515 will discharge a load at the end of the test. In this case by the expedient of putting a reasonably low value resistor accross the terminals. Putting 2 kVac into is sounds like the resistors are damaged which may mean the output filter stage is damaged.

As you can chage the battery in it, just opening the case by undoing the 4 screws on the bottom should not invalidate any warrenty on it, just don't open the HV enclousure.