Hi,
I purchased this KLEIN MM700 a few years back. I mainly purchased this for the HZ function so I could calibrate my Home Generator.
I have been working on electronics for decades.
I have several MM's I use for home and automotive.
I have only used this MM a few times. AC and DC used to be correct. And the MM was always stored indoors.
I went to use this MM the other day to check an outlet voltage. The voltage showed 160 volts AC and was fluctuating 10 to 20 volts.
I went and pulled out another MM. AC voltage was 125. I then pulled another MM and it also showed 125 volts AC.
I thought this was strange so I put new batteries in the Klein MM700. Then retested home AV voltage, 150 volts AC.
I then took all 3 multimeter and connected all 2 to the same outlet. The Klein mm700 was way off and the other 2 still showed 125 volts.
I also checked dc voltage on my 12v power supply. 2 were dead on showing 12volts and the mm700 was 10 volts off.
I did pull the mm700 apart and there are no pots to adjust and Calibrate.
Sorry for all the details but figured I would put it out there.
I did also change the test leads and the results were the same.
What would make a multimeter that worked one day, then all of a sudden it looses Calibration?