Hi,
Today I tested two HP 3457A multimeters, I saved them from their journey to the garbage dump. I studied the two excelent youtube video's from this device.
We've got +220V so I started with the first on 220v as we do with al our devices. First I did a successful the internal test. Then I checked the numbers of calbration (35).
So, I was very happy with my new device ..until I pushed some buttons OHM, DCI ACI and suddenly a sissy sound, a lot of smoke , terrible smell and a little panic!
I dissabled the power, and checked the fuse at the rear, but that is still intact! I can see a burning spot at the rear just above the power inlet. I didn't power it up again cause I first want to check without the cover what's dammaged inside.
Now let's check if the other 3457A is working. Internal test OK, calibrationumbers: 54 Do the buttons
work???.....OMG
same thing happens smoke and terrible smell ...but no damaged fuse?? I don't know it's important to tell but I don't have main earth in this room
Can someone please explain what I'm doing wrong?
Kind regards,