second ma meter burned out EPM-3D100MAB

[sshwarts]

Marco:
I had the first digital milliamp meter go out after quite a few hours of use (I sent you a picture of the burned out diode). The second one I bought from you failed within a few minutes of use in the same way. Is it possible that these were shipped to you with the wrong resistors set for the kind of voltages expected? In looking at the resistors installed and the table screen printed it would seem so but I'm not sure. Would like to know before I go order now a third one!

The meter is wired using an isolated 5V supply and on the low side of the circuit (tube to ground).

[NickWL]

I had the same problem - lost two before settling in comfortably with the third one. Good insulating of the wiring and pins seems to have been the cure.
One just died, the second looked as though it had had 27kV pushed through it backwards!
I've now got a spare and nowhere to use it!
Ni ck

[Tech_Marco]

Marco:
I had the first digital milliamp meter go out after quite a few hours of use (I sent you a picture of the burned out diode). The second one I bought from you failed within a few minutes of use in the same way. Is it possible that these were shipped to you with the wrong resistors set for the kind of voltages expected? In looking at the resistors installed and the table screen printed it would seem so but I'm not sure. Would like to know before I go order now a third one!

The meter is wired using an isolated 5V supply and on the low side of the circuit (tube to ground).

Please double check the "Negative return". If it is firmly connected, the chance that happen to burn a current meter is very low. If two in a row, then it is very odd.

Send me your order# and let me ship you another one.


Marco

[sshwarts]

Thanks Marco, it was order # 204153

I would think that if there was not a good path to ground through the internal shunt then the tube would not fire (with an isolated power supply), would it?

Scott

[Tech_Marco]

Scott:

FYI, if the ground is not connected, the Positive of the PSU will fire up in air and the spark (arc) will drive through the meter and kill it. The tube will not fire though.

So, make sure that the negative wire is firmly connect to the digital meter and the plug is firmly inserted.


Marco

[NickWL]

I'm guessing that's what happened to (two of) mine!
Nick