Hello all,
I just bought also a 3400a, and found a strange behaviour, in the 1mV / 3mV range of the meter.
When I apply a frequency, close to the line frequency, that is also used for the internal chopper amplifier - here in germany it's 50Hz - the pointer of the meter is oszillating a lot. In the 1 mv range up to +/- 0,25 mv. When I change the frequency away from the line frequency, this phenomen decreases. The phenomen is alo present on the 1st harmonic, so at 100Hz, but not that mutch.
In the 10 mV range this phenomen is not so mutch present. From the 30mV range and higher, it is no more visible.
Is this normal behaviour or is there something defective in the device?
The RMS reading of the 3400a is very simmilar to the measurement of my TEk oszilloscope.
Kind regards
Ghido