I am in urgent knowing what is wrong with my amplifier (HEKA EPC 10 USB). So thankful if you guys could give me a hand.
I met a problem when using a HEKA EPC 10 USB (with patchmaster) which belonged to another staff in the lab previously.
using test pulse (default setting), when the pipet of the probe dipping into the bath solution, the voltage offset increased a lot (even over 200mV).
If configuring the Gain below 0.02mV/pA, I may see the current signal. I use the "auto" button of the voltage offset section, patchmaster keeps voltage offset as 0mV. I have to manually configure that. In addition, the signal drift randomly up and down.
All setting of patchmaster is default.
However, if I use the model circuit/model cell, there is no any problem. amplifier is grounded, microscope is grounded.
what I tried
re-prepare fresh agar bridge
re-coat silver ware
filter bath solution
use bath solution as pipet solution
directly dip reference wire into the bath solution without using agar bridge
without using glass pipette, directly dip silver wire into the bathsolution
May I ask what is the potential problem that I did not check?