I have been constructing a new HEKA-based Patch-Clamp setup in our lab, and there has been a weird problem with calibrating the EPC-9 amplifiers: After calibration ("Calibration successful") I have noticed that when activating the WHOLE CELL macro, which automatically sets Cslow and Rseries to predetermined values (50 pF and 20 MOhm, respectively) and subsequently automatically compensates Cslow, the values displayed in the amplifier window are immensely off: Cslow < 1 pF and Rseries > 100 MOhm.
The discrete values are not reproducable, every time I activate the WHOLE CELL macro they are off but with varying values, sometimes Rseries cannot even be estimated (".... MOhm"). Calibrating the amplifiers with different model cells has brought no improvement.
Visually, the test pulse displayed in the Oscilloscope window is completely normal.
Discussing this with HEKA support has thus far not brought any solutions, so I wonder if anyone else has had similar problems and if yes, what you did about it.