I am using Multiclamp 700B and pCLAMP10 for my extracellular recording experiments. In current clamp mode, but with I=0, I use a gain=1000, and Feedback resistor Rf=500 Megaohm. Under these conditions I get an OVERLOAD error in Multiclamp Commander window. with no traces a all in pCLAMP or traces with very extremely high noise levels. However the same conditions had been working well in another setup having the same instruments. I have verified this setup using the Model cell (Patch 1-U Model cell, Bath configuration). After a value of gain more than 100 in current clamp mode, it shows OVERLOAD. Also, in Voltage clamp mode, with Rf=500 Megaohm, it shows overload even with a gain value of 10. I am not able to identify the problem. Please give me some suggestions.