We are currently using A7r5 cells and are attempting whole cell recordings. We are using PatchMax 100 which is a scaled down verson of the actual electrophysiology rig so we are not able to see the cells as we patch. We are able to get good gigaseals but it is impossible to break the patch open no matter how much suction is applied. Has any one else observed this? We are open to any suggestion at this point.