Hello, I am plagued for some time by a loose connection (resulting in poor directivity) in one of the directional couplers in my 85046A test set. I want to determine the cause of the malfunction and had to remove the coupler from the test set to open it. The lid is secured by eight screws. Unfortunately, the lid cannot be opened after removal of the screws, because it has been sticked. Does anyone have an idea how the lid can be opened? Perhaps by heating?