We have used two of these amps for many years. I am trying to replace the tube (4CX250B) in one of them. This is my first time doing this. I have replaced the tube with one I think is good that was stored in the repeater. The GE instructions are typical, transmit at low power into the output of the amp, peak the grid current with Grid and Filter controls then null the grid current using the neutralizer control. The problem: after peaking the grid current with Grid and Filter, the neutralizer control will only further peak the grid current, the nulls occur at both ends of the control travel; there is a definite peak in the middle of the control range instead of a null. Any idea what would cause this condition?
Bill
