Here are the resultant waveforms from my post last night showing excellent compensation.
First, as a control here is the 1MHz square from the Heath IG-4244 Scope Calibrator on the 2465. The rise time of that square is approx 1ns.
As an additional control here is the same waveform on the 7603N with a 7A26 plug-in. This plug-in did NOT require any adjustments or compensation. The settings on the 7603N are the same as the 2465.
Here is the 7A15A. This had a noisy attenuator switch deck which involved removal of the attenuator blocks and partial disassembly of the switch assembly to clean it. So the compensation was way off after assembly and it came right in with the procedure I described yesterday.
Finally, the 7A16A. This one was a real PITA. No only did it have a noisy switch deck requiring disassembly but it also had a defective 2X attenuator block. So this compensation was way off too. Fixed after doing my procedure. But this plug-in had another surprise. Upon application of the 1MHz square there was approx 2 minor divisions of peaking on both top and bottom of the waveform. The spec calls for no more than 0.6 minor division peaking. This is a wide band (225MHz) plug-in and there are 8 HF adjustments (4 trim pots, 4 trim caps) on the amplifier board that have to be adjusted in a specific order. But this plug-in only had 6 HF adjustments so apparently there was a revision and the manual I have is no good. But I got lucky. I carefully tweaked each control and I found the trim cap that with just a minor adjustment eliminated the peaking. So now this plug-in is dead nuts too.