Performed some functional tests of the 7A16A, 7A18A, and 7A26 plug-ins and I have the results. When I get a new to me functional scope, or in this case plug-ins, there are certain basic criteria that I look at and if they pass I consider it “calibrated”. There is no way I can do a “by the book” calibration because I don't have the proper equipment and in reality unless there's been major repairs or some dimwit has been in there twiddling pots it really isn't necessary. The criteria I consider important are:
Vertical gain. Example: does a 0.5V p-p waveform appear as such?
Trigger. Does the waveform trigger and is it stable?
Compensation. 1KHz square wave flat with no peaking or rounding?.
High frequency test. Does a 1MHz and 10MHz square display accurately?
Sweep speed. Is it linear and accurate?
Trace quality. Bright and sharp focus?
In the case of these plug-ins only the first 4 apply. The sweep and trace are determined by the mainframe and the timebase plug-in. Here's my test set up. The Feel Tech function generator is for the 1KHz square wave. The Heath IG-4244 Scope Calibrator is for the 1MHz and 10MHz square. The 2465 is powered up and on standby in case something don't look right.
So how did these plug-ins perform?
Vertical gain: All 3 plug-ins were dead nuts.
Trigger: Solid Trigger on all 3.
Compensation: The 7A18A and 7A26 are perfect. The 7A16A has both peaking and roll off issues. While attempting to adjust it the trace is dancing around again. I guess I'm going to have to pull this attenuator assembly apart and give it a more extensive cleaning. Luckily it's easy to get to. Into the project cue.
High frequency test: Both the 7A18A and 7A26 are OK. The 7A16A because of the problems above shows extensive peaking at high frequencies.
This is MY rabbit hole.
As soon as Inverted18650 gets back to me with a shipping cost I'm going to have a 7704A to play with.