Manually adjusting HP 8673 series signal generators flatness and ALC

[benj38]

I have posted the question below to the groups.io HP-Agilent-Keysight group, but without luck, so I am hoping maybe someone here can help.
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I am in the process of nursing a venerable 8673A back to life, and I have reached the point of having to adjust the output level: it varies by over 6dB, as measured on an external power meter, at different frequencies (with the same setting/reading on the internal generator's meter).
 
The 8673A (as well as other instruments in this series) service manual calls for the use of an unobtainable service program running on an HP 85 computer in order to adjust some aspects of this instrument, in particular output level flatness and ALC.
 
Is there any way to perform this adjustment manually?
 
Is the HP 85 adjustment program used just to give the operator instructions on how to adjust trimmers, or does it send over GPIB values to be stored inside the signal generator's memory (such as DAC values)?
 
Any insights and suggestions are highly welcome!