access menu of ref CALIBRATOR level on newer Gigatronics Spanawave power meters

[yus]

I have 2 Gigatronics meters: an older 8541C and a newer 8652C. I was always suspecting that their ref 50MHz calibrator levels are lower than the expected 1 mW = 0dBm+- power. Yesterday I had time to check.

* older 8541C cal output was about -0.3dBm after 30 min on and continued drifting down,
* newer 8652C cal output was about -0.6dBm after 30 min on and continued going down.

(From the Gigatronics user manual it is possible to see that their calibrators are not supposed to be continuously on. There is an option to keep it on. But since it is probably not supposed to be on,
the design may have not paid much attention to cal power stability.)
I did not have time to see if the output is going to level at some time. I may do it later.

I also decided to check the calibrator of an old Anritsu ML4803A which was probably not serviced in over 20 years. In contrast to Gigatronics its calibrator was almost spot on at
-0.006dBm and the output power did not drift at all.

The older 8540C series power meters ( 8541C / 8542C ) are service friendly: the user and maintenance/service manuals are available. The calibrator 0dBm ref level can be adjusted through the menu by the owner.
The newer 8650 series power meters  ( 8541C / 8542C )  are not service friendly: the service manuals are not available (see next post). The user manual still has the Calibrator Verification Procedure. It is the same as for the older 8540C series. But now instead of explaining the procedure for adjusting the calibrator 0dBm ref level the manual just says:
If any of the instrument performance characteristics are not within specifications, refer the problem to Giga-tronics Customer Service.

I almost sure that there is the same type of adjustment procedure for the calibrator 0dBm ref level on the newer meters. It is just hidden from the user.

So, my questions are:
* If you know how to activate and access the menu for ref calibrator level adjustment on the newer Gigatronics / Spanawave meters, or
* if you know where the service / maintenance  manual can be found
-- please post it.

[yus]

romal76 pointed out the answer in the thread
Gigatronics 8652A power meter

A separate service manual for the newer meters do exist openly: "Series 8650A Universal Power Meters Service Manual"
https://manualzz.com/doc/6319810/series-8650a-universal-power-meters---giga

and has the description of how to change the CALFACTOR-s. In the manual see:
2. Adjustments & Performance Tests -> 2.2 Calibration Procedure -> 2.2.3 1 mW Reference Output Adjustment