Hi.
I have big issue with RF output level of TG3 option installed in N9320A. Please see the attached picture as well as the details described in the following:
1) The RF output looks exactly the same regardless of its settings. TG does not respond for a level change, it is always c.a. 14 dBm in peak and the difference is almost 20 dBm. I confirmed these levels with R&S power meter and Marconi 2830 SA.
2) During manual manipulation on RF out level setting I don't hear any mechanical switches.
3) When RF out level is set to auto I cannot change attentuation settings - it is always 0dBm.
4) TG reacts correctly on any change of SA frequency settings. I can set any correct (in terms of range) frequency in Zero Span mode and I see correct sweep in Full Span as well as in manual span control.
5) I can normalize TG and it works correctly - but this is not a way to normal work.
6) The screenshot is taken from the problematic machine, but I know that SA measurement is correct, because I confirmed it's correct work by CAL OUT and R&S SMIQ generator.
To be honest I don't know internals of this model and don't have service manual. Maybe some one can direct me where to start with diagnostics/repair?