The PRO-96/2096 does not have analog AGC. If you want the Analog AGC on the 996, go to settings\Set audio AGC and turn the Digital off. Press scan to return, then press Func + Vol/push light to access the analog AGC settings.
Try pressing and holding the Func button until it beeps twice, this will help you select the gain or threshold, etc., then release the Function hold by pressing Func, once you are where you want to be.
Turning the Func knob left or right when in the mode you want to adjust, should change the number up or down, and change the setting results.
Don't forget to go back and change the digital AGC to on in settings once you are finished with the analog changes, or you won't be using the digital AGC.
If you are getting the machine gun sound you may want to try adjusting the automatic digital settings. This is not in the hidden settings. Turn the 996 off, then on. Press Func + Vol\Push light to see the automatic digital settings. the default setting is 8 Auto. I use 6 and 7 on most of the digital P25 and mixed mode systems. If you watch the bottom line to the right of the "T", you should see the numbers change as you hear the P25 audio. When changing the auto number watch to see if the T numbers are close to the numbers displayed, the less varaition you see and the better the voice sounds, then make note of the auto number and leave it there.