V-4 - One of my Tbar faders on my V-4 isn't doing any fading or isn't fading fully. I can move it, but it won't switch between buses properly.

You need to re-calibrate your Tbar. In the Menu, go to SYSTEM. In there, you will see FADER CALIBRATE for A, B, C and D. If it's your SD fader that is not right, select FADER CALIBRATE A > ENTER. Move the Tbar to BUS A. Select YES in the Menu and press ENTER. Then escape and select FADER CALIBRATE B. Move the Tbar to B BUS and select YES and press ENTER. Your A/B Tbar should now be correct. For the HD T-bar, simply use the C and D CALIBRATE in a similar fashion. Refer to page 64 of your owner's manual for details.