I have one question and no one can seem to give me a straight answer, all I would like to know is: for my JVC; model KW-R930BTS car stereo does the power need to be on to see the clock?
The manual for your radio says there is a setting to control whether the clock is displayed when the unit is off.
It shows something like this (which was from a PDF I can't link to). See the CLOCK DISPLAY section.
You can search for and download the clearer PDF quite easily.