Today I put the FSS frequency box back into the 1Y1 rack.
To power it on, I turned on the 24V and 15V Sorensen switches in the same rack.
The PMC crystal board in the same rack should not be affected (it runs with 10V), but, to make sure it was not powered, I disconnected it from its crate. Since the board was disconnected from the EOM for the PSL table's upgrade, I wanted to avoid having the RF output floating.
We just have to remember to plug it back in, when we need it again.