Question for the auld timers: does this unit have only composite output or something else, like Y/C or component? I ask because I see three output BNCs with a "Comp/Non-Comp" switch on the back panel. I'm thinking of acquiring one of these to stabilize my VO-9850.
Yes and no.
The normal input is composite video as is the normal output. The switch you refer to doesn't switch the outputs to component but will switch between composite and Non-composite. But the large multi-pin connector at the left is designed to take the input from a U-Matic deck as it's input. If you can find a matching cable and the VO-series deck has that connector on the back (I know the BVU series had it but not sure about the VO series) you can input your tape machine that way. Much cleaner than going in composite. Output will still be composite.
This is a very old unit. Make sure it's in good working order before investing anything in it. Caps dry out and components fail over the years. If you have to have something on the output of a U-Matic, you might consider a newer framesync type TBC. They are pretty cheap now and would probably look a lot better than a 20-plus year old TBC.