Hey, my brother-in-law dropped off his Fender twin today for me to get working. I'd like to surprise him and clean it up a bit. It is missing the back panels and last he remembered "didn't work". I'm a Marshall guy so I know squat about these, but to me it looks like a late 60's/ early 70's unit. It say CBS on the back panel, has three 12AX7 and two 12AT7, a fender logo with the double underscore and serial # B 106**. I have some questions/ favors to ask. 1.) Can anyone send me a dimensional sketch of the back panel(s)? I have some 1/4" plywood I could cook some up with. 2.) Can someone sell me some scrap tolex to cover them? 3.) Are there mods I can do to improve the sound (blackface, mid boost, etc.) As I am quite ignorant on these things, I would be interested in how to make this amp more flexible without hacking it too bad. 4.) Have people tried post-phase inverter master volumes on these? I really dig them in my Marshalls. Can they replace the standard MV? 5.) One of the knobs is cracked, anybody want to sell me one without requiring me to "assume the position"? I'd appreciate any help!