BTW the P-6157 seems non-standard
Your link to the stancor catalog contains more info than my old paper catalog. Unfortunataly mine is listed in neither.
If only the base of the 866 is cracked, the tube is probably still good. Love those old things and watching the blue glow change as you operate.
Nope, the glass was actually cracked.
The good news is that I haven't gone too far in disassembly to put things in reverse. I took my copy of Radio Handbook 8th edition along with me to work last week. Getting a little reading done on choke inputs.
Still not knowing the rating on the x-former bothers me. If I do decide to completely convert it I have another transformer upstairs. Just abandoning this x-former because I don't know what it is seems a waste though. I have a Gates 1850/CT 1A CCS that would be overkill but definatly enough to feed 4 X 572b's