[Eliot Ness]

As suggested, I measured resistance in the following places and here are results.

Filament of 80  (6&7)--->CenterTap of 9&10  = 0
Center Tap of 9&10 (-  ---> Chassis  = 307k
Plate of 80  9&10 --->Chassis  = 521 and 506k
Center Tap of (3&4)  (5) --->Chassis  = 0
Filament of 80  (6&7)----Chassis  = 0  ( 10uf EL cap attaches here)
Filament  (3 & 4) ---Chassis  = 3 & 6k

Center tap 8 should read ~ 325 ohms to gnd (through resistor 30).  But the bigger issue is 0 ohms from the filament taps (6&7) to #8.  Unless I'm overlooking something you need to figure out what is shorted here.  I'd start by taking good notes/pictures and then disconnecting things to see what is shorted or mis-wired. 

Do this with the 80 removed and I would probable disconnect the power transformer also so I could check for shorts.  I suspect something has been mis-wired, but you'll have to double check all wiring against the schematic to verify.