[Heathkit] DX-35 help needed

[WØQFC]

Looking at the schematic, the filament wiring for the 12BY7(buffer) shows 
that pins 1, 3, 4 & 5 are tied together and go to "X" on the power tranny; 
also goes thru a 47K to pin 2, thru a 470 to the switch & 40M coil, thru a 
27K to pin 8 of the 12BY7 oscillator and thru a 47K to pin 7 of the 
oscillator.

Questions:

 Why would the filament be tied to the cathode and grid of the buffer?
 Why would the filament be tied to the grid and plate of the oscillator?
 How would the oscillator get it's plate and screen voltages?

I am unable to dip the final and I believe it is because there is no drive 
to the final grid because there is no plate and screen voltage on the 
oscillator..

Your help and thoughts will be appreciated!

TIA
Gene, WØQFC

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