[Heathkit] HP-23 Mystery 6.3 volt Green Wire???

[OTAKEBI at aol.com]

OK, I have another mystery on this HP-23 I am modifying.
This if for the list and for Ed if he reads this.
I have gone nuts today trying to find the green wire from the transformer  of 
my HP-23.
This is the wire that should go to lug #8 so as to supply 6.3  volts to the 
filaments.
Nothing is connected now to lug #8 now.
I can find the green-yellow that is connected to lug #6 that provides  12 
volts for filament
I have checked all the wires coming out of the transformer and no sign of  
green.
Now according to the paperwork I got a hold of the HP-23 and HP-23A have  
provisions for 6.3 volts and 12 volts.
Now, I am thinking along the line another HAM changed the transformer but  it 
looks original.
Schematic shows a green wire to lug #8 and construction manual  shows to 
connect green wire to lug #8 for 6.3 volts filament.
I am probably going to have to add a 6.3 outboard filament transformer  to 
avoid core saturation anyway when I modify the 300 volt +LV to 275 volt  using a 
Darlington type circuit with diodes of 91 volts in a string of  three and a 
transistor for use with a Collins 
KWM-1. 
After doing the mod I will be able to remove the choke for ripple out of  
circuit and the 6.3 filament transformer will fit just right in its  place. 
But, the mystery of the missing green wire from the transformer really bugs  
me.
Would have made life a lot less complicated if I had 6.3 volts right off  the 
bat.
Any help with this Heathkit mystery?
Thanks,
Dan/N4VET