[Amps] SB220 Mods

[K0SN]

Hi To The Amps Group-

I am working on doing the Rich Measures vacuum relay and Electronic Bias switch mod to an SB220. Possibly someone here on the reflector is familiar with the setup.
Rich's diagram shows the collector of Q1 connected to the Filament Transformer center tap (contact 8 on the original Heath relay), and the emitter to -HV (contact 5). My question is where does the red conductor coming from D16 to contact 2 on the original Heath relay now connect to?
I have posed the question to Rich and received no response so hoping someone here can give some input. 

Thanks for any input.
73
Tom K0SN
Porterfield, WI