[Johnson] keying

[Charles Ring]

I'd like to use my Novice transmitter from 1963, a Johnson Adventurer, 
with my Globe V-10 VFO and/or my WRL 755 VFO. The Adventurer has rather 
heavy cathode keying current, over 120 mA at over +150 volts, and draws 
a spark on my bug. Either VFO has much lower positive keying voltage and 
current. I'd like to use my HA-5 T.O. keyer on this combination without 
ruining its sealed mercury-wetted contact keying relay, and without 
another electromagnetic relay. Thinking that this has been solved long 
ago, where can I find a circuit to accomplish this? The Adventurer has 
no cutoff bias so it puts  out a lot of diode noise if keyed with no 
drive. I have no objection to using modern techniques with my old gear.

-- 
*Charles Ring W3NU*