[Hallicrafters] HA-1 keyer modification

[Waldo Magnuson]

Thanks fellows.  The HA-1keyer was very easy to modify to accept both 
straight key and paddle (and have sidetone for both).  I mounted a jack 
at the back and a wired a 47K ohm resistor from the jack tip to pin 4 
of the mercury relay - that was it.  The key plugs into the back jack 
and the paddle into the normal front jack.  Works good, there is -12 
volts at the key but through the 47K so should be safe enough.  Thank 
you all for the advice and help.
73,  Skip Magnuson   W7WGM