Help with HD-1410 Keyer

[William K . Mabry]

Joe and group,
The HD-1410 was designed to automatically switch from a negative key line to
gnd for grid-block keying or positive line to gnd for solid state rig keying.
BTW the heatsinked transistor is the series pass device for the 5 VDC power
supply.
Heath recommended that, for keying solid-state rigs only, one should jumper
across D5 and R27 to provide very close to gnd output during keydown. This,
by the way, assumes some current-limiting resistance in the rig's key line (
pull -up resistor ).
Q7 is, effectively, rendered inoperative by this mod and may be removed if
desired ( probably should be removed ).
Check and see if this mod has been performed on your unit.
73,
Bill

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