[AMRadio] Another question, this time Desk KW

[Robert Nickels]

On 7/27/2021 10:31 AM, CL in NC via AMRadio wrote:
> According to him, the only issue is now, when he turns on the filament power, the B+ comes up also, without keying it.  Before I download a schematic and bring out the Ouija Board, is anyone familiar with this problem and knows exactly what is wrong?

A switched 110VAC voltage from the exciter is used to activate the plate 
relay via pin 8 of the octal connector on the Desk Kilowatt.   With a 
Ranger this voltage is normally acquired from the top pin of the antenna 
relay connector on the back of the Ranger (i.e. crystal socket).   This 
line should have 110VAC on it only when the Ranger is keyed in TX mode, 
exactly like you'd use to energize an antenna relay.

Have your friend disconnect that wire and you'll know whether the 
problem is in the Ranger or in the Kilowatt.   The plate relay control 
voltage from pin 8 is routed through the interlocks, overcurrent 
protection relay contacts, etc in the desk so if it still pulls in with 
the external keyline disconnected, you'll need the schematic and to pull 
the pedestal out for some floor-level troubleshooting.

73, Bob W9RAN