[Heathkit] Heath Apache BFO questiom

[manualman at juno.com]

Make sure you're using the Mohawk schematic. The Apache is the
transmitter.
Pete, wa2cwa

On Sun, 21 Oct 2018 23:41:33 +0000 (UTC) John King via Heathkit
<heathkit at mailman.qth.net> writes:
> I have a Heath Apache with a VERY NOISY BFO control. The BFO control 
> has a shaft that goes into a box on top of the chassis. Out of the 
> bottom of the box housing the control , two wires through the 
> chassis to the a tube socket
> When I turn the BFO knob a loud scratchy noise is made in the audio. 
> My question is: What is inside the box that is turned or switched by 
> the shaft going to the box. Is it a variable capacitor or rotary 
> switch???  I don't want to go into the VFO box until I know. The 
> schematic is not clear about what is inside the cox.
> Your input will be greatly appreciated.
> 73, John, K5PGW