[R-390] R390A Turns Counter BFO option

[Steve Hobensack]

In the Navy Security Group, most maintainence men would simply mount the bfo knob a little shallow, so the stop tangs will not meet. This was done on R-390's used for TTY service. It was pretty easy to return the bfo knob back to home (455 khz) by tuning the receiver away from any signals, moving the bandwidth to 0.1 khz, and zero beating the noise. Otherwise one could be an entire rotation away from the zero mark.
----Steve    N8YE
 
Date: Sun, 13 Mar 2011 15:52:09 -0500 (CDT)
From: nryan at mchsi.com
Subject: Re: [R-390] R390A Turns Counter BFO option?
Cc: r-390 at mailman.qth.net
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Fellow Mavens,
 
The BFO range can be expanded by removing the rotation limiting tang under the BFO knob. Be advised that doing so risks damage to the very fragile powdered iron core inside Z502. Turn it too far and it will break.
 
A broken powdered iron core sometimes can be repaired with careful application of JB weld. Check that the repaired core is straight and true inside the coil.
 
If a MicroDial is added, zero it on 455 kHz and don't force it against the core's travel limit.
 
73 de Norman, KG4SWM