[AMRadio] NC270 Muting

[Bob Peters]

Thanks Mitch and all...Just have to do some rewiring...Thanks  will get it
done this weekend...

Bob

-----Original Message-----
From: amradio-bounces at mailman.qth.net
[mailto:amradio-bounces at mailman.qth.net] On Behalf Of C.L. Mitchell
Sent: Thursday, April 07, 2011 8:27 PM
To: amradio at mailman.qth.net
Subject: Re: [AMRadio] NC270 Muting


Got a chance to look at a schematic for the NC-270.  The 'standby/receive'
switch opens the +145 VDC line from the power supply, which effectively
shuts down most of the radio.  The other section of the DP switch shorts the
rear apron terminals.  You could change the wires going to the rear
terminals to across the section of the switch that controls the low B+ line
and switch it with an external relay, etc; leaving the 'standby/receiver'
switch in 'standby' to use external switching.  The drawback to this is 145
VDC floating around on the control wiring.  I personally would, and have in
some of my receivers, install a small low voltage relay in the National and
use it to control the low B+ line as above and control the relay with
external switching.  You can always pick up low voltage from the filament
winding on the power transformer.  Hope this helps.
 
73,  Mitch
K9PNP
 

> From: rwpeters at swbell.net
> To: boatanchors at mailman.qth.net; boatanchors at puck.nether.net;
amradio at mailman.qth.net
> Date: Thu, 7 Apr 2011 09:56:43 -0500
> Subject: [AMRadio] NC270 Muting
> 
> Hi Guys... Have a Natoional 270 and need to know how to mute it... It has
> relay screws in the rear but when shorted do not work...
> Any ideas????
> 
> 
> Very Best 73's
> Bob Peters
> W1PE
> 
> ARRL, QCWA, AM FOREVER
> 
> Money is only temporary, Radio is forever
> >From The Old Dog
> 
> 
> 
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