[AMRadio] More Lafayette HA410 stuff


manualman manualman at juno.com
Sun Nov 29 17:26:51 EST 2009


The original ceramic mike had an extra set of contacts on the PTT switch
to do a "break before make" of the mike lead. It also shows these
contacts on the schematic.
Pete, wa2cwa
http://www.manualman.com

On Sun, 29 Nov 2009 16:10:35 -0500 "Ed Sieb" <esieb at sympatico.ca> writes:
> Ah-ha!!!  So that's why mine does that!!!  (Replaced the mic on  my 
> 460.)
> 
> Ed, VA3ES
> -----------------------------------------------------------------------
> 
> Greg Mijal wrote:
> One thing to look out for when changing mics on the 410/460 is that 
> you have 
> to use a microphone with a second set of contacts to disconnect the 
> mic 
> element from the circuit when going to receive and vice versa.  If 
> you don't 
> you will get a loud bang out of the speaker when you release the PTT 
> switch. 
> It does that because the transmitter mic audio amp is also used in 
> the 
> receiver audio and the bang is there while the relay is moving.
> Learned this one the hard way. 


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