[AMRadio] More Lafayette HA410 stuff

Greg Mijal bluebirdtele at embarqmail.com
Sun Nov 29 15:54:08 EST 2009

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. Still have my HA 410.
Kinston NC
----- Original Message ----- 
From: "manualman" <manualman at juno.com>
To: <k5xu at comcast.net>
Cc: <amradio at mailman.qth.net>
Sent: Sunday, November 29, 2009 2:50 PM
Subject: Re: [AMRadio] Lafayette HA410 Question

>I commented on your similar query back in September 2008 at this link:
> http://www.mail-archive.com/amradio@mailman.qth.net/msg21734.html
> All versions of the HA-410 and HA-460 used a 4 pin male connector for
> mike input. However, depending on the previous owner(s), changing the
> mike connector on the rig from male to female, was sometimes easier then
> changing the mike connector on the mike cable. Overall dimensions of all
> HA-410's and HA-460's were the same. I know of no physical changes to the
> length, width, height throughout their life-cycle. The power transistors
> and the back cover for them varied over the years. Some units came with a
> smaller black cover with four 2SB-425 transistors mounted behind them.
> Some units came with a larger black cover and had either four 2SB-377,
> 2SB-425, or 2SB-472 transistors mounted behind them. The most significant
> difference between the 2 models of the HA-410 and the 2 models of the
> HA-460 was in the audio output tubes. One version used a pair of 6GW8
> tubes and the other version used a pair of 6BM8 tubes. Sockets were also
> wired differently because pin numbers weren't the same. There was also an
> addendum to correct a wiring error in the earlier models of both
> HA-410/460 in the DC to DC converter.
> Pete, wa2cwa
> http://www.manualman.com
> On Sun, 29 Nov 2009 10:38:00 -0600 "Mike Duke, K5XU" <k5xu at comcast.net>
> writes:
>> Apparently there were at least two versions of this 10 meter rig.
>> What I assume to be the later version is physically smaller than the
>> earlier one.
>> If you own the smaller model, and have a schematic that reflects
>> what's inside the cabinet, please e-mail me off list. I need to ask
>> some questions about the audio section.
>> If you aren't sure which unit you have, the larger one has the power
>> transistors mounted along a section of the back panel, and has a 4
>> pin
>> female microphone socket. The smaller one has the power transistors
>> grouped together behind a cover on the back panel, and has a 4 pin
>> male microphone socket.
>> Mike Duke, K5XU
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