[Elecraft] No speaker audio

[Geoffrey Mackenzie-Kennedy]

David,

I am using a 3.5 mm jack / switch made by Schuter www.schuter.com , their 
part number 4302 - 2310 which is the insulated version. I happened to have a 
spare new one which I had purchased in Luxembourg, but I believe that 
Digikey carry many of Schuter's items.

Apart from being more robust than the existing headphone jack, the internal 
switches are more versatile there being one switch on each of the ring, tip 
and sleeve 'connections'. Schuter sells a plug designed to mate with this 
connector, but as yet I have had no problems when I have had to use a 
'standard' 3.5mm stereo plug.

Sorry no pics, but I mounted the jack on the rear panel of the K2 as high as 
possible above relay K1 (on RF Board). Although this is perhaps not the best 
place for the new jack I did not want to get too close to the Tx driver and 
PA to avoid possible RF problems of various types. Having said that my 
KPA100 just above has not caused any visible problems. I dispensed with R35, 
R36, C105 and C106 and used a length of small diameter 2 conductor sreened 
pair to bring the audio 'Hi' and 'Lo'  to the new jack. This 'cable' lives 
high up on and fixed to the inside of the K2's left hand side panel. To use 
the internal speaker you would want at least one extra wire in the 
connecting 'cable' to go back from the new jack to the speaker circuit trace 
near the existing headphone jack. I would not use the screen for the audio 
'Lo'.

If I was going to do it again I just might put the new jack near the K2's 
antenna jack and bring the audio from the area of P5 on the right hand side 
of the K2. Since putting in the new jack I have found that any additional 
objects 'seen' by the Reference oscillator, VCO and BFO on the left can 
result in additional problems with receiver birdies and Tx spurs, including 
the notorious 7183 kHz flutter. To do this would require a permanent short 
between the junction of R35 / R36 and the speaker track going off to P5, 
cutting this track close to P5 for connection to the new headphone jack, 
with the returning speaker circuit connected to P5.

I hope that this is useful.

73,
Geoff
GM4ESD


----- Original Message ----- 
From: "David Wilburn" <dave.wilburn at verizon.net>
To: "Geoffrey Mackenzie-Kennedy" <gmk at gm4esd.fsworld.co.uk>
Cc: "Kirk Brown" <kbpayh at gmail.com>; "Elecraft Discussion List" 
<elecraft at mailman.qth.net>
Sent: Saturday, January 13, 2007 1:39 PM
Subject: Re: [Elecraft] No speaker audio


> Any pics of how you mounted and wired it or the part number and vendor of 
> the part you got to replace it?  I'm planning a K2 build soon as I sell 
> some radios.  So I was trying to get the pieces in place from the start.
>
> David Wilburn
> dave.wilburn at verizon.net
> K4DGW
>
>
>
> Geoffrey Mackenzie-Kennedy wrote:
>> Kirk,
>>
>> Sounds as though the internal switch in your headphone jack has failed, 
>> and the only practical fix I believe is to replace it.  Since 2003 the 
>> switch in the original headphone jack and its replacement in my K2 have 
>> failed, and I now use a robust headphone jack mounted on the rear panel.
>>
>> 73,
>> Geoff
>> GM4ESD