K2 - No Audio Except during Menu - updated

[Zac Brown-2]

Hello,

After reading thru the troubleshooting section of the manual, I reheated the solder joints at Q6 & Q7. Unfortunately, nothing changed. It is as if the K2 is always muted, except when in menu mode after "Atu" is selected. I read thru some of the previous threads on the list related to K2s being stuck in mute. Checked U6 pin 17 - it's stuck at 0 V. Not sure how to progress at this point.

Zac
 
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[Don Wilhelm-3]

Zac,

Check the voltage on U6 pin 17 while in the menu (at a time you say you can
hear audio).  If it goes to a higher voltage, then suspect the MCU itself,
but if it stays at 0 volts, look for a short on the '/MUTE' signal line.  I
believe the only parts involved in this signal line are U6 pin 17, R17, C23
and the gates of Q6 and Q7.

Remove the MCU and look carefully to be certain pin 17 is properly seated on
the socket - not sticking out or bent under.

You do have the jumpers R18 and R19 in place on the Control Board do you
not?

Also look for unsoldered connector pins on the connectors vetween the
control board, Front panel and the RF Board.

I am mystified by your report that you hear audio when you have the ATU menu
active - I have found occasions when something like that appeared to be the
case, but an unsoldered connector was making contact when pressure was
placed on the boards, like when you press the menu button - don't overlook
things of that nature.  The most likely problem is an unsoldered or poorly
soldered connection.

73,
Don W3FPR

> -----Original Message-----
> From: [hidden email]
> [mailto:[hidden email]]On Behalf Of Zac Brown
> Sent: Sunday, July 17, 2005 6:03 PM
> To: [hidden email]
> Cc: [hidden email]
> Subject: [Elecraft] K2 - No Audio Except during Menu - updated
>
>
> Hello,
>
> After reading thru the troubleshooting section of the manual, I
> reheated the solder joints at Q6 & Q7. Unfortunately, nothing
> changed. It is as if the K2 is always muted, except when in menu
> mode after "Atu" is selected. I read thru some of the previous
> threads on the list related to K2s being stuck in mute. Checked
> U6 pin 17 - it's stuck at 0 V. Not sure how to progress at this point.
>
> Zac
>
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[Brian Mury-3]

On Sun, 2005-07-17 at 17:02 -0500, Zac Brown wrote:
> It is as if the K2 is always muted, except when in menu mode after
> "Atu" is selected.

I had the same problem when I built my K2. It was caused by pin 1 of the
control board processor having bent over (instead of going into the
socket) when I inserted the IC into the socket. It was touching pin 2.
Straightening the pin and reinserting the IC solved the problem.

I made a few posts to this list as I was working on the problem. The
thread starts here:

http://www.ac6rm.net/mailarchive/html/elecraft-list/2004-06/msg00352.html


--
73, Brian
VE7NGR
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