K1 no audio

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K1 no audio

wingman67
I have recently built up a K1 to the point of the receiver alignment (page 36, 7 "Alignment and Test, Part 1").  Up until this point all of my test points have been successful, voltages correct, etc.  When I power on the K1 I get the correct LED test pattern and then the E27/E42 error messages that are expected.

However, when I begin going through the steps on page 36 all is well until I get to the point on page 37 where I turn on the sidetone.  I access the stl menu item, press-and-hold Menu and it comes up with 8 by default.  I can tap up and down, exit the menu and go back in and the eeprom remembers my settings.  I can turn the K1 off and back on, go back into the menus and access the stl menu and it remembered my setting.  The only problem is I hear nothing, either on the headphone jack or on the external speaker connector.  Everything else on the transceiver seems to function properly including turning on and off the attenuator, rit/xit, etc.  Just no sound of any kind.

Just for grins I went ahead and installed the filter board to test that portion of it and all of that worked perfectly.  The relays switch bands and the display shows everything properly, no problems and of course with the filter board installed the E27 goes away.  With the filter board installed, I still hear nothing when I access the stl menu to tap up or down the sidetone level.  I also hear absolutely no hiss.

Removing the filter board and powering back on I am back to the expected E27 and E42.  

It appears that everything else works completely as expected, considering the point at which I am in construction.  The only issue is I have no audio which also means I hear no sidetone when I access the stl menu.

I've spent many hours (roughly 7 as of this moment) going over both the top and bottom of the RF board with a magnifying glass looking at each and every connection and solder joint.  I did go ahead and re-flow several that I thought maybe were suspect and re-soldered some others just to be safe.  I paid special attention to the P1 connector and ensured each and every pin is well soldered.

I then started working through the audio chain, starting from the front-panel and working my way to the RF board.  

I verified:

1.  I hear sidetone on P1 pin 2
2.  I hear sidetone on Q11 drain (I had heard that could be a known issue, but it wasn't)
3.  I hear sidetone on U3 pin 5
4.  I verified source and drain are not shorted on Q10
5.  I verified source and drain are not open on Q11

It seems like audio is getting to the amp stages but the K1 is completely quiet (and I mean quiet, with absolutely none of the normal hiss you would expect to hear).  I have absolutely nothing coming from the headphone jack or the external speaker connector.

Any ideas on what/where else to check and see where my sound has gone?  Now I am assuming, based on pages 36 and 37 of the manual, that I am at the point where when I access the stl menu that turns on sidetone and that I *should* be able to hear it.  If that is correct, the K1 is completely silent.  Thought I'd pull back and see if anyone else has had a similar issue or has some insight.

Thanks.

John
John Hines
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Re: K1 no audio

wingman67
Ok I now have audio.....I can hear "hiss" fairly loudly as well as strong sidetone when I go into the stl menu.  I replaced C11 and audio sprung to life.

I proceeded to wind L1 and installed it, then re-installed my filter board and now I get the E42, "No VFO."  I can go into the menus and successfully have the K1 see the two bands that the filter board support and can switch between them, no problems but I can't proceed further due to the E42.  

The audio I hear is strong but is of course just "hiss" since the VFO isn't working yet (therefore I don't hear anything other than the hiss and hence the E42).

I was told that sometimes D17 installed backwards could cause this.  I checked its orientation and it is correct.  I also checked soldering around some of the other caps that some have said can be an issue and reflowed them just to be safe.  

I am continuing to try tracing out the issue but any ideas on where else I might look, on the offchance anyone else has encountered this same thing?
John Hines
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Re: K1 no audio

wingman67
This post was updated on .
In reply to this post by wingman67
Problem solved, thanks for the pointers Don!  In checking the RF board and filter board over and over, I disassembled the front-panel so I could get to the FP board again, resoldered pin 10 on J1 since it didn't look as good to me as it could have been and then, as I went over everything I found an unsoldered leg on R11.  I am normally extremely meticulous when it comes to building but this one got past me!  Soldered that leg, re-assembled the FP assembly and hooked it back up to the K1's RF and all is well.  VFO works and all tests pass.

I think maybe I just need a larger magnifying glass.  :)

So now I'm ready to start working on the TX section of the board.

Thanks again Don.
John Hines
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Re: K1 no audio

kg9hfrank@gmail.com
John, great to hear.
Most of us have graduated to a 6” loop that is lighted.
Frank KG9H

> On Jan 11, 2016, at 10:48 AM, wingman67 via Elecraft <[hidden email]> wrote:
>
> Problem solved, thanks for the pointers Don!  In checking the RF board and
> filter board over and over, I disassembled the front-panel board again,
> resoldered pin 10 on J1 since it didn't look as good to me as it could have
> been and then, as I went over everything I found an unsoldered leg on R11.
> I am normally extremely meticulous when it comes to building but this one
> got past me!  Soldered that leg, re-assembled the FP assembly and hooked it
> back up to the K1's RF and all is well.  VFO works and all tests pass.
>
> So now I'm ready to start working on the TX section of the board.
>
> Thanks again Don.
>
>
>
> -----
> John Hines
> --
> View this message in context: http://elecraft.365791.n2.nabble.com/K1-no-audio-tp7612521p7612533.html
> Sent from the Elecraft mailing list archive at Nabble.com.
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Re: K1 no audio

wingman67
lol!  Not a bad idea Frank!  :)

John
KD8UDZ
John Hines