K2 no rx audio

[Kevin Hulina]

I am going through the tests of my newly built K2 and I'm getting no
receive audio.  I am able to get side tone, and if I give the radio a
signal it shows up on the S meter, but I don't get any receive audio.  I
have done the PLL reference oscillator, vco, bfo and agc tests.  All
those seemed ok per the troubleshooting.  I have tried other bands and
am not able to get the white (atmospheric) noise on any band.
Any thoughts?

Thanks
Kevin
W9KH

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[Don Wilhelm-4]

Kevin,

Did you install the jumper wires at the R18 or R19 locations on the
Control Board?
If you instead installed Control Board J1 and J2 in anticipation of
adding the KAF2 or KDSP2, you need to add a wire jumper between J1 pin 1
and J2 pin 1 and another between J1 pin 2 and J2 pin 2 before you can
hear any audio from the RF board.

If that is not the problem, take a look at the connector soldering on
the Control Board and the Front Panel Board.  Are all pins soldered -
especially pin 1 on the Front Panel.

Examine those boards carefully for solder bridges.
Follow the audio path on the schematic for the Control Board starting on
the right side of the schematic at the PD1 and PD2 points, through the
MUTE transistors Q6 and Q7, then onto the Front Panel AF1, AF2 and AF3
signal lines.  You may have to remove the Front Panel metalwork to gain
access to those signal paths as they move to the front panel board.
Touching a screwdriver to the AF1, AF2 and AF3 lines should result in a
bit of hum pickup.

73,
Don W3FPR

On 4/26/2015 6:51 AM, Kevin Hulina wrote:
> I am going through the tests of my newly built K2 and I'm getting no
> receive audio.  I am able to get side tone, and if I give the radio a
> signal it shows up on the S meter, but I don't get any receive audio.  
> I have done the PLL reference oscillator, vco, bfo and agc tests.  All
> those seemed ok per the troubleshooting.  I have tried other bands and
> am not able to get the white (atmospheric) noise on any band.
> Any thoughts?

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[Kevin Hulina]

SCOOOOOOOOORRRRRRRE!!!!!!
Thanks Don :)  In the end, I reflowed the control and front panel
boards.  I wasn't able to see any bad solder joints (I am using a
magnifier), but apparently there was one somewhere....  Powered it up
and got noise :) :) :)

Kevin
W9KH


On 4/26/2015 7:39 AM, Don Wilhelm wrote:

> Kevin,
>
> Did you install the jumper wires at the R18 or R19 locations on the
> Control Board?
> If you instead installed Control Board J1 and J2 in anticipation of
> adding the KAF2 or KDSP2, you need to add a wire jumper between J1 pin
> 1 and J2 pin 1 and another between J1 pin 2 and J2 pin 2 before you
> can hear any audio from the RF board.
>
> If that is not the problem, take a look at the connector soldering on
> the Control Board and the Front Panel Board.  Are all pins soldered -
> especially pin 1 on the Front Panel.
>
> Examine those boards carefully for solder bridges.
> Follow the audio path on the schematic for the Control Board starting
> on the right side of the schematic at the PD1 and PD2 points, through
> the MUTE transistors Q6 and Q7, then onto the Front Panel AF1, AF2 and
> AF3 signal lines.  You may have to remove the Front Panel metalwork to
> gain access to those signal paths as they move to the front panel board.
> Touching a screwdriver to the AF1, AF2 and AF3 lines should result in
> a bit of hum pickup.
>
> 73,
> Don W3FPR
>
> On 4/26/2015 6:51 AM, Kevin Hulina wrote:
>> I am going through the tests of my newly built K2 and I'm getting no
>> receive audio.  I am able to get side tone, and if I give the radio a
>> signal it shows up on the S meter, but I don't get any receive
>> audio.  I have done the PLL reference oscillator, vco, bfo and agc
>> tests.  All those seemed ok per the troubleshooting.  I have tried
>> other bands and am not able to get the white (atmospheric) noise on
>> any band.
>> Any thoughts?
>
>

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