KX1: Deaf after KXB3080 installed

[Mike F.]

I thought I was nearing completion of my KX1, but I seem to have a problem now.

Upon completion of the basic KX1, all tests were completed as expected.  Current & resistance tests were right on and I was able to peak the 20m & 40m trimmers as directed in the manual.  I'm using an XG2 signal generator as a signal source, set at 1uV output.

I then installed the power modification kit (2 resistors) and began work on the KXB3080.  That was an intense, eye-fatiguing evening, particularly with the LPF1 board.  However, it all went together exactly as described in the manual.  BTW, I'm using Mychael's torroids throughout.  After getting everything assembled & installed, I repeated the current & resistance checks as directed and they were all exactly right.  However, when I went to realign the receiver trimmers, I no longer hear any signal regardless of their setting.  I hear something akin to background noise (as I did prior to the KXB3080), so it isn't an audio issue.

I've double checked solder joints, checked to be sure the KX1 is in "nor" (CW) mode, and is on the correct frequency for the XG2's output (and I tried moving frequency up and down a ways in case the KX1 freq display is off a bit).

Where would I go from here?  Thanks for any help you can provide!  I'm hoping to take this on vacation with me this weekend :).

--
73,
Mike, KC0KBC
Yaesu FT-857D, FT-8800R, VX-7RB
Elecraft KX1 #1819 (in work), XG2
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[Don Wilhelm-3]

Mike,

Check all the changes that you made during the KXB3080 installation.
Especially check T2 and the LPF to be certain the toroids are installed
exactly like the photos in the manual.  It is important to have flush
trimmed the leads on the LPF board relay so they do not contact (and
scrape) the windings on L1 and L2.

Did you make the PC trace cut as specified on the bottom of the KX1 board?

You know the receiver worked before the KXB3080, so most of the receiver
does work - the KXB3080 changes the components in the front end of the
receiver, so you will find your problem there.

Try using the 50 uV output from the XG1 to see if you can find the
signal - the 1 uV may be too low until the receiver front end has been
initially tuned.

73,
Don W3FPR

Mike wrote:

> I thought I was nearing completion of my KX1, but I seem to have a problem now.
>
> Upon completion of the basic KX1, all tests were completed as expected.  Current & resistance tests were right on and I was able to peak the 20m & 40m trimmers as directed in the manual.  I'm using an XG2 signal generator as a signal source, set at 1uV output.
>
> I then installed the power modification kit (2 resistors) and began work on the KXB3080.  That was an intense, eye-fatiguing evening, particularly with the LPF1 board.  However, it all went together exactly as described in the manual.  BTW, I'm using Mychael's torroids throughout.  After getting everything assembled & installed, I repeated the current & resistance checks as directed and they were all exactly right.  However, when I went to realign the receiver trimmers, I no longer hear any signal regardless of their setting.  I hear something akin to background noise (as I did prior to the KXB3080), so it isn't an audio issue.
>
> I've double checked solder joints, checked to be sure the KX1 is in "nor" (CW) mode, and is on the correct frequency for the XG2's output (and I tried moving frequency up and down a ways in case the KX1 freq display is off a bit).
>
> Where would I go from here?  Thanks for any help you can provide!  I'm hoping to take this on vacation with me this weekend :).
>
> --
> 73,
> Mike, KC0KBC
> Yaesu FT-857D, FT-8800R, VX-7RB
> Elecraft KX1 #1819 (in work), XG2

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