K1 deaf after KNB1 installation

[Mike Morrow-3]

Byron wrote:

>My K1, #2799, build was going along swimmingly until I built
>and installed the KNB1 module...now my poor K1 is deaf

Hi Byron,

First, it would likely be best to mark a posting such as yours
with an "OT" for being clearly "off-topic" on this "All K3, Only K3,
All The Time" list!  :-)

Seriously, though, I'll assume that you had to install the RF board J1
connector as part of your KNB1 installation process.  In other words,
the J1 connector was not in place earlier when your K1 was working.

If that assumption is correct, then I'd look very very closely at the
K1's RF PCB soldered connections to the J1 connector.  Especially, check
for no solder bridges to ground (pins 5, 6, and 7) from signal pins
3, 4, or 8.  My money says that during J1 installation, either pin 4
or pin 8 got shorted to ground with a solder bridge.  Check pins 3, 4,
and 8 with an ohm-meter to ground (pin 5, 6, or 7).  If you get a very
low resistance, then that's your problem.  And since this is at the
RF board connector J1, the same symptoms would show regardless of
the KNB1 being in place.

Good luck.

Mike / KK5F
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[Bill K9YEQ]

K1 is not off topic, I am very interested and will build one soon.


73,

Bill
K9YEQ
K2 #35; KX1 #35; K3 #1744; mini mods
ATS-3B


-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Mike Morrow
Sent: Friday, December 25, 2009 4:14 PM
To: [hidden email]
Subject: [Elecraft] K1 deaf after KNB1 installation

Byron wrote:

>My K1, #2799, build was going along swimmingly until I built
>and installed the KNB1 module...now my poor K1 is deaf

Hi Byron,

First, it would likely be best to mark a posting such as yours
with an "OT" for being clearly "off-topic" on this "All K3, Only K3,
All The Time" list!  :-)

Seriously, though, I'll assume that you had to install the RF board J1
connector as part of your KNB1 installation process.  In other words,
the J1 connector was not in place earlier when your K1 was working.

If that assumption is correct, then I'd look very very closely at the
K1's RF PCB soldered connections to the J1 connector.  Especially, check
for no solder bridges to ground (pins 5, 6, and 7) from signal pins
3, 4, or 8.  My money says that during J1 installation, either pin 4
or pin 8 got shorted to ground with a solder bridge.  Check pins 3, 4,
and 8 with an ohm-meter to ground (pin 5, 6, or 7).  If you get a very
low resistance, then that's your problem.  And since this is at the
RF board connector J1, the same symptoms would show regardless of
the KNB1 being in place.

Good luck.

Mike / KK5F
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[Byron N6NUL]

On Dec 25, 2009, at 2:14 PM, Mike Morrow wrote:

> Seriously, though, I'll assume that you had to install the RF board J1
> connector as part of your KNB1 installation process.  In other words,
> the J1 connector was not in place earlier when your K1 was working.

This occurred to me on the way to a Christmas Eve party and I kept it in mind but took a some time off from the problem to enjoy Christmas.

After carefully inspecting all the parts for bridges today, cleaning up a few flux spots, etc., and taking some high resolution photos with a macro lens and my D200 (ala QST) I thought I would have to go the RF probe route.  I re-installed the KNB1 and KAT1 to wait for tomorrow.

The football was so bad tonight, however, I decided to take another look and then build the RF probe in the manual in preparation.  As I took the K1 apart again, I was placing the KAT1 back in it's bag (I like to keep the boards and all their parts in the original marked bags when not in the K1 itself), I noticed the jumper that I removed from the KFL1-4 when installing the KAT1 and immediately slumped in my chair.

Sure enough, that was it.  I had removed the KAT1 and moved the RF-DET jumper to K1, but I had not replaced the J2 jumper between pins 2 and 10!  This jumper connects the antenna to the input of the low pass filters on the KFL1-4.  When listening for a signal, it really helps to have some RF from the antenna going in to the receiver!

Once installed, the N-GEN and X2 signals (even the 1uV signal) are loud and clear.  Good thing, too, because I did something wrong with the probe and my DMM is not reading!

Anyway, tomorrow I can thoroughly re-calibrate my K1; both RX and TX.

Thanks for the ideas,

Byron KI6NUL
p.s.  I am using Signal Scope on my iPod touch to monitor the waveforms.  It seems to do a pretty good job.
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[Mike Morrow-3]

Byron wrote:

>I had removed the KAT1 and moved the RF-DET jumper to K1, but
>I had not replaced the J2 jumper between pins 2 and 10!

Well, I'm glad it has worked out OK for you.  That's the trouble
with remote troubleshooting...others can't see what alterations
have been made that have nothing to do with the complaint.

I think that you'll really enjoy the K1.  The K1 doesn't get much
press anymore, but I still consider my nine-year-old K1 (sn 175)
to be the best QRP rig for its size that's available.  Were I in
the market for a good portable QRP rig today, the K1 would still
be the only one that would be satisfactory to my needs, just as
it was almost a decade ago.  (My K1 was ordered in June 2000, and
delivered in November 2000.)

Mike / KK5F
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