K2: 80m & 17m Weak RX, no TX

[John Frerichs]

Greetings,
   
  I just completed the Step 3 alignment on a K2.  On 80m and 17m I have weak RX and no TX power.  All other bands seem to work fine.
   
  The problem first became known when performing the Step 3, RX pre-alignment procedure.  I couldn't hear any appreciable difference in receive audio when tuning L3 and L4 from a signal sent from another transmitter (set to the same frequency as the K2), sitting right next to the K2.  I set L3 and L4 1.5 turns from top, as that's what worked well for the initial 40m alignment in Step 2.  I continued on with the alignment procedures for the other bands in sequence and they tuned up just fine (by ear, so no quantitative measurements are available).  When I got to 17m I had the same issue again.  The other bands (15m, 10m and 12m) all went well, however.
   
  I had the same problems with the TX alignment.  80m adjustments of L3 and L4 and 17m adjustments of C32 and C34 showed no power output on my external wattmeter (Bird 43).  On 20m~15m and 10m-12m I had no trouble getting full power output, however.
   
  On all bands except 80m and 17m the RX seems to work just fine.  With TX power, everything seems to work fine with the same exception.  What could I have missed?  I thought my understanding of the alignment procedure was thorough.  
   
  I'm not an RF engineer.  As such, I'm at a disadvantage.  I'm an experienced builder of many electronic devices, but this is my first transceiver.  
   
  Any constructive advice would be appreciated.
   
  Thanks,
   
  -- John
   
   
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[John Frerichs]

Duhh!  I'm so stupid!  I remember reading in the manual that some caps are marked with a zero and some aren't.  
   
  I still reversed Caps: 12/15 and 35/31.  Cap 12/15 values are "560".  Cap 35/31 are marked "560".  Guess what I did?  Yup.  I read value "560" and placed MARKING "560" in its place.  Argh!  What an idiot I am!
   
  Now I have to re-reverse them, so 80/17 will work right.  Yipes!  At least they're easy to get to!
   
  I'm kicking myself HARD for that idiotic blunder!
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[Brian Lloyd-6]

On May 27, 2008, at 9:28 PM, John Frerichs wrote:

> Duhh!  I'm so stupid!  I remember reading in the manual that some  
> caps are marked with a zero and some aren't.
>
>  I still reversed Caps: 12/15 and 35/31.  Cap 12/15 values are  
> "560".  Cap 35/31 are marked "560".  Guess what I did?  Yup.  I read  
> value "560" and placed MARKING "560" in its place.  Argh!  What an  
> idiot I am!
>
>  Now I have to re-reverse them, so 80/17 will work right.  Yipes!  
> At least they're easy to get to!
>
>  I'm kicking myself HARD for that idiotic blunder!

Don't feel bad about that. A couple of times the students pulled that  
one on me when we were assembling the K2. Fortunately I caught it and  
was able to rectify the problem before we went any further. This is  
why I would insist that two students work together with one stuffing  
the board and the other reading parts values. That way everything got  
looked at twice. It helped a lot but there were still errors.

Brian Lloyd
Granite Bay Montessori School          9330 Sierra College Bl
brian AT gbmontessori DOT com          Roseville, CA 95661
+1.916.367.2131 (voice)                +1.791.912.8170 (fax)

PGP key ID:          12095C52A32A1B6C
PGP key fingerprint: 3B1D BA11 4913 3254 B6E0  CC09 1209 5C52 A32A 1B6C




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