[Elecraft] K3 Audio Upgrade Mod

[Monty Shultes]

I would argue for the piggyback approach.   Use a pair of "sprung" tweezers that can grasp the SMT resistor at a comfortable angle.  (I use a 1/8 inch chisel tip iron for almost all my work - gets in and out very quickly compared to a smaller tip.) There is plenty of space around the two resistors. Set the iron at 700 degrees, cooler than normal.   A drop of solder on the iron tacks one end of the piggyback resistor.  Then a proper quick, neat solder job on the other end, and lastly clean up the first end with a proper solder job.  The iron never spends more than a split second on the connection - being deliberate and speedy is important to avoid dislodging the original part.  Looks neat.
 
Monty K2DLJ
  The second part of the kit involves shunting two resistors with 51 ohm resistors,  and here also Elecraft gives two options: one is to solder 1/8w through-hole resistors onto the IO board, and the other is to solder two tiny SMT (surface mount ) resistors piggy-back onto existing SMT resistors. The kit comes with both kinds of resistors.  I elected to do the SMT version of the mod, and here I'd recommend that owners opt for the other method. I don't see any advantage to doing the  SMT version. It takes a very steady hand, a very small-tipped soldering iron, and very good eyesight to piggy-back the two SMT resistors into the circuit, and I just don't see the reason for the hassle. It would take five minutes to install the through-hole resistors, and the result looks quite clean and neat.  I'd recommend also that Elecraft delete the SMT option from the instructions. Took me about 30 mins to install the SMT resistors, probably about half that time to install the through-hole ones.

   

  73,

   

  Jim W8ZR 
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mailman.qth.net/pipermail/elecraft/attachments/20081204/69998def/attachment.htm