[Elecraft] K3 Audio Upgrade Mod

[David Lankshear]

Bill, W4ZV wrote:


Make one!  http://www.al7fs.us/AL7FS5ATSprint2.html  (2nd pix down)

...and   http://www.qsl.net/n5ib/surface_mount/

73,  Bill

Thanks, Bill.  I heartily endorse this little device.  I built mine from a wire coathanger, a couple of fishing weights, a toothpick and a two-screw coupling cut from a choc-block connector.

After a wee bit of practice, I was happy to work with 0805-size components and larger.  I built a 23cm preamp for another amateur that used 0805's and it worked just fine.  I do use an Optivisor as an aid to my ageing and very short sighted eyeballs, but can honestly say I'm at ease with 0805s.  Solder paste, I believe, makes life easier due to its stickiness, but as it has a limited shelf-life and is rather expensive I have only heard stories of its being used successfully.

For SMT chip removal I've used a length of fine enamelled wire in a loop under pins.  As each pin is heated, the loop is pulled and as solder melts, the chip leg is lifted clear of the PCB.  I've never damaged a PCB doing this.  I believe Chipquik low melting point solder is very good (Wood's metal?) to aid removal by flooding the pins with the special solder, which remains liquid for a considerable time.  I believe there are special clean-up techniques using their flux to get PCB pads clean.  For soldering fine-pinned components, I just flood the pins with solder and then use solder wick to remove surplus.  Works fine for me.  For two or three connection SMTs I use two soldering irons and then a bit of solder-wick, pre-coated with additional flux from a flux pen, to clean up the pads.

I know this is tempting fate, but I can't remember the last trace I lifted, it's so long ago.  Just be careful and patient and allow yourself time to THINK about the approach you are using for each and every circumstance.  As amateurs, we are unlikely to be under serious time constraints when soldering, so don't rush into anything.

73  DaveL  G3TJP
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