Monday, September 20, 2010

Grounding the crystals

Today was "install crystals on the RF board" day, including the scary instructions for double-grounding X7 to X11.

First, though, here's a picture of the current state of RF board construction. You can see X7 to X11 at the extreme right hand side of the picture.

After struggling to get the first ground wire on X7, I then went and checked the K2 forums to see what hints I could find. I wish I had looked there first! I used the following tips which various folks contributed to the forum, and it was pretty straightforward after that:

  • This was probably the most helpful hint (and non-intuitive, considering the dire warnings about overheating the crystals!!), namely to use an 800° tip, instead of the 700° tip I've been using.
  • I used some really fine grit sandpaper on the side of the crystal can (can't say it necessarily helped, but probably didn't hurt and may have helped).
  • I then applied a little solder to the side of the can.
  • I also had decided on my own to apply solder to each of the leads prior to installation.
  • Someone had a great hint about dropping the leads into the holes from the bottom of the board and soldering them to the board first. This was really the enabler for handling the inside leads (between the crystals and RP4).
  • I trimmed the leads in place to the correct length and used the "press it down with the flat end of a screwdriver" hint.
Anyway, there are all in, all grounded, and hopefully not overheated!

Next ... on to winding toroids!