There are no pictures to post today, because there's not that much to see ... a modest number of parts distributed all across the bottom side of the RF board. It has turned out that installing parts on the bottom of the board has been the most difficult part of the project so far.
I found Elecraft's standard instruction to stuff some large number of components on bottom side of the board and then go and solder them all really didn't work for me. It almost seemed like I needed to customize in some fashion the installation of each component ... a bit of exaggeration, but I certainly did need to assess how I was going to install each component.
There were two main issues to deal with:
- Crowding on the top side of the board can make it necessary to solder a component on the bottom side of the board.
- You have to insure that no component is higher than the 2-D fasteners on the bottom of the board, so as to insure that nothing touches the bottom panel of the case when the K2 is assembled.
The instructions for installing components on the bottom board are prefaced with a brief paragraph that says basically "you may have to solder to the bottom of the board." In actuality, I soldered all the components in the last batch on page 59 on the bottom of the board, and I probably would have been better off soldering most of the components from the first batch on the bottom as well.
Soldering on the bottom was only really problematic for the monolithic capacitors, since they sit flush with the PC board and there is no lead exposed to solder to. For a lot of these, I ended up soldering them to the top of the board, even under some alarmingly crowded conditions. It turned out the solution was to put a 90° bend in the lead a very short distance away from the capacitor's body, trim the leads off, and then stuff them into their pads. The bend would expose the lead and then it was easy to solder. Depending on the size and location of the capacitor, it could then be bent upright or just left alone.
Thanks to Gary at Elecraft for helping me out with a couple of questions about bottom-side construction this week. In particular, he pointed out that C133's leads can be formed such that it sits lower than the nearby 2-D fastener and there is therefore no need to bend its body (which was a good thing, because there's really no place to bend it to!).
I took a day off from stuffing/soldering earlier in the week (I really needed a break!), and went ahead and wound L16 to L24 (on page 70). These will all now be waiting for me when I get to that stage of construction.
At the top of page 60 ...