Tuesday, August 31, 2010

Page 25

Today I did page 25 of the Front Panel assembly instructions ... not many parts but a lot of pins (three ICs and the bargraph LED). The picture also shows Q1 and Q2 and the bottom side of the 40 pin socket for U1, which I had stuffed the other day.

The only noteworthy item today was the amount of force that it took to get J1 (the microphone jack), at the lower left corner of the board, properly seated.

In case you're wondering, assembly instructions start on page 14 and run through page 83.

Monday, August 30, 2010

Back at it ...

I was away for a week at Pinewoods, and am still recovering from a week's worth of not enough sleep. However, I managed to turn on the soldering iron this evening and stuffed a few components, including the 40 pin socket for U1 on the bottom side of the board.

Hope to make more progress tomorrow.

Thursday, August 19, 2010

Started the Front Panel

I kicked off assembly of the front panel board today, mounting all 16 push button switches and a small number of fixed resistors (including two on the bottom of the board). Using the little "switch spacing tool" which Elecraft provides, it was very easy to mount the switches at a fixed and uniform space about the PC board.

Wednesday, August 18, 2010

Control board done

I've completed construction of the control board, including scanning the bottom side of the board for shorts, cold solder joints, etc., as well as doing all the short testing recommended in the chart on the last page of the control board chapter.

The last two components to be mounted on the board are the two capacitors which comprise the keying shaping add-on to the board. It took quite a while to get C46 in particular situated on the board, so I thought it would be interesting to document how this came out:

The actual component for C46 was quite a bit larger than depicted in Figure 4-11, so the insulation bits needed to be a little shorter, and the leads needed to bent more squared off then in the figure.

Finally, I'm happy to report that I had installed RP2 correctly. Apparently, I'm the first person to ever write to Elecraft support after finding Figure 4-11 confusing WRT RP2 placement. Many thanks to Gary at Elecraft for helping me out with this today!

Tuesday, August 17, 2010

Control board almost finished

As you can see, construction of the control board is just about completed. All top-side components have been installed, with today's stuffing of all the integrated circuits. What remains to be installed are 2 capacitors on the bottom of the board, which are a circuit essentially added to the board design to provide improved keying shaping; but I ran out of steam to do that task this evening.

The other thing that held me up today was the pictorial of the underside of the board where these two capacitors are to be installed. If you have a look at the top right corner of the board, you can see the resistor network RP2 installed in its rectangular outline on the board. Just to the left is a round solder pad with the ambiguous marking "1". The pictorial of the underside of the board implies that that is where RP2's pin 1 should go. I think the marking on top of the board is most likely correct and the pictorial probably represents some older rev. of the board, but I wrote to Elecraft for clarification.

Sunday, August 15, 2010

Plugged in

Despite all the dire warnings in the manual, installing the off-board connecting plugs was really pretty straightforward. The only one which was slightly tricky was P1, since it would be possible to install it such that pins were not parallel to the board. However, once I got it seated correctly, I used an alligator clip to hold it in place and then soldered it in. The two-row plugs seated pretty much seated themselves.

P5 and P6 came with warnings about soldering each pin less than 3 seconds each, so as not to melt the plastic shells. I just made sure the soldering tip was really clean before I did the soldering and it really wasn't a problem. Maybe Elecraft can think about supplying plugs not so susceptible to heat damage.

Looks like one more stuffing session should finish up this board ... I'll post a picture when it's completed.

Saturday, August 14, 2010

Control Board Transistor, etc., Day

I had a good working session today, during which I installed all the transistors on the control board, as well some voltage regulators, crystals, and a socket for the PIC CPU for this board. Starting with this post, you can click on these small pictures to get the big view.

Here is the control board so far. Today's assembly was quite straightforward, except for one possible mishap. After soldering Q5, I discovered it had slipped prior to soldering such that it was way above the board. After some attempts at reheating (and being very pleased with how the new solder pump worked!!), I finally clipped it out, cleaned the holes, and did it again. So, I hope Q5 survived the reheating.
The crystal cases need to be grounded. The procedure described in the manual for doing so was very straightforward and worked well. I found it handy to tape the little piece of grounding wire down to hold it in place for soldering.

The other thing I did today was rig up a grounding clamp on a local cold water pipe, ran a piece of antenna wire down from it, and clipped my wrist grounding strap to the wire. Hopefully, this is an adequate grounding scheme. In any case, I kept the wrist strip on while handling all the transistors, etc., today.

Thursday, August 12, 2010

Control board capacitors are installed

I completed stuffing all the top side capacitors.

You can see in the large photo that there is no C44; the board markings are apparently from a previous rev. of the kit. Also, the two apparently "leftover" capacitors are actually C45 and C46 which will be mounted on the bottom of the board as part of a key shaping circuit which has been added to the design.

Tuesday, August 10, 2010

Lots of solder ... not many components

Once again, I got a late start today. I installed all the resistor networks and a few other discrete components. The mounted component count didn't go up much today, but there were quite a few connections to be made. Rather than bending pins out to hold the resistor networks in place, I used short pieces of tape to keep them steady and flush to the board during soldering.

I have promised myself to stop working if I'm tired, so I didn't move on to the next chunk of component stuffing, despite today's low component count.

No pictures today. My next session will plant a forest of capacitors on the control board. When that's done, I'll probably post another picture.

Monday, August 9, 2010

And I'm Off ...

I finally managed to sit down at my bench last night to actually start construction. The K2 consists of three major board-level modules, the Control Board, the Front Panel Board, and the RF Board. The control board is the first module to be assembled and I thought I would document the beginning of construction with a few photos.

Here are all the parts for the control board sorted out into an egg carton and a clear container that I picked up in someone's trash one day and just had to bring home . The second clear container (picked up on the same trash picking run) contains most of the parts from the K2's "Miscellaneous" bag (Click here for a bigger view of this).

And I couldn't resist (heh-heh) documenting my stuffing the first resistor of the construction project.