Yesterday I found time to sit at the bench and begin assembling the WKUSB keyer kit. It's not a formidable kit if you are not a beginner kit builder. It takes about 2-3 hours to put together. The parts come in separately sealed bags that more or less follow along with the assembly process. That is, you can open up one compartment at a time, place those parts, then move to the next compartment. So, you really don't need to spend time pre-sorting a single bag of parts.

This was my first chance to use my new soldering station, a Komec 936, which is essentially a knock-off of the higher quality Hakko stations. It costs about 70 bucks and comes with a full set of tips. Previously, I'd been using a simple 25W iron that is a bit too much for small parts. The Komec is temp-controlled and the smaller tips make the soldering process more of a sure thing.

As you can see, I like to place several components at once, usually around 10, before soldering and trimming a batch. I did have a little trouble at first finding the best temperature and the fine point tip I was using wasn't heating the lead and pad fast enough for me, so I switched it out for a small chisel tip.

The kit instructions are very straightforward and easy to follow, except for the very last assembly step, #18. That one deals with mounting the speed pot and I found them ambiguous at best. It tells you to mount the pot to the PCB, but also mentions cutting a couple of 7" wires, but doesn't say what they are for. What they should tell you is to cut one 7" wire, solder the stripped ends to the two pads, push them through the bottom side of the board, solder them, then cut that wire in the middle. Strip those ends and solder them to the pot. None of that is too difficult to figure out on your own, but it's a hiccup in otherwise very clear instructions.

Once assembled, I installed the USB driver on my shack PC and plugged in the board. Though it was slow (probably due to the 1200 baud WKUSB comm rate), XP finally found the board and successfully matched the driver. Trouble was that that was as far as I got. The only response I could get from the kit was an incessant short beep from the speaker every 2 to 3 seconds as long as it was plugged in. No adjustment of the pot, or use of the supplied test utility software has any effect on the keyer. 

There is very little troubleshooting information in the assembly manual. The only thing that seemed to apply was to check the input voltage of the PIC chip and that voltage was fine. I would really appreciate a table of test voltages, such as are always present in Elecraft manuals, to be able to narrow down the problem. I posted to the K1EL Yahoo group and got only a one-line reply from K1EL himself that perhaps the pot wasn't connected (of course it is). 

Update: Well, I thought the pot was connected, but it really wasn't. I sat down at the bench to do some voltage measurements and while checking that I'd wired the pot leads correctly one of them came off in my hand! Apparently, I'd been overly aggressive in trimming that lead. After re-soldering that lead the kit now has full functionality. Egg on my face, but thank goodness it was an easy fix. =%^)

1 comment:

  1. Good morning Casey, great to hear that all worked out in the end. Yes kits can be fun at times and frustrating at other times. I have run across the same situation as you did with not so clear instructions. That's when I head to the Internet and look for some assembly pic's. In most cases I find the pic's help me toward an answer.


Thanks very much for your comment! 73, Casey


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