Monday, May 27, 2013

The K2 is starting to take more shape

The K2 is starting to take shape
I have now completed the first section of the RF board build. This is a very exciting stage as the front panel, control board and RF board are fitted together and power is applied and the K2 for the first time comes to life!! Well that is the plan as long as all the checkout with the RF board goes as planned. My resistance checks on the RF board went well. I did have to send off an email to Elecraft about one of the readings but all was well. It turned out to be a "builder (me) can't read the meter correctly" so all checked out with the
removing the tape
resistance checks. It was time to get out some side panels and bottom panels and prep them for assembly. There is some tape to be removed from the panels and a razor knife will help out with this. On my first K2 the tape was not that firmly applied but since then this tape is very hard to remove....BUT....under the tape is a very important bar metal finish. There are some 2D fasteners to put on and it's important to pay attention and put them on the correct way. No big deal if you mess this up it just means you will have to stop the assemble and redo the 2D fastener as things will not line up. The tilt bail is also going on at this point and I have always had trouble with this baby. Even following the Elecraft instructions this stand has always been a challenge to get in under the feet that secure it in place. As I mentioned earlier in the build it's very important to make sure the "J" and "P" connectors are all square on the board. During this part of
2D on bottom installed correct
the assembly you for the first time are going to mate "J" and "P" connectors to each other. One thing I wanted to bring to your attention, during the front panel build you were instructed to place two rubber sticky type feet to the two top corners of the board. Well I had forgotten about these feet I put on....until.....this assembly. The control board  and RF board mated together very well. When I added the front panel board (which included the front plate and the knobs and so on.) to the control/RF board things seemed wrong. The front panel had some resistance to it not wanting to mate with the 2D fasteners at the top! Before I realized what it was I had taken the three boards apart over 4 times looking for the trouble.....then I saw it! It was the two rubber feet on the front panel board they were lining up with the 2D fasteners on the front side panels. This was how it was supposed to work the rubber protected the board from the 2D fastener. The resistance I was feeling was normal and it would be great if Elecraft included this in the assembly instructions as it would had saved me some time.When I take the unit apart I will post about this as then I can add some pictures to make it more clear what I mean. It's now time to power up the unit and see how is works! Then I move onto my first alignment of the radio.
Proper mating of "P" and "J" connectors.

Wednesday, May 15, 2013

Front panel almost complete


Front panel almost complete.
Installing encoder wires
With the front panel almost complete it's adding the VFO encoder that completes the front panel build. Before the VFO encoder can be added you are asked to install 4 component leads to the board that eventually will be the VFO encoders connection to the front panel board. The best way I found to put these leads on is using my alligator clip vise. I place the front panel board in my Pana vise and the leads are held in place with the alligator clip vise.The picture to the right is not the best quality but gives you an idea of the concept. Other methods I have tried with my previous K2 build did not work as well as this method.
The VFO encoder requires some assembly onto a circuit board as well as some components to install as well.  Elecraft introduced a new encoder in March 2012, the old encoder did not have a circuit board. Also the encoder's shaft is a bit larger and a new style VFO knob is included. Old K2 VFO knobs will not fit over this shaft.  Regarding the PC board make sure you trim the leads on the bottom of the PC board. If the leads are not trimmed there is a possibility the leads will come in contact with the control board. The control board and front panel board are in time going to be attached to each other and the tolerances between the two boards at certain point  are very close.  I did find a 4 pin SIP (J connector as Elecraft calls them) connector in the bag of VFO parts. I emailed Elecraft as I thought this could be used in place of running the 4 component leads. They had no idea how the 4 pin "J" connector made it's way into the parts bag. I was advised to use the 4 component leads as the assembly manual states.  When the time comes to fit the front panel PC board  to the front cover  you will also add the nut that secures the VFO encoder to the front cover plate.  Just a word of caution here is to make sure you DO NOT over tighten the encoder nut. If over tightened the VFO readout (once you get to that part of the build) will be very erratic. I find the nut if torqued to just  beyond finger tight is good.

Monday, May 13, 2013

Onto the RF board...let the adventure begin!

The RF board 
Relays are in
With the front control board and front panel board done and in the books it's now time to move onto the RF board. This is where toroids are wound, crystals are installed along with "can" grounds as well as a host of adventures in soldering and chekout testing! Oh and I am working on another page for the blog having to do with the front panel. I have the control board page....and soon a front panel board page will be released on the blog. I have installed the MANY relays and a word of caution here is to check and double check to make sure once all the relays are installed that you have soldered ALL the terminals!! It is very very easy to miss one and when it comes time to do a checkout involving the relays things will not work out as planned if you have left an unsoldered terminal on one or more of the relays. I am speaking from experience as with my first K2 build I did have some issued that came back to unsoldered relay terminals. Now it's time to add just a few resistors, caps and sip connectors (or J connectors according to Elecraft)....along with a few other this and that's. Not to keep harping on the cautions....but....caution is to be taken when mounting all "J" connectors. Upright and square with the board is the way to go. As mentioned before in the blog take your time with these connectors. The nice part about this section of the build is the RF board does not have to be complete before you get a chance to power things up. You soon will have the joy of seeing the Elecraft K2 come to life with an LED readout and everything!!
Resistors anyone!

Sunday, May 5, 2013

A way to mount control knobs right the first time!

Starting to look like a K2
The front panel is now complete I mounted the VFO without any problems...but...On page 32 you are asked to secure the front plate and PC board (via a standoff) with a 4-40x 3/16 flat head screw.  According to the front plate you will see this screw should be beveled. I used the 4-40 82 degree flat head screw here.  Once the front plate and front panel are together  the radio starts to take some shape. It's now time to add the control knobs and I am a fuss pot and want the knobs to be the same height off the front panel plate. I have found a sure way of doing this and it adds a nice finish to the radio when all the knobs are placed the same distance off the front plate. Here is how I do it and it's simple, cheap and works every time!