[Elecraft] Another UK K2 - 3314

[Robert Cochrane]

Guys

K2 3314 is now finished in its basic form after six months, with about 
another six months to go before the accessory boards are all complete.

Many thanks to you all at Elecraft for your support (particularly Gary) and 
to Don Brown for his help with T5.

There are probably a hundred or so K2s now completed in the UK.  So nothing 
in this message is really new, but I hope that coming from the UK it will 
encourage more Gs and Ms to get out their soldering irons and feel the same 
sense of achievement at each stage of completion.

A good and accessible overall review of the K2 by a UK builder is that by 
Neill Taylor G4HLX, Practical Wireless Dec 2002 and on the Elecraft web site.

A recurring question is what construction ability, and what tools, are needed?

It is over forty years since I built my Heathkit all valve hi-fi and over 
ten years since I built my last complex kit (a marvellous Hart 
Lindsley-Hood hi-fi amplifier, now manufactured by Williams-Hart).  So I 
warmed up by building some tools first - in particular an OHR watt meter 
and dummy antenna (www.OHR.com).

By the time the K2 arrived, my basic soldering skills had returned, but I 
was still overawed by the number of tiny components and the complexity of 
the RF board.

The next step was to buy a temperature controlled iron (an SL-30 with 
digital readout from Van Draper with a set of different sized tips, which 
has proved very reliable), a binocular headband mounted magnifying visor 
and an adjustable lamp with a circular florescent tube.

In addition I bought a Vermason anti static kit from Farnell (good value 
for a big mat and wrist set, but a larger mat than I really need - other 
firms such as Maplin have smaller, cheaper sets now and the portable 
computer technician sets are big enough for a K2 workbench) and a new set 
of needle pliers, flush side cutters and locking tweezers.  Did not use a 
panavise for the boards, but my Dremel portable D-vise (with soft and hard 
jaws) was very helpful, particularly for soldering leads to socket pins etc.

The visor was essential for close vision and provided full eye protection 
as well.  Mine came from Kanga UK which is regrettably closed at 
present.  Horizon Magnifiers advertise the OptiVisor in the UK, but I have 
no experience of it.  A simple watchmaker's eyeglass also helps with 
checking for poor joints and bridges, particularly if like me you have long 
sight and are the senior side of fifty.

The shadowless lamp was also a great help.  I actually bought one with a 
magnifier in its centre, but I don't use it, preferring the binocular 
visor.  Highly recommend you try out the various options if you can to 
check what works for you, particularly if you already wear glasses.

Once I had the right tools, construction was much easier.  It is a big 
project, but is definitely within the ability of anyone who has practiced 
soldering (see the excellent notes on the Elecraft site) and completed a 
couple of simpler projects.  However (as everyone has said) removing 
components from the beautiful boards with their through plated holes is not 
straightforward and it is vital to check and double check components before 
soldering the second pin, particularly ICs and tall multi-pin connectors.

Made two mistakes - bent an IC pin under and did not notice until I had a 
several pins soldered, and damaged a capacitor changing the lead pitch from 
2mm to 4mm as needed by the board spacing.  And had another slightly tricky 
component removal task when I added the thermistor frequency stabilising 
board, which replaced a multi-pin resistor network.

If you have to remove an IC with more than one soldered pin, it is 
essential that you sacrifice the chip, get another one from RS or Maplin 
(or Viewcom Electronics in Plaistow, who sell the rarer ICs such as the 
SA602AN individually at very reasonable prices) or ask Gary to send one, 
carefully extract the pins and carefully clean out the holes and the board 
with de-soldering copper braid.  I had no success with a sucker and cannot 
justify the best solution, a de-soldering iron such as the Hakko.

The only problems which were beyond my control were the fit of the front 
panel (corrected by trimming the connecting pins - watch out for the 
occasional builder's alert) and the VCO calibration.  Don Brown reassured 
me that I was not alone on the latter and suggested that I change the first 
winding of T5 to 17 turns, which did the trick.  (Perhaps there is a note 
in the manual by now - the bold headline on page 52 of my manual put me off 
experimenting...)

The real message is to take your time.  The K2 plus accessories really does 
take those of us with multiple lives a winter to complete - allowing for 
the usual business and domestic interruptions.  Treat it as a medium term 
project, taking six months to a year.

Do the parts check and sort out all the components into little (non-static) 
bags with labels on them.  That way, if you travel on business and for 
pleasure as I do, you can pack up and start again quickly.

Read the manual carefully and follow it step by step.  If you are returning 
to the hobby, remember that after a hard day in the office, old eyes cannot 
concentrate for more than about 40 minutes at a time and three sessions in 
an evening will be enough.  Set the chair slightly on the low side to ease 
your neck and save that well earned beer until afterwards...

And wearing an apron with loops sewn on the bottom hooked onto the 
underside of the bench (as my SMD microwave friends do) may sound a bit far 
fetched, but it is a lot easier than vacuuming underneath amongst the dusty 
power supplies and the roll of RG58 with a cloth over the pipe end to find 
the miniature capacitors after you drop them as I did.

Finally, don't feel embarrassed about asking for help.  The Elecraft guys 
at the works and on the reflector are a real community.

And now on to the accessory boards and another twenty toroids!

  Wayne and Eric - thank you.

Rob
M0RAC
VR2ARC


Robert A Cochrane
7 Lawn Terrace
Blackheath
London SE3 9LJ   UK

Tel (44) 020 8297 1978
Mob (44) 07764 197 701