I wrote the KXB3080 manual for Elecraft as well as the original assembly procedures for the KX1 itself. I'd like to make a couple of observations about the tools recommended in the KXB3080 option manual and the upgrade process.
Out of a desire for accuracy, while writing the procedures for a manual I use the tools listed in the manual, and only those tools. If I have trouble with them, I try to work out an easier build procedure or recommend different tools. I try to imagine those tools in the hands of the average builder. I get good input from the Field Testers as well. The procedures are not significantly different from any board work. The KX1 is just a little smaller and denser than most of the Elecraft kits, so you need to be a little more careful and take your time. In the case of the KXB3080, I did probably 2-1/2 KXB3080 installations/de-installations on poor ol' KX1 S/N 0004 while documenting the procedures. After all that "abuse" those are photos of poor ol' 0004's circuit boards in the KXB3080 manual. All of the soldering was done with a Hakko 936 soldering station and all of the desoldering was done with aid of a common spring-loaded pump desolderer as described in the recommended tools list. That was a spring-loaded desoldering pump, not a squeeze bulb or braid. I'm not saying that one might not do the job with a bulb or braid, but Wayne was quite clear and I agree that the safest route is to use a good spring-loaded desoldering pump. First you remove the part. Clipping leads, then clearing holes is always the safest way although, with care, many two-leaded parts can be removed intact. Obey the warnings about pulling on the lead before the solder is completely melted. You *can* pull the whole plated hole assembly out of the board. That can happen not just because you didn't get the solder fully melted. If, during the original assembly, you bent the leads over the edge of the solder pad to hold the part in place on the PCB, you may find yourself applying too much pressure on the pad tugging on the part trying to 'un-bend' the lead and pull it from the hole while keeping the solder molten. As long as heat is applied to the pad it is de-bonding itself from the circuit board. You do not need to save any parts that you remove from your KX1 while installing the KXB3080. Only one part in the KX1 is removed and re-installed. You move it from one side of the KX1 circuit board to the other. The KXB3080 kit includes a replacement for that part so you can clip the leads off the original. Once a part is off the board it's time to clear the hole. Now's when having both hands free is important if you're using a desoldering pump with your regular iron. It is easy to clamp the KX1 circuit board in many kinds of vices. Lacking a vise, a couple of small "bean bags" or a couple of books are great for propping up a board on edge when two free hands are needed. Don't forget to follow ESD precautions while handling the loose boards. It's also important to set up your work space so your arms are supported. It's very hard to work smoothly and accurately with your arms "floating" and all to easy to bump something with the iron. Use a 700F soldering temperature and wet the tip of the iron before touching it to the pad. Wetting the tip is important. Heat transfer is slow from a 'dry' soldering iron tip! Slow heat transfer increases the likelihood of finding a pcb solder pad stuck to the tip of your iron when you take the iron away. The more you 'cook' the pad, the more you loosen its bond to the PCB. Cock and position the pump over the pad on one side of the board, then touch the soldering iron to the other side of the board to melt the solder. Of course, choose the side of the board for your hot iron where you have the least chance of bumping into other parts and keep your eye on what you are doing with the iron. If the pump tip slips, it won't hurt anything. Not so with the hot iron. As soon as the solder melts, often no more than 1 second after touching the tip to the pad, press the pump trigger and "whack!" you have a clean-as-new hole in the solder pad. The time you have the iron on the pad is much shorter if you've clipped the component leads because there's no component there to soak up the heat. Still, a pad attached to the ground plane may take a little longer. Don't bother to remove the soldering iron tip before you press the pump trigger. Do them together or hit the trigger then remove the iron if that's easier. As you remove the iron, do *not* look at the pad. Watch where you're waving that hot iron tip until it's safely away from the circuit board <G>. Suppose you do pull your iron off of the pad and see the little "donut" of a pad stuck to it? If that's all that's there, you're rig is fine. It's a warning that you're using too much heat or, most likely, taking too much time. The plated-through section of the hole and the pad on the other side that connects to a circuit trace are still intact. There is no performance degradation whatsoever in losing the little donut on the opposite side providing it wasn't torn loose from the ground plane or a trace there. It will be barely visible after you install the new part. That solder pad represents damage, though. If it happens to you, take it as a serious warning that you're cooking the pads too much. The whole pad has been heated long enough to de-bond from the pcb itself. Be extra careful installing the new leads there. To me, the biggest concern about the soldering needed to install the KXB3080 is accidentally touching heat-sensitive parts that will melt in an instant if you bump them with a hot iron: pots and pot shafts, trimmer caps, relays and the like. I use a 2 mm spade tip on my iron. It's just about the biggest, fattest thing I'd ever want to use around the KX1 board! A power vacuum desolderer like the Hakko can be a wonderful investment and good addition to the bench. Like any tool, it requires the user understand its limitations and applications. It does greatly eliminate the need for two-handed desoldering. I'm aware that one can use a separate desoldering pump and iron on one side of the board. It works, but it usually takes more heat and more time. Because of that, it's a good way to debond pads. The Hakko 808 makes the job easier, for a price. Just be careful, very careful, what you touch with it. I've used similar tools. I've thought about getting one myself, but since we don't have it on the recommend tools list... Ron AC7AC _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
