[Elecraft] K3 Audio Low Pass Filter

[Geoffrey Mackenzie-Kennedy]

Mike,

The method that I use to clear holes in pcbs that are filled with solder is 
similar to pushing a heated wire through the hole, but I use a sewing needle 
instead because solder will not stick to a needle. As you did with with the 
wire, keep heating the needle with an iron while pushing it gently down 
through the hole, until some of the needle passes through the hole.You will 
have to get rid of any "blobs" of solder that fall out during the process of 
course.

Working in close quarters is not difficult with this method

I keep a number of sewing needles of different diameters/ lengths at hand 
for this purpose which I "borrowed" temporarily from my XYL many years ago, 
and to some of them I have added a small diameter grip at the thread end, so 
that I can hold the needle by hand when I do not want to use needle nose 
pliars.

It is a good idea to keep Vias open and not filled with solder, otherwise 
they may not function properly in some cases, but be careful not to damage a 
Via when removing solder.

73,
Geoff
GM4ESD


Mike Scott wrote on Friday, July 03, 2009 at 9:04 PM:

>I just completed an installation of the K3 audio low pass filter board, the
> one Lyle put out to individuals who wanted to try it. I was busy until now
> as the boards came out some time ago.
>
> It took a lot longer than expected because all the K3 DSP board holes were
> full of solder. The instructions seemed to indicate that four of the holes
> should have been clear, i.e., just stick the leads through. The 
> instructions
> seemed to be missing a section though as they never suggested soldering 
> four
> of the wires. I thought maybe a page was missing but the step numbers 
> didn't
> seem to indicate missing steps. Anyway, solder wick and solder suckers
> didn't work. The holes are very small and it is tight quarters where a
> miscue of the soldering iron could cause damage. I finally had to heat the
> wire I wanted to put in the holes (resistor leads) and heat my way through
> the soldered holes.
>
> For future reference, what would be the right way to do this?
>
> I would like to consider making more audio modifications, the one changing
> headphone audio coupling capacitors to larger values for example. I looked
> at those capacitors and I wondered how I was going to get them out. The
> solder leads on one side seemed to be down at the bottom of a narrow 
> canyon
> caused by interfering components.
>
> Mike Scott - AE6WA
> Tarzana, CA (DM04 / near LA)
> NAQCC 3535
> K3-100 #508 / KX1  #1311