[hpsdr] solder Janus

[Christopher T. Day]

Here are some notes I made while assembling the RefLock II board. I
believe there are no parts on Janus that are any smaller. The RefLock II
did come with the CPLD already soldered on, but having done a few lower
pin count SMD ICs I suspect the "tack one pin, tack opposite pin,
slobber solder across the pins, remove excess with solder wick" approach
will work for them.


	Chris - AE6VK

Assembly notes

Tool suggestions:

A magnifing lamp or equivalent. The parts and silk-screen markings are
quite small.

A pair of tweezers with sharp points and a soft squeeze. Check local
cosmetic boutiques. If the tweezers are too stiff, there will be a lot
of energy stored in them while you are trying to manipulate tiny parts;
a slip will send the part flying into oblivion.

Some kind of "third-hand" to firmly hold the circuit board while you are
soldering parts. I used a Panavise with circuit board holder head.

One, preferably two, sharp tipped 15W soldering irons. I got mine at
RadioShack.

In a few cases, 15W will not supply enough heat so something bigger will
be needed. I used a small 100W soldering gun; I would be careful going
to higher power, and 50W is probably sufficient.

A non-clean flux pen is handy. I found a Kester #951 pen at my local
RadioShack.

Keep the tweezers non-magnitized and the tips clean of adhesive from the
parts pages. It can be frustrating to place the part perfectly and then
not be able to let go of it.

Keep the soldering iron tips sharp, and clean with a damp sponge, cloth
or paper towel.

Use anti-static precausions. Ground yourself just before touching
components, or use a grounding wrist strap. The CPLD at least is static
sensitive.

For soldering techniques, I basically followed the procedures described
at http://www.tapr.org/~n7hpr/dsp-10. I particularly like the twin
soldering iron technique for handling SMD resistors and capacitors. One
modification I made to the process was to put down some flux _before_
tinning the pad and placing the components. The parts in this project
are smaller than those on the DSP-10, and these tend to stict to the
flux pen.

It should take no more than a second or two with the irons to melt the
solder for each of the small parts. Don't linger as the small pads will
delaminate if too much heat is applied.



-----Original Message-----
From: khmlist [mailto:khmlist at broadpark.no] 
Sent: Saturday, June 03, 2006 11:40 AM
To: hpsdr at hpsdr.org
Subject: [hpsdr] solder Janus

***** High Performance Software Defined Radio Discussion List *****

Reading thru the wiki for HPSDR, I was wondering what tools one must 
have to solder Janus and the rest? I assume that "a small soldering 
iron" is not enought, as some part is realy small. Would there be any 
chance to order those board with preasembly of the "dif parts"?
rgds
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