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Re: [Xylo-SDR] Xylo



----- Original Message ----- From: "ecellison" <ecellison@comcast.net>
To: "'Xylo-SDR Discussion'" <xylo-sdr@lists.ae5k.us>
Sent: Wednesday, December 14, 2005 11:56 AM
Subject: Re: [Xylo-SDR] Xylo


Folks

Every day I carry my Xylo around and pop it out when I have time. Yesterday
I got the Wolfson parts and DANG this is gonna be a problem! These things
are SMALL! How in the heck are we going to prototype these things? I grew up
in a world of leads and vacuum tubes! (smile). I searched around for
carriers and stuff and everything seems pretty expensive for these small
parts. We could produce a run of inexpensive carriers with caps and critical
lead length components on the carrier. We gotta do something to make it a
little easier to handle these itty bitty peppercorns! I know that Bill -
KD5TFD has done a lot of this and has some small prototype board sources.

I make my own PCBs, and often make my own adapters for small chips like that, instead of buying them. I use a stereo microscope for the very fine-pitch devices, but most of the time a bench magnifier is OK. 'Drag' soldering is the best technique for soldering chips like that, I have a special mini-hoof tip for my Metcal soldering station that holds a small amount of molten solder and is then wiped across a row of pins, after applying plenty of gel flux. Much the same can be done with a largish soldering iron tip, with a blob of solder on it, but a lot more cleaning up with desolder braid is required.

My Cyclone II chips should be delivered today, I see from the tracking info that they are on the van coming from their London depot.

Leon
--
Leon Heller, G1HSM
leon.heller@bulldoghome.com
http://www.geocities.com/leon_heller
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