Re: [uCsimm] RTL Port, actually RTAI.

From: Tom Walsh (tom@mytoys.com)
Date: Sat Jan 08 2000 - 02:30:35 EST


Jim Richardson wrote:

> On 07-Jan-2000 Stu wrote:
> >> Phil mentioned that there were two other gentlemen trying to find
> >> time to do the Real Time stuff for the kernel: Bernhard Kuhn, and
> >> Florian Pflug. I just wanted to update you on my status, I received the
> >> proto PCBs this morning, destroyed (?) one in mounting the surface mount
> >> parts, and succeeded in building the other. I have not yet put power
> >> to the board to see if the BDM is 'alive', but expect to do that early
> >> next week (I have a Linux file server to deliver to a customer that used
> >> to run only Windoze!).
> >
> > Speaking of SMT parts, I got the MP3 evaluation board from IMBDev
> > (http://www.imbdev.com). Lots of surface-mount components. Can someone point
> > me to a good web or FTP site with hints on how to do this? I'm doing OK so
> > far, but I doubt I'm using the best soldering iron / solder combination.
> >
> > Failing that, can someone suggest a good wattage for a soldering iron and/or
> > a good type of solder to do SMT with? The kit was $160 and I don't want to
> > screw it up too quickly. :)
>
> If you don't mind spending about $100 more, get a good heat gun with the smt
> tips. Far easier than even a fine tip iron, although you do have to spring for
> the paste solder.
> Other than that, a 15-25 watt iron is fine, although you'll want a fine tip
> for a lot of the flat packs and such. Simply orient the chip right, tack down a
> corner, then the opposite corner, and then solder the remaining corners and
> start doing the sides. You can clean bridges easily with solder wick, but don't
> get any under the device, you'll play merry hob getting it out. For small
> componants like resistors and such, either use paste solder, which sort of
> sticks them down, or use a *tiny* dot of superglue to hold it down. After a
> while, you'll find that the glue isn't really neccessary, because if you flow
> the solder on one pad, the resistor is drawn into alignment by surface tension,
> although you have to be careful not to let it tombstone on you. It's not hard
> really, just takes patience, and a handful of used dental picks don't hurt :)
>
> Jim Richardson
> Anarchist, pagan and proud of it
> WWW.eskimo.com/~warlock
> Linux, because life's too short for a buggy OS.
>
> This message resent by the ucsimm@uclinux.com list server http://www.uClinux.com/

Yes, the heat gun would work ... this is essentially how Hakko does the surface
mount stuff. Hey! I remember, the guy that did the demo for the unit used a
chisel point on the soldering iron to touch the ends of the fine pitch devices, then
added some solder and let the leads wick the solder up! That would work if you are
real careful and don't add too much solder, use the ultra fine stuff. BTW, he did
the same thing, tacked two corners of the chip to the board before doing the rest of
them with the chisel.

TomW

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