25 Oct
2010
25 Oct
'10
7:28 p.m.
On 10/25/2010 01:54 PM, Philip Pemberton wrote:
Hi guys,
First and foremost: Congratulations!
- Some of the component pads are rather small
(notably the inductors
and Schottky diodes in the power supply). This makes it hard to heat
both the pad and the component pin at the same time, and thus makes the
parts a bit of a pig to solder. I worked around this with a hot-air gun,
preheater and solder paste... later boards will have bigger pads.
- The power supply chip is a QFN with pads under the chip. The only
way to solder it down is to use a hot-air gun... unfortunately TI don't
make this chip in a more accessible package, and the only viable
alternative would have nearly doubled the size of the power supply.
[[ assuming I didn't mis-read the statement, and I'm teaching your
grandmother to suck eggs... ;-) ]]
The only thing I might be able to contribute to this discussion (as I'm
barely figuring out basic PAL/GAL logic in WinCUPL right now) is:
Instead of a heat gun, have you tried a mini electric oven or what we
call in the US a "toaster oven?"
http://store.curiousinventor.com/guides/Surface_Mount_Soldering/Solder_Past…
http://www.sparkfun.com/commerce/tutorial_info.php?tutorials_id=59
http://www.seattlerobotics.org/encoder/200006/oven_art.htm
I pointed a co-worker towards these articles about a year ago when he
mentioned he had a JetDirect board that quit working and he thought it
was a "chip with no pins" that could be at fault; he followed the
directions, repaired the board and it's been working fine to this day,
he's repaired a few other items (including an XBox360) in this manner as
well.
I will say that I have not tried it (yet) as I'm just getting further
into my hobbies after about 5 years; I'm down to one job instead of 3...
Hope this helps!
Roger "Merch" Merchberger