23 Jan
2012
23 Jan
'12
12:54 a.m.
On Jan 22, 2012, at 4:02 PM, Dave McGuire wrote:
I've used them for some QFP parts that we needed to drop on a breadboard when I was an
undergraduate. I found that the trenches were even more helpful for preventing bridges
than they were for registration, but since I was an undergraduate with no knowledge of
signal integrity, the resulting nest of wires to put it onto a solderless breadboard
caused considerable ringing problems (I only point this out to make Tony's finger
start wagging :-).
All in all, probably not bad products, but kind of expensive. For sticking small pitch
parts onto breadboards (solderless or perf), I tend to prefer the ones from Bellin
(http://www.beldynsys.com/), especially their P513 kit
(http://www.beldynsys.com/p513.htm). They're still not super-cheap, but $45 for about
150 pieces (300 patterns, double-sided) isn't a terrible deal. They stick onto your
breadboard with a minimum of wasted space and look kind of pretty (and even have fairly
intuitive pinouts for parts like SOT-23s).
- Dave
On 01/22/2012 03:56 PM, Chuck Guzis wrote:
I always seem to get a lot of bridges unless I do it with paste and a toaster oven.
I'm sure it's something I'm doing wrong instead of some intrinsic problem, but
it's enough to make me think twice when it's a problem.
Also, I have a pretty crappy 30W Weller whose finest tip is about as sharp as a moderately
used pencil, which makes cleanup rather difficult even with desoldering braid. I'm
sure with better equipment (say, a proper Metcal and sharper tweezers, plus maybe at least
a magnifying glass and a hands-free grip) I could do a better job. I have a hard time
with 0402s right now only because they keep sticking to the damn iron.
Many hobbyists seem to be deathly afraid of
soldering SMT,
particularly fine-pitch (0.5 mm) QFPs.
I've never understood it. I'm now deep into the through-hole pass on an
assembly job I'm doing, and I'm hating every second of it, while the SMT parts
were a breeze. The world is full of backward people, it seems. The fear of SMT is a
knee-jerk reaction with no foundation in reality. At some point,
someone offered adapter cards with, for the want of a
better term, employed a "trench" for each lead, so that
misregistration was almost impossible. I don't know if they're still
made or even how difficult it would be to fabricate such a thing on a
circuit board--but it might bear investigation for future kits.
Yes, Schmartboard makes those. They sent me a sample a few weeks ago; I haven't
tried it yet.