17 Oct
2012
17 Oct
'12
11:24 a.m.
On Oct 17, 2012, at 12:18 PM, Tothwolf wrote:
On Wed, 17 Oct 2012, David Riley wrote:
I suppose. I've had terrible luck with bridging, but I never
really kept at it long enough to get much good at soldering
fine-pitch parts. My wife got me a pretty decent iron as a
birthday present recently, though (I picked a good one!), so
I may be doing a bit more in the not-too-distant future (more
so if my QBUS board ever gets off the ground, because I don't
really feel like paying for assembly).
On Oct 17, 2012, at 10:10 AM, Liam Proven wrote:
> On 17 October 2012 13:05, David Riley <fraveydank at gmail.com> wrote:
>> To my recollection, the 386SX only came in surface- mount packages. The N8VEM
folks (including the S-100 group) have done a pretty good job of making sure all their
boards can be assembled with only through-hole parts, which makes it a lot easier for
novice solderers with cheap irons.
Despite how they look, QFPs are among some of the easiest surface mount parts to fit. A
25W pencil iron with a small tip (~2mm) and some liquid RMA flux will do the job. I've
used irons with tips as large as 4mm for this task when in a bind. Granted, I've been
soldering for decades, but still...SMT isn't /that/ hard... It was also extremely common to see AMD 386DX QFP
chips fitted onto a PGA carrier board that could be plugged into a standard i386DX socket.
I own a bunch of these (and motherboards for them) which I plan to use for a future
multi-processor project. [That is, IF I can ever get my hands on enough 40MHz 387DX math
co-processors -- one guy on eBay has had them for more than 10 years but his per unit
price makes my project cost prohibitive since I need at least a dozen of them.]
I had never seen them, but then I realized that I didn't start
building machines until the 486 era. SMT-on-a-carrier is
certainly a common paradigm; after all, it's basically what
flip-chip PGAs are on a different scale.
- Dave