On 03/31/2017 02:00 PM, Paul Koning wrote: >> On Mar 31, 2017, at 1:51 PM, allison via cctech <cctech@classiccmp.org> >> wrote: >> >> On 03/31/2017 06:32 AM, David Griffith via cctalk wrote: >>>> I'm down to the last few P112 boards for sale and am pondering >>>> another run of them because demand is steady. One of the biggest >>>> challenges for the last run was getting the QFP-packaged 100-pin >>>> chips[1] in a state such that the pick-and-place robot wouldn't throw >>>> a fit about slight differences in lead position. The stuffing house >>>> insisted that I send them new chips. Pulls, though they looked >>>> perfectly okay to me, were not acceptable. Does anyone here know >>>> anything about pick-and-place robots using pulled 100-pin QFPs, >>>> particularly a stuffing house that can work with such chips and not >>>> screw up? >>>> >>>> [1] The now-obsolete super-io chips >>>> >>>> >> Is this something that an experienced hand can manually do? > Yes, definitely. 100 lead PQFP is perfectly doable if the lead pitch is not > insanely small. It takes a good fine tip soldering iron (mine is a Weller > with a PTS tip), fine solder (preferably real, i.e., 63/37 non-PC solder). > Liquid flux is a big help, as is a magnifier and bright light or modest > magnification microscope. > > If you have to do a couple of dozen boards this gets very tedious, but for > 5-ish it isn't a big deal. > > paul > So happens I'm fully equipped on all counts. Including the PTS tip. However my preference for years has been the PTA7K (WTCP60) which is 1/4" wide! Gets a few pins done at a time... ;)
I've not gone over to the Rohs side, most of the solders are not fun to work with though a few have very active fluxes and solder aluminium well. So its Kester 44 in 10 and 20 mil (inch mil) diameters. I've done more than a few AD537 and similar Blackfin CPUs with their 288 BGA package that's a challenge to pull and replace. Allison