Finally replaced the leaky caps on my Mac Classic II

Nice job on the repair! On May 25, 2014, at 06:05 , Steven Hirsch <snhirsch at gmail.com> wrote: I've had to do a lot of surface mount rework at my job. Tuning up a GPS receiver front end involves a whole lot of check input return loss, change a couple of caps or inductors, repeat. Mostly 0402 size discretes, with some 0201 size thrown in for fun. If you're not familiar with those size numbers, then consider that an 0201 resistor is about the size of a grain of table salt. It took me a LOT of practice to be able to solder 0201s without damaging the board. After learning to do that, the 0402 components are quite easy to work with by comparison. Rather than the hot tweezers, I developed the habit of using a pair of regular irons, with one in each hand, under a stereo microscope. Hot tweezers are nice for larger components, but their tips tend to be a lot larger than pencil iron tips, and the alignment when closed isn't that great. When doing small surface mount rework, high-quality soldering irons with excellent tip quality, excellent thermal control, and enough heat capacity to very quickly heat up the joint without going over temperature are a must. In my experience it's a good sign if they say "Metcal" on the front, and run away if they say "Weller" on the front. I don't have experience with other brands; once I experienced how much better the Metcal MX-500 series irons work compared to the Wellers I always used before, I never went back. Also, liquid flux is your friend. It not only shields joints, but also modified surface tension and helps conduct heat into spots where it's hard to get good tip contact. I have a pair of Metcal irons at home now, along with an imported stereo microscope that I bought new on eBay. I have no trouble reworking anything with visible contacts. I can't do things like BGAs with inaccessible contacts at home yet, but one of these days I'll get a hot-air soldering system and/or put together a little reflow oven. When looking for a microscope for use in rework, a good ring-style illuminator that surrounds the objective lens is preferable. The fiber optic ones are the best, but are expensive. LED ones can be quite good. Fluorescent ones aren't as nice, but they're being displaced by the LED ones these days, anyway. You'll probably want to add a 0.5x objective lens to reduce the magnification and increase focal length. Just my two cents' worth regarding surface mount rework. It's really not so hard with the right equipment and some practice. -- Mark J. Blair, NF6X <nf6x at nf6x.net> http://www.nf6x.net/