HP 15CLE - how successful?

[Jim Horn]

As mentioned by others, aerospace and military still used lead/tin solder. While most vendors only supply ROHS parts anymore, they can be soldered with lead/tin as long as the temperature profile is controlled properly, a skill any decent assembly house has today. In my work at Wescam, Insitu, and United Technology Aerospace Systems (cloudcaptech.com), classic lead/tin eutectic solder has been the norm.

The tin whisker problem has been mostly tamed by careful selection of solder alloys, temperature profiles, proper conformal coatings and other tricks. But we're still not quite there yet. The greater brittleness of lead-free solder joints has also caused concerns in high vibration and temperature cycling cases such as ours. An example of failure of that last is many laptop computers have failed due to temperature cycling fracturing solder joints of their tiny QFN package power supply ICs (I've replaced same several times).

Fortunately, our calculators aren't subject to the high power and related stresses so should do pretty well. We'll see...