HP-15c: Why so popular?

[ijabbott]

(11-07-2023 10:36 PM)tppytel Wrote:  

(11-04-2023 11:00 AM)lvt Wrote:  I bought a TI-83 for my sister when she entered secondary school (called "lycée" in France), the calculator barely lasted those three years until she graduated.

That's actually rather surprising to me. The early TI graphing calcs were solidly built in my experience, provided you took reasonable care with the screen. The TI-85 I bought for PreCalc in 1993 still works just fine, and we still had a ton of 81/82/83's kicking around our high school when I started teaching in 2000. The fat 84's seemed OK too, but the current 84CE's seem to have gotten significantly worse. I have multiple students with ~1yo 84CE's that just died or refuse to charge, which really sucks for a ~$120 device.

One Achilles' Heel is the battery connection - spring steel wire resting on PCB pads, which they wear through, creating a hole in the PCB pad, so the calculator won't turn on. Easy to fix by bending the contacts a bit so they contact a different part of the pad, or better yet, by flooding the pads with solder.