HP-41cx Won't Power Up

[Allen]

are there any gaps between the top and bottom halfs? You can try squeezing along all corners and see if the case halfs compress together and come apart causing a gap.

Some models will fail to power on if the top interal posts are broken (causing the battery terminals to lose contact with the pcb.) other models will fail to power on if the bottom posts ( behind the R/S key and x key ) fail to connect the motherboard to the flex connector with enough pressure.

With the calculator laying flat, it's possible to apply pressure on the keybord face on all four corners with 4 fingers on one hand, and with the other hand try the ON or ON+ <- + ENTER reset procedures.

Sadly this is quite common with the fragile plastic of these models to be get cracked internally in transit. I also received a HP41 this week with a broken post behind the R/S key and discovered it using the same method above.

(you are also right, that it's practically guaranteed to crack the case if opened, this vexes me greatly.)