41CV won't turn on after reassembly. Did I kill it?

[g8241CV]

Lots of more experienced people here (many great threads I researched before doing repairs on two 41's), but I would swap in known fresh batteries (1.5V) as your next step. Easy elimination of a variable for problem solving diagnostics, and you need them anyway to avoid the inevitable cell leaks from your weak existing cells. Then, before you try to close with your repaired post, suggest you try gentle cleaning of contacts (both sets, upper near batteries and lower for CPU PCB) with IPA, and use DeOxit. You're looking to eliminate a particulate contaminant on contacts that you may have missed in cleaning or dislodged during reassembly. While you're in there, suggest you use DeOxit on at least the bum key. Suggest you observe ESD precautions (e.g. use ESD strap).

Not sure what you mean by "shorting all the battery terminals" -- if this was really a short of all terminals, then no power to the calculator and that shorting may have reduced the cell voltage(s) below the operating threshold. You might post a close-up photo of the contacts since you had reason to be concerned.

Post back, don't give up too easily, there are lot's of other great threads on repairs to explore. It's a wonderful feeling when you bring a favorite calculator (CV for me) back to life.
HTH