HP-41CV power-on weirdness

[rprosperi]

That was quick, but unfortunately confirms the problems are probably deeper than simple broken posts, however there is a chance it is only dirty connections, as seeing instructions like CLX followed by NULL means the CPU (and display drivers, etc.) is working, at least to some extent.

You're going to have to open the unit and minimally clean the zebra or ribbon connectors; it's likely it's not that simple but without opening it, you'll never get to the bottom of the problem.

Are you handy with electronics? If not, I'd say find someone who has experience working on a 41, as even the act of opening the unit can lead to post damage and you could end up worse off. If you want to do the work, get a copy of Jose's excellent book "HP41 Repair: A beginner's guide to repairing your HP41 calculator", available from Amazon, and also check out TheCalculatorStore, which carries a wide selection of quality repair parts for almost any 41 repair issue.