Posts: 210
Threads: 45
Joined: Jan 1970
So far, every malfunctioning 41 I've seen has been either corroded contacts, or broken posts. Since your contacts are clean, I suspect it's a cracked/broken post. There is a screw under each foot, going into a post. If a post is cracked, there is poor contact between the electronics in the two halves of the calc. Depending upon how bad the posts are, they may be repairable. Check them out, and post your findings. I think many people here have experience repairing these.
Posts: 37
Threads: 5
Joined: Jan 1970
Before opening it you might want to go the the articles section and read article 149 ("Reseting an HP41").
Frank.
Posts: 28
Threads: 6
Joined: Feb 2006
On my experience,one situation also out of consideration,and it can make hp41 can not turn on,"the spring of battery holder", the "spring" was dead form "elastic deformation" it has not enough force to push up the battery to contact the battery terminal.Maybe you can try add some metal foil between spring and battery,may be solve your problem.
Wish it can help you.