hp 45


Hello all classic enthusiasts,

I just got lucky yesterday and inherited an hp 45 from a co-worker. It was her father's, and she just found it in her desk drawer. Of course, it has a corroded rechargable battery pack, and some corrosion salts inside the compartment.

I read the writeups on batteries and on classics disassembly here in the MoHPC--and what I am wondering is two things:

Has anyone found a non-rechargeble battery that can be used instead?

After getting a new battery (either rebuilding the battery pack, or getting a new battery), is it safe to merely clean the battery compartment, and give it a try? I guess I am concerned about opening up the case uneccessarily. I know from my experience with my first and only 41cv, that the screw posts can be quite fragile and damage to them can be terminal (I still have not gotten that machine back to life).

In the case of my 41, I found some small corrosion deposits inside---but that machine had worse battery corrosion than this 45.

Any thoughts?




Yes, you can just clean up the battery compartment and give it a try. Howecer, there might be some corrosion growing inside the machine. Leaving it there could be bad news in the long run.

The classic machines do not have screw post problems like the HP41. Occasionally their screw "posts" will split, but it does not affect the workings of the machine.


Thanks, David!

So then, I guess your suggestion is to go ahead and carefully open her up!?




I'm sort of 50/50 on opening it up. If you can clean the battery area up well and the machine operates properly (all keys work well, switches are OK, etc) then you might not want to open it. If the machine has significant signs of use, I would probably open it. Usually battery corrosion gasses like to affect the top row of keys and the row with ENTER first.



you can use alkaline batteries in the HP45.
The problem with opening the calculator is, that two of the screws are under the back lable. I did not find a way to peal it off without damaging it.


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