Hi all, new Curta type 2 owner here.

I have a bit of a problem with my Curta, if I input a number in the register and say turn the add crank, the result will sometimes not be the number entered. The problem seems to be random, I've tried inputting the numbers always moving up, or always moving down but no difference.

I'm thinking it needs cleaned, and or lubed? I was hoping that it just sat for years before I got it and some use would clear it up but that doesn't seem to be the case.

Here's an example of my inputs and results from turning the add crank:


input: ---> result after add crank:
222 ---> 222

clear

314 ---> 324

clear

440 ---> 440
clear
7440 (just add 7) ---> 3440

clear

000 ---> 000
170 130

clear

170 (after moving) ---> 170


Any thoughts? Thanks!

Must not be a common issue?

I've looked at the basic tear down of the unit and I think I'm up to the task.

I'm going to open it up and have a look, maybe the problem will be obvious.

Wish me luck!

Yes, good luck



Sometimes a careful done cleaning helps...
Your described error seems not replicable - so this could be in fact some dirt...

Thanks Murff,

Last night I took the two bottom screws off and slid the base off.

I was hoping to see a smoking gun but everything was reasonably clean.

I took some cotton patches and cut them into small pieces and cleaned the input sliders using tweezers to hold the cotton, the cotton soiled fairly quickly so I was clean something off. I used a gun solvent to wet the cotton, seemed to work well

I then cleaned the slider rail inboard of each input slider and the crispness of the detents really improved. I then cleaned everything I could see and reach.

I debated on using any oil, in the end I lightly oiled a cotton swab and just rubbed each input slider shaft barely. This really helped the detent crispness.

I've ran several calculations without an error so time will tell if I fixed it 100% but so far so good!

I'm happy to report my input error was fixed with a simple cleaning. If you have the same problem I recommend pulling the bottom screws and giving the sliders a cleaning, and everything you can see. Tedious but not difficult.

cool !




[ . . . recently I cleaned this Curta ]




happy Spring