27S MEMORY LOST - what's the cause?

[robjordan]

I have a 27S, which is my favourite daily calculator because I love the algebraic solver. Unfortunately, I get a MEMORY LOST error from time to time, at which point I have to re-enter all my equations. I've become quite organised about it. I record all equations, using a DIY IR serial device plugged into a PC, similar to the Martin Hepperle design. All the same it's a pain, and I wonder if there is anything I can do to prevent this from happening.

Most times it seems to occur at power-on, and once every few weeks. Today I experienced a freeze while actually using the calculator, then MEMORY LOST when I tried to turn off. Batteries are reasonably fresh, so I don't think it's battery failure, though I wouldn't rule out a poor connection between batteries and terminals.

Do you think it's more likely to be a physical cause such as loose connection, or aging electronics such as an internal failing capacitor, or are there software issues which could cause this? Any remedies? I was wondering whether I could squeeze a small axial capacitor inside the battery compartment, just in case it's momentary battery disconnection that causes the failure.

Thanks for your thoughts
Rob