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

[rprosperi]

It might be improper contact of the battery terminals. Though this is not a common problem in Pioneer machines, it does tend to happen in those that have had some kind of battery leakage in the past.

The simplest and best (and as a bonus, cheap) to clean contacts, for any calculator or other kind of device, is with a glass brush. Here is one from Amazon:

https://www.amazon.com/gp/product/B0019V18D2

[robjordan]

Thanks Bob. Interestingly, I momentarily removed the batteries, and the memory was preserved, as it's supposed to be. The manual says that memory will be preserved for around one minute. So I'm inclined to think it may be an internal electrical fault, or a software issue.

[rprosperi]

In your (Pioneer) case, it probably is an internal issue, but I'd still try it; as I said, it's easy and cheap and might solve the problem - no harm trying.

I've seen cases where corroded contacts, which apparently repeatedly making/breaking intermittent contact can cause behavioral problems somehow "worse" than simple battery removal. I don't know the actual damage mechanism which leads to erratic behavior, perhaps the pulsing on/off damages the system in some way which leads to reset/mem lost, etc.

I have a 41 that had experienced battery leakage in the past that behaved exactly this way - by this, I mean would sometimes spontaneously MEM LOST, but other times was OK and would even retain memory during a battery change. I finally solved the problem by thoroughly cleaning the spring tips in the battery holder with the glass brush. Fortunately in this 41, the gold contacts on the battery/port block were undamaged. After cleaning the contacts, this 41 has been stable.

All that said, Pioneers are drastically different internally than a 41, so a successful fix for one means nothing for the other, but at least it's something to try.

Let us know how this turns out and what solution (hopefully) works in the end.

Good luck!