HP41CV never forgets?

[Bruce Larrabee]

Hi everyone. Okay I have at least one HP41CV that never forgets. I can remove the batteries and come back months later, put the batteries back in and turn the calculator on and the memory is all good, data intact. I also had HP41CV motherboards sitting in a box for YEARS, some of these still had data intact when assembled in to a calculator and fired up.

Has anyone else seen this? Anyone know anything about it?

[Steve Simpkin]

I have seen this ocasionally with my HP-41C. I always take the battery pack out when I am done using it. Months later I put the battery pack in and turn it on. Usually it comes up with a memory lost but sometimes it has everything in it from when I used it last.

[Craig Thomas]

One of my favorite calculators. Interested in selling one?

I live near Seattle, WA.

Craig

[HP67]

(05-04-2014 07:41 PM)Bruce Larrabee Wrote:  Has anyone else seen this? Anyone know anything about it?

Oh, you probably had that special mod Snowden was talking about

In all seriousness it sounds like typical HP over-engineering. They probably specced a nice filter cap for the power supply and it is enough to power the RAM when not in use.

[Bruce Larrabee]

Actually that is more or less what I have been thinking too.

[Marcel Samek]

(05-05-2014 06:15 AM)HP67 Wrote:  In all seriousness it sounds like typical HP over-engineering. They probably specced a nice filter cap for the power supply and it is enough to power the RAM when not in use.

How difficult would it be to mod an HP-67 to hold its memory for a long time?

[HP67]

(05-06-2014 05:16 AM)Marcel Samek Wrote:  

(05-05-2014 06:15 AM)HP67 Wrote:  In all seriousness it sounds like typical HP over-engineering. They probably specced a nice filter cap for the power supply and it is enough to power the RAM when not in use.

How difficult would it be to mod an HP-67 to hold its memory for a long time?

I don't know but I'm sure somebody here will.

[Visu]

Just repaired yesterday a colleague's 41CV that was supposed to be dead.

First try was to put the batteries on the right order - not successful.

Rubbed the pads, unscrewed the case, and how unsurprisingly noticed that one of the notches (one of these embracing the bacon connector) was broken. Superglued it, reassembled the whole thing and bingo, was alive again.

What suprised me is that after all these years (more than 10 according to the colleague) "USER" was turned on, european number format and f CAT 1 showed a bunch of programs that must have been written years ago.

Yes, it's not a "C" for nothing !