Posts: 348
Threads: 74
Joined: Jun 2013
Electronic devices can have many things happen to them.
A stray gamma ray might hit the one bit of memory it uses as a cold start constant.
The battery power may have been interrupted unbeknownst to you and cleared ram.
If you have two 33S calculators, you may have picked up the clear one. (Being hopeful here).
But really, anything that relies upon battery power always runs the risk of memory clear. That's why offline storage or flash memory is so important.
Posts: 901
Threads: 113
Joined: Jun 2007
I lost memory in the first of my 33s machines by failing to see the battery annunciator which is easy to overlook because it is small and tucked up in the upper right corner of the display. I also failed to recognize that when the battery power is very low I would find that the machine may shut itself off but I could immediately start it back up and run for a short period of time. I think that this is a manifestation of the old characteristic where a battery recovers somewhat when it is off.
I also failed to see the annunciator when the battery power was low with my second machine. Fortunately, I also saw the self shut-off feature and remembered that it was time to replace the batteries.
Page A-2 of the manual states "... if the battery annunciator is on, and the display dims, you may lose data. ..." It may be that what I saw as a self shutoff was only a dimming of the display. but I returned the machines to operating condition for a short time by pressing ON.