I have recently acquired a 16C from someone who had not used it for a long while. It functioned perfectly when I installed new batteries but after a few days would not switch on. I tried all the tricks in the manual and within the archives of this forum. Shorting the battery produced "Pr Error" when subsequently switched on, but it would not then switch off! If I leave the batteries out for a few days it will then work....but not for long and we go around the loop again. Battery voltage is fine and it passes all self-tests when working. However, I have noticed that when entering numbers quickly (esp. repeated digits), the input is sometimes interrupted by the memory status displaying but I don't know if this is normal.
Any suggestions would be appreciated especially since this 16C is in near-perfect condition. Thanks in anticipation.