dolson@hppad.HP.COM (David Dolson) (11/26/90)
Help! I have an HP 28-S calculator which I purchased a couple of years ago. Lately, it has been resetting itself with no apparent warning. (e.g. I turn the calculator on and it beeps and the MEMORY CLEARED message appears. Sometimes my programs are still there despite the message.) This has happened about four times. I thought perhaps the batteries were getting low so I replaced them, but it has happened at least once since then. A friend of mine bought a 28S about the same time. His started doing the same thing a while ago until it stopped working entirely. I am wondering: is there is a known problem with the 28S ? Is my calculator doomed? Some people have suggested to me that this is a problem with different sized batteries, but this doesn't explain why my friend's 28S died completely, unless he had two unrelated problems. David Dolson dolson@hppadi.waterloo.hp.com
jpser@cup.portal.com (John Paul Serafin) (11/28/90)
My HP28C and HP28S have mysteriously cleared themselves a number of times since 1987. After a while I noticed that it was almost always in dry cool weather. I suspect that it is due to electrostatic discharge. It is particularly dangerous to touch a powered up HP28 after walking around or to walk around with a powered up HP28. I have had a single instance of this with an HP48 when i touched it during an archive operation. (ARGHH!) Always ground yourself before touching a powered up calculator if there is a possibility that you have built up a static charge. It might even be a good idea when it is off, but i haven't seen calculator get zapped when it is off. John Serafin jpser@cup.portal.com
wdr@wang.com (William Ricker) (12/11/90)
dolson@hppad.HP.COM (David Dolson) writes: >Lately, it has been resetting itself with no apparent warning. >(e.g. I turn the calculator on and it beeps and the MEMORY CLEARED >message appears. Sometimes my programs are still there despite the >message.) This has happened about four times. >I thought perhaps the batteries were getting low so I replaced them, but >it has happened at least once since then. I had a spate of these last summer, until a friend, a 28C owner, pointed out that he suspected battery life to be related to storage temperature. When I ceased parking my briefcase with 28S in outer pocket next to the Van Pool's Engine Housing (great heat source), I changed from Batteries per Month to Months per Battery quite acceptably. I'll easily believe the other poster's suggestion that electrostatic discharge can reset 'em too. I'm not going to test the hypothesis with the tesla coil at the office, tho. -- /bill ricker/ wdr@wang.com a/k/a wricker@northeastern.edu *** Warning: This account not authorized to express opinions ***