Posts: 1,841
Threads: 54
Joined: Jul 2005
For long-time storage, I'd generally remove the batts to avoid leakage. There are many HP calcs dying the battery acid death, so there is no alternative if you don't look after the units on a regular basis. However it may be helpful for some hardware parts to get some electricity from time to time (say twice a year), but the hardware guys may have more info about this.
Actually I had a NIB HP-42S which had not been powered on for more than ten years, and which worked flawlessly when putting in new batts some time ago.
Every HP calc family has its own special deficencies, to my knowledge independent from the battery. The Pioneers suffer from shrinking foam connector pads, the HP-41 series mainly from battery acid damage. The Woodstocks weren't made to last: Fried ACT ICs are very common, due to connecting the AC adapter w/o working buffer battery. No coated pcb traces, prone to catch battery acid or other corrosion. Similar with the Spice series units. The Classics (incl. the Woodstock 67) sometimes have LED problems, and so on.
HTH
Ray
Posts: 883
Threads: 17
Joined: Feb 2006
IMO, all hp calculators should be stored with batteries removed as all batteries will leak when they fully discharge. The risk of leakage, by far, exceeds the very slight risk of capacitor failure due to lack of forming voltage.
Overall, the capacitor risk is incredible small and only applies to some of the models where there are high capacitance standard aluminum electrolyics. This would include later models of the 41, the 48 series and the models that followed them, time-wise.
Pioneers and Voyagers have a very low component counts so they are the most likely devices to survive long term storage. FWIW, Pioneers have no aluminum electrolytic caps, early Voyagers had one small value cap that was later was changed to tantalum - which do not dry out so they should be good for the long term.
Do not store in a bag to reduce the chance of condensation and provide stable temperature and humidity levels.
