On battery leakage Message #9 Posted by Palmer O. Hanson, Jr. on 26 June 2007, 2:48 a.m., in response to message #1 by brianh
You wrote:
Quote:
... I just received a HP32E in great cosmetic condition. However, it suffered the dreaded 'battery pack leakage'.
What is interesting about all of the leakage problems is that there was a time back in 1972 when designers at both HP and TI understood that there was a potential problem with circuit damage from cell leakage and did something to prevent it.
You can see it in the HP product line in the Classic family where the assembled case provides a box around the battery pack. There was some of that in the Woodstock family. Any pretense of isolating the battery pack from the circuitry went out the window with the Spice family and the HP-41.
You can also see it in the TI product line in the Datamath machines. I recently purchased a TI-2500 (1972) -- the version with the six rechargeable batteries accessible through a trap door. I didn't have my Phillips head screwdriver with me but the device ran perfectly with the Adapter/Charger. I reasoned that there must not be any circuit damage from leakage so I bought it for a dollar. When I opened the trap door I found massive cell leakage. When I opened the calculator there was no circuit damage and I could see why. The case essentially formed a bathtub to enclose the cells and isolate any leakage from the circuitry. Any pretense of isolating the battery pack from the circuitry went out the window with the TI-30, TI-1XXX's, and the TI-5X's.
If the designers of the early machines at HP and at TI understood the need to isolate the circuity from cell leakage then why did the later designers abandon the concept? Did they begin to believe the claims of the cell manufacturers for their "sealed" cells? Did they decide that since the cell manufacturers were offering to repair devices damaged by cell leakage then the user would suffer no economic damage from cell leakage? Any ideas out there?
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