Re: HP 15C Message #3 Posted by OJM on 9 Jan 2003, 11:33 a.m., in response to message #2 by Vieira, Luiz C. (Brazil)
Before opening up the HP15C for surgery, there is one other possibility for this HP15C behavior. A fellow engineer in my office tried to resuscitate his HP15C with new batteries after a long hibernation, but after installing a new set of cells, he couldn't get it to start up, even after trying the various reset keystrokes and shorting the battery terminals. As a last resort, we switched batteries with those from my own HP15C, and his calculator started right up. The only difference we could find was that the new cells he had purchased were silver-oxide cells (SR44) while the cells I had in my calculator were alkaline cells (LR44). There is a slight difference in voltage, with the siver oxide cells having an open-circuit voltage of 1.55 -1.60 volts, while the alkaline cells have the typical 1.50 volts. Apparently his calculator did not like the slightly higher total voltage. My calculator, strangely, didn't seem to mind. We checked to make sure it wasn't a problem with dirty contacts, etc. so this was a little strange. You may wish to check which kind of cell you are using in the calculator, just in case.
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