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After two years the original batteries in my 33S went dead. The screen just went blank, no low battery indicator. Fortunately no loss of programs after new batts put in.


Hi, Trent;

thank you for this information. Good, indeed!

Just to go deeper: IF you still have the old batteries, is there a way to measure the voltages, amps capacity so we can have more info? I have already experienced some strange behavior in calculators with one dead battery amongst the other ones. One of them that called my attention was an HP41 that simply turned itself off everytime I tried to print trhough the IR module. I tested a pack of fresh batteries and it worked fine. Then I measured the voltage in the `old` four batteries and they all measured about 1.45Vcc (regular Alkaline). Then I decided to measure their voltage while in the calculator, and when the calculator was turnned ON, there was a strange drop from 5.8Vcc to about 5.1Vcc, no BAT annunciator. When trying to print through the IR module, the voltage dropped to less than 3.8Vcc and the calculator simply turnned itself OFF without any warning. Then I decided to go ahead and measure each battery with different load values. One of them (they were a bit old) was unable to maintain the expected 1.3Vcc shown with the others with about 11 to 12mA, it simply dropped it to 0.2Vcc. I took it as a failty battery, because all of them were from the same pack.

Well, I guess you have already tossed the old batteries away, but I thought I should mention these facts. I have some CR232 with low voltage I keep for experimental purposes, I'll go ahead with some tests with my HP33S this weekend and let you know.


Luiz (Brazil)


Re the old batteries.

I don't have any fancy measuring equipment. However on my old Radio Shack battery tester both batteries put the needle in the middle of the red "Replace" range.


Just purchased a new HP-33s at the local college's book store day before yesterday. Had read about keyboard problems, so decided to run it through the diagnostic routine. Before I could finish the screen went blank. Dead batteries! Measured them at ~2.5 Volts with a digital meter. The new 2032s measured a little over 3.0 Volts.