peraino@gmu90x.gmu.edu (peraino) (11/22/89)
In the very near future, I will be posting an article giving
in-depth information on power consumption statistics for the HP-28s.
In it, you will find many interesting things. Here is a preview:
A while back someone posted an undocumented storage mode for the
calculator; if you press on-enter-backspace at the same time, the
calculator will beep and shut off. Even the internal clock stops!
When the calculator is normally off (NOT in storage mode) it draws
13.5 uAMPS. In "storage" mode, it draws 106.2 uAMPS!! This is 7.8 times
the current drain! So what is "storage" mode really doing?
Stay tuned...
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Bob Peraino UUCP : uunet!pyrdc!gmu90x!peraino
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-----------------------------------------------------------------------------prestonb@hpcvra.CV.HP.COM (Preston Brown) (12/05/89)
> A while back someone posted an undocumented storage mode for the >calculator; if you press on-enter-backspace at the same time, the >calculator will beep and shut off. Even the internal clock stops! >When the calculator is normally off (NOT in storage mode) it draws >13.5 uAMPS. In "storage" mode, it draws 106.2 uAMPS!! This is 7.8 times >the current drain! So what is "storage" mode really doing? Your right, it does draw higher current; its basically a bug in the hardware. The storage mode or "Coma" mode was designed for factory checking of the leakage currents of the ICs (a very good measure of IC reliability) and as a mode the calculators could be shipped in to increase the shelf life of the batteries. The only problem is that a pin on one of the ICs is left in a high current state. It shouldn't cause any problems with your calculator only you can't use it as a low current state. Preston Brown