HP30B retunrning to "default values"

[ElectroDuende]

Hi all,

I have had this HP30B unit for about six months; it has the suplied batteries (panasonic) and lately I've observed that, randomly, it reverts to default settings of language, decimal marker and... chain calculation AGGHHH! I don't store any program in it, so its not a major problem to re-configure it, but it is quite annoying when happens.

In test mode, first time you reach "tst Battery", displayed value is 2.400, but if you press enter, it will always show 2.9 / 2.900. Why is it like that?

I don't currently have any spare 2032 cell to test... but no battery warning has ever lit while I use it... is this the usual behavior when batteries are low?

Thanks!

[Katie Wasserman]

The low battery warning does not work in these machines and your 30b will resent when the battery voltage gets too low. This is unfortunately a very common occurrence with all the new HP ARM-based calculators. The power supply design is just horrible, they've put 2 CR2032 cells in parallel instead of using them blocking diodes so that one cell won't drain the other when it's exhausted or shorted.

I recommend that you buy a good supply of 2032 cells, they're under $0.25 on Amazon and elsewhere and change them often and carefully. "Carefully" because it's pretty easy to short the battery contacts when inserting a new cells and you'll reset the calculator.

[ElectroDuende]

(05-07-2015 01:34 PM)Katie Wasserman Wrote:  The low battery warning does not work in these machines and your 30b will resent when the battery voltage gets too low. This is unfortunately a very common occurrence with all the new HP ARM-based calculators. The power supply design is just horrible, they've put 2 CR2032 cells in parallel instead of using them blocking diodes so that one cell won't drain the other when it's exhausted or shorted,

I recommend that you buy a good supply of 2032 cells, they're under $0.25 on Amazon and elsewhere and change them often and carefully. "Carefully" because it's pretty easy to short the battery contacts when inserting a new cells and you'll reset the calculator.

Thank you Katie!

I knew (and suffered) about the battery indicator problems in the 15C LE, but didn't expect it will be the same in "non emulated models".

I didn't realize that they were wired in parallel... then an easy test can be done.

- Powered just by cell A: continuous resets, just trying to do self-tests or run little programs.
- Powered just by cell B: doesnt't seem to reset (just like when powered by the two of them... maybe some reset may happen "randomly").

Finally, I got a multimeter, Batt A: 2.3v under no load, Batt B: 2.8v under no load... clear now; I'll get a couple of them on my way home!

[Geoff Quickfall]

Also the battery hatch design is sadly lacking. A. Good knock or rap on the calc will temporarily disconnect the power supply causing the default. The battery then returns to position and the circuit is complete leaving you with a functional but 'defaulted' condition.

This happened to me with the 34s conversions when it was in my flight bag which gets tossed around at airport security. Fixed it by folding some paper to fit between the battery and the rear sliding case which adds more pressure holding the battery in place during these transient jolts.

Geoff

[ElectroDuende]

(05-07-2015 02:44 PM)Geoff Quickfall Wrote:  Also the battery hatch design is sadly lacking. A. Good knock or rap on the calc will temporarily disconnect the power supply causing the default. The battery then returns to position and the circuit is complete leaving you with a functional but 'defaulted' condition.

This happened to me with the 34s conversions when it was in my flight bag which gets tossed around at airport security. Fixed it by folding some paper to fit between the battery and the rear sliding case which adds more pressure holding the battery in place during these transient jolts.

Geoff

Good point, Although I don't think it is my case, as I've seen the reset several times in the last month, and I don't use to drop or knock it so often (ar least I try not to).