Texas Instruments TI-86 graphing calculator problem - need help, fellow users...

[metroplex]

I have a TI-86 that I bought in 1997 and have run into a problem. It is currently sucking my NiMH rechargeable AAA batteries DRY after only 1-2 days of being shut off. The voltage on the batteries will read near 0V only after a few days of simply sitting inside the calculator.

I am guessing that it is somehow either turned on in a way that the user doesn't see, or its internals are somehow damaged or fried or I need to do a full reset. I have tried pulling the little watch battery to reset it, but it still sucks batteries like there's no tommorrow.

Any ideas?

 

[imported_Phil]

Could you measure the voltage, turn it "off", wait an hour or so and measure the voltage again?

 

[metroplex]

I can do that. Are you trying to determine whether the batteries are at fault? I have popped in freshly charged NiMH AAA's (750mAh - 800 mAh) and they'd do the same thing. My TI-89 that I bought in 2002 is very nice on the batteries. I can get months of life out of my NiMH AAA batteries.

 

[imported_Phil]

Well, I'm not a TI-86 owner. In fact, my calculator is calc.exe
However, I'm trying to get a feel of how fast the batteries are discharging when the unit's "off".

 

[metroplex]

16:41 EST, 1.2-1.26V DC

 

[cHeeZeFacTory]

how old are the batteries?

 

[metroplex]

Less than a year old.

 

[metroplex]

Update: Well, 1 of the 4 batteries just pretty much died (0.034V DC) while the other 3 are at 1.25V DC.
I put my ammeter through the battery circuit to see the current draw. It draws 8.3 mA OFF, and 11-15 mA while running.

Using my calculations, a fresh set of 800mAh AAAs will last a max of 4 days on standby, so something is wrong.

What should I do? It's totally out of TI's warranty and I'd still like to keep using the TI-86.

 

[Crono]

Do a fullreset, under the memory settings. Is this just with NiMH batteries or alkaline as well?

 

[metroplex]

It's only on the NiMH. My TI-89 draws 5.3 mA on standby. I just did the full reset again.