Hi all,

Earlier I needed to do something with my graphing calculator. It only
gets used very rarely so I wasn't surprised when it didn't switch on. I
immediately suspected the batteries, but they were fine. All the same, I
slipped in a brand new set. Still nothing. In the battery compartment
they have an arrangement of 4xAAA cells in series to give a 6V supply.
However, on checking the voltage from 'head to toe' as it were (from the
first '-' to the last '+') I got a reading of minus 3V instead of the
plus 6V I'd expected. Checked all the connections and the probes in the
right sockets and whatnot: all fine.
I'm sure I've had this issue before with a different battery appliance in
the dim and distant past but can't recall what the cause was. It's like
it's too far in the back of my mind to resurrect any more. Can anyone
assist, please?

On Tue, 11 Apr 2017 23:37:29 +0100, Gareth Magennis wrote:

You are not checking from "head to toe".

You might think you are, but you are not.

You were right! However there's still something not right about the
continuity of the battery caddy. Unfortunately I can't go any further
tonight partially due to the stupid modern prods you get with the absurd
amount of shrouding which is making it impossible for me to 'get right in
there' as I would like (and these prods don't have the removable
shrouds). So it'll have to wait til tomorrow when I can get some more
suitable ones.

On 4/11/2017 4:24 PM, Cursitor Doom wrote:
On Tue, 11 Apr 2017 23:37:29 +0100, Gareth Magennis wrote:

You are not checking from "head to toe".

You might think you are, but you are not.

You were right! However there's still something not right about the
continuity of the battery caddy. Unfortunately I can't go any further
tonight partially due to the stupid modern prods you get with the absurd
amount of shrouding which is making it impossible for me to 'get right in
there' as I would like (and these prods don't have the removable
shrouds). So it'll have to wait til tomorrow when I can get some more
suitable ones.

Take the socket from a PC power supply IDE disk power connector
without the plastic part.
Solder a short piece of piano wire to one of the connector sockets.
Fits nicely over typical DVM probes and can fit into small places
for probing battery sockets.

I have a few vintage battery power radios that have multiple voltage take-offs (taps) at various points within the battery case. One (uses six (6) D-cells) has the 9V end-to-end, a 3V-from-two tap, and a 1.5V tap for the intermittent dial-light. Another using four has taps at 6, 3 and 1.5. It would not surprise me if your calculator had similar conditions.

Clean the contacts. Check for broken or cracked connections. Check each individual cell for the correct voltage (and polarity!!! - ask me why!) prior to installing. I expect this is a mechanical issue in any case.

If you have something like a flashlight to test batteries, that is best as some will give 1.54V, but not enough current to do anything.

Once upon a time, I came across a set of very, very cheap (from China) knock-off duracell (small D deliberate) batteries, D-cells in 4-packs. Of the eight batteries, two were "packaged" backwards - the button at the negative end, the flat on the positive end - one in each package. So, I ask.

Peter Wieck
Melrose Park, PA

On 12.04.2017 00:03, Cursitor Doom wrote:
Hi all,

Earlier I needed to do something with my graphing calculator. It only
gets used very rarely so I wasn't surprised when it didn't switch on. I
immediately suspected the batteries, but they were fine. All the same, I
slipped in a brand new set. Still nothing. In the battery compartment
they have an arrangement of 4xAAA cells in series to give a 6V supply.
However, on checking the voltage from 'head to toe' as it were (from the
first '-' to the last '+') I got a reading of minus 3V instead of the
plus 6V I'd expected. Checked all the connections and the probes in the
right sockets and whatnot: all fine.
I'm sure I've had this issue before with a different battery appliance in
the dim and distant past but can't recall what the cause was. It's like
it's too far in the back of my mind to resurrect any more. Can anyone
assist, please?

Hi,

If the calculator happens to be a HP 50g, make sure the batteries can
supply at least 100 mA without a lot of voltage drop. When initially
switching on and checking the memory, it needs that much. Also check
if the 3V lithium cell for memory backup is still good. If not, there
can be some memory corruption issue, in which case pressing the hard
reset key with a pin should clear it.

Dimitrij