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Is my calculator dead?
08-18-2016, 05:35 AM
Post: #1
Is my calculator dead?
Hi,

I started charging my HP Prime the other day to top the battery out for when school started. However, since then, it seems that it shows no sign of life. I have ensured that the problem is not my cable, and I started charging the battery when it was nearly full (or, at least, more than 50%) so there should've been power in it anyways.

The only thing that I can think of being wrong is the fact I accidentally charged it using a Samsung "fast charger" instead of a standard USB wall plug.

It's also been suggested that my calculator may have been bricked by OS 10077, however, I have not updated my calculator since I got it and I am fairly sure that version of the OS has never been on it.

Is my calculator dead?
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08-18-2016, 07:45 AM (This post was last modified: 08-18-2016 07:50 AM by matthiaspaul.)
Post: #2
RE: Is my calculator dead?
(08-18-2016 05:35 AM)Strontium Wrote:  The only thing that I can think of being wrong is the fact I accidentally charged it using a Samsung "fast charger" instead of a standard USB wall plug.
Don't worry, this can be ruled out. The whole point of using USB for power is to standardize on the power supply.

Technically, there is no such thing as a "USB charger" - they are actually just USB power supplies. It is always the target device containing the battery which contains the charging circuitry and which determines the charging current.

The external supply will just provide (more or less) stabilized 5V power. There are several ways how to "communicate" the maximum current the supply can provide to the USB device, some are standardized, others proprietary, some are dumb, some use active protocols, and not all methods are understood by all devices, but no matter how you combine them, the supply never has control over the actual current the device will (try) to draw from the supply.
If the communication fails, this will cause a standard-conformant device to draw not more than 100 mA even if the supply could provide much more - the consequence will be slow charging, but not damage. In the worst case, a non-standard USB device would attempt to draw more current from the supply than the supply is able to deliver; this will result in the power supply to be overloaded. A good supply will go into "overload shutdown" then until the error condition has been removed, a not so good supply will have a fuse burning, and a really bad supply (which would not be conformant with any basic electrical standards and which therefore would be illegal to sell) would catch fire by being overloaded. However, from the perspective of the USB device, the consequence of trying to draw more current from the supply than allowed under the circumstances would be, that the supply voltage will drop or be cut off. In no case will the device be damaged by plugging in a "too powerful" USB supply. If the device fails with a "too powerful" supply plugged in, the fault and the reason for this can be found in the device, not in the supply.

So, to sum it up, it is impossible that you did something wrong by using a different external USB supply.

Quote:It's also been suggested that my calculator may have been bricked by OS 10077, however, I have not updated my calculator since I got it and I am fairly sure that version of the OS has never been on it.
Since you didn't wrote, when you got your calculator, it is impossible for us to know if it could have been shipped with firmware 10077 already or not.

Greetings,

Matthias


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08-18-2016, 04:25 PM (This post was last modified: 08-18-2016 04:30 PM by Tim Wessman.)
Post: #3
RE: Is my calculator dead?
Does the calculator power on if you take the battery out and plug into USB? If so, stick the battery back in (while the cable is still plugged), leave it for a few minutes and see if the battery charged any. If it did, plug it in and let it charge up.

If it doesn't, you can contact support. If you are out of support time frame, a galaxy S3 replacement battery happens to fit and work properly...

TW

Although I work for the HP calculator group, the views and opinions I post here are my own.
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08-18-2016, 06:43 PM
Post: #4
RE: Is my calculator dead?
(08-18-2016 07:45 AM)matthiaspaul Wrote:  Since you didn't wrote, when you got your calculator, it is impossible for us to know if it could have been shipped with firmware 10077 already or not.

Greetings,

Matthias

He got the calculator in May 2015, approximately, which is way before OS 10077 came out. Since he didn't upgrade the calc since he got it, then it's not due to 10077

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