17 May 2013

And Then, A Charge….

Are you the proud owner of a Nexus 7 tablet like wot I be?  If so, at some time, you may run into a problem I encountered last week. Charging.

The little beast, from new ‘till one day last week, would charge, using the mains charger,  from zero to hero in a tad over two hours. Suddenly, through forces not yet understood, it started taking close to twenty hours.  Bummer eh?

The Web-a-Net revealed many folk experiencing the same problem with only a few solutions none of which worked for me.

As a last resort I resorted to, ‘You could always try this’ Number 24.  This entailed removing the back, disconnecting the battery and, after thirty seconds, reconnect and stand back in amazement at the charge speed improvement.

Guessing at the fragility of the internals of this little guy, and noting there’s only room to get a fingernail round the back of the back to ease it off, I approached the removal with great patience and extreme caution.

After thirty seconds, with patience exhausted and caution thrown to the wind, I managed to remove the lid, roughneck style, with the help of my usual ‘delicacy required’ tools comprising of the usual small pinch-bar and a lump hammer.

I then pulled out the battery connector, let time pass then reconnected. I then replaced the back which took quite some time as it now resembles an incredibly complicated jigsaw puzzle.

The charging result? No change and, looking at the back, I’m guessing another warranty voided.

As that was a last resort, I decided to try an absolute last resort and I can’t stress strongly enough the extreme technicality of this last of all last resorts!!

I plugged the charger into the tablet, switched on the mains, pulled the lead out of the tablet, rammed it back in, pulled it out again, rammed it back in again, shook it all about and waited.  Guess what? It’s now charging in about three hours, zero to hero.  okay, not what it was but a whole hell of a lot better than waiting a week.

So there you go.  And why is it, and we never learn, that the least complicated, last idea we try almost always works?

Finally, for Friday, a little bit of Yee Haw I stumbled over to cheer you into the weekend. From that TV soap thingy Emmerdale, it says.  No idea, but it do say so.

Quote;  Douglas Adams.

“The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at and repair.”


Ripper said...

Its a faulty charging socket, usually caused by a dry solder joint on the mainboard. Happens a lot with tablets and laptops. Sooner or later you will have to bite the bullet and return it for repair.

Mac said...

Thanks; I did run across that possible/probable cause during my searching. Another popular reason relates to many people, including me, seeing this problem start after an Android OS update. The feeling is the update possibly contains a bug which results in it not being able to differentiate between being charged via USB cable to a computer, low amperage, and the mains charger, higher Amperage. A lot of people seem to be waiting/hoping for an Android bug fix. Mean time, getting rough with the connector seems to be helping. More an' on.

Ripper said...

Yes, on second thoughts the most probable cause is the droid bug. However I'm intrigued by your discovery of being rough with the connector, which seems to contradict that. Other than that, the USB socket of a desktop PC has a full 5 amps at its disposal, more than enough to compete with the wall charger. A quandery indeed.

Mac said...

Thanks again. Getting rough with it? My simple mind just thought that being rough with the connector, while powered up, I’d possibly confuse his brain and get a magic reset. See how technical I can be?? One point; the connector is a little sloppy even when roughly rammed all the way home and you could see the connector 'bending' to the minimal cable weight so I’ve taken to ensuring the cable has a ‘straight and supported lie’ when charging. So the improvement could be down to being rough or it could be using a non-sloppy straight lie. The obvious thing to try, and I will, is to charge with the cable unsupported and see how he goes. Later, I will.
If a PC USB port has 5 Amps available, one wonders why ‘they’ don’t utilise 2 Amps of it rather than just the 1......

Ripper said...

Your question prompted me to make another little discovery. In a desktop PC the power supply unit typically puts out 5v at a max.5 amps. However, and I didn't know this, the USB ports are not directly wired to the power supply, instead they are 'current limited' It varies between manufacturers, the average current being around 500mA. Some devices are limited as low as 100mA.

I can't understand why USB ports have this current limiting, unless its for protection purposes. Any current limiting circuitry is usually inside the device being charged, so if it takes 1A to charge it would do no harm to connect it to a port with 5A capability, the current draw would still not exceed 1A.

I can see I have not been of much help to you, I originally thought it would be a simple fault.

Mac said...

Thanks again. Please see the latest post.