I have an old iPod and charger. The charger plug is not polarized so you can plug it into an output in facing up or down.
Just the other day I noticed my battery indicator said low and I plugged it into the charger. But the indicator didn’t change to indicate it was charging. I jiggled all the wires and connections looking to see if there was a short or something. I even brought it to another outlet to see if the first outlet might have gone bad.
It turned out that when I reversed the orientation of the power plug, the ipod began charging again. And I checked again – plug in one way, and it charges; plug in the other and it doesn’t. The orientation of the charger never mattered before.
Why might this be happening, specifically the change in behavior? I can’t recall any similar experience with electrical gear before. Could it indicate some problem with the battery?
That’s an interesting problem. Since the plug isn’t polarized, the output side should be floating relative to the input (110 volt) side.
Offhand, I’d be a little worried that one side or the other of the input side is making an electrical connection to the output side, which would be a safety hazard. Any chance you have a multimeter, and can check for line voltage between the output conductors and wall ground? Check with the charger plugged in one way, then with it the other way.
Maybe someone else will have an answer that isn’t a safety hazard.
The charger can’t even tell the difference between the Active and Neutral pins , it can only know there’s 110 (or 220 or whatever) volts AC across the pins.
I cannot see how this makes any sense. Without a ground wire, the two wires see exactly the same thing–a current that varies sinosoudily. But I have no other explanation. Except for the contacts being slightly different.
I agree - it couldn’t be a problem with the charger, because a two-prong charger is floating and doesn’t know which wire is hot and which is neutral. The only explanation I can think of would be that its prongs make a good connection with the outlet slots one way, but not the other.
Could it be that the wire is broken and orienting the plug the right way causes the wire to flex and the broken ends to come into contact? You could test this by wiggling the wire around and seeing if it stops/starts charging.
Neither prong on the charger is visibly bent at all.
Tried in multiple outlets and on more than one power strip
See last entry. Can’t see how this could be the problem since no bending is visible and it works consistently from one outlet to another
Wiggling wires and connectors makes no changes with the plug inserted either way. It shows as charging consistently, or it shows as not charging at all.
There are two types of iPod/iPad/iPhone chargers there are tiny ones with squared flat ends that look like a cube, and more rectangular ones where all edges are rounded and the prongs fold up into the cube for travel. (Both have USB out the other side)
I suspect you have the smaller cube one. I think the rectangular ones are for higher-power items like iPads.
Anyway, I have found these Apple cube power adaptors incredibly finicky. Or trips overseas, I found I could plug them in several times multiple orientations before the device recognized it was getting power. (Using a plug adaptor, typically feeding it 220V instead of 110V). Even though they claimed to be 220V compatible they were not completely compatible. The rectangular ones never had a problem.
So yes, likely one leg of the rectifier bridge or the rectifier on one side or something has died, and it only works one way. Or… it’s just bringing out its inner finickyness.
I don’t do much electrical work, but I really appreciate owning a multimeter. Mine cost about $15.00 and if it stopped working tomorrow I’d buy another right away.
Elaborating on what someone else said, the tiny wires inside the cord on wall warts like these are really easy to break. The action that breaks them most frequently is winding the cord around the wall plug end when not in use. I used to teach physical science and one year we bought a bunch of multi-voltage universal power supplies like these http://www.pcrichard.com/catalog/catalog-product.jsp?prodId=AH50BR&cm_mmc=pla-_-NA-_-NA-_-NA&utm_medium=cse&utm_source=GoogleBase&KPID=AH50BR&c3apiks=195_13195&gclid=CNWcwZnlzL8CFRALMgod2G8AvQ for the electricity labs we’d do. Most of them didn’t live through the first semester due to people obsessively winding the cord around them after using them and internally snapping the wires right next to the strain relief thingy.
Please.
This is the second time this nonsense has been mentioned.
There’s no way that this is possible - on a two-prong device, there is no “reference,” so as far as the device is concerned one orientation is exactly the same as the other.
Are you sure? I-devices often take a few seconds to respond to a charging input, so wigging a bad cable and making intermittent connections might not show anything. Try this: plug it all in in the “bad” configuration and SLOWLY move the wire at the charger from one position to another, pausing for a count of three to five at each position.
All things considered from this distance, I’d say it’s a bad cable that only connects when the charger is twisted a certain way on the wire. Secondary, it could be a circuit flaw that genuinely only works with one ‘polarity’ of AC input, but like others I am having trouble imagining a circuit that would work that way. (Most small chargers are not transformer+rectifier+regulator based any more, though - they are switching types that more or less directly convert high AC voltage to low DC voltage. A flaw in the switching circuitry could produce this kind of polarity issue.)
OTOH, chargers are basically disposable and replacements are cheap…
One for the OP - is this a traditional iPod charger, I.e. a tiny cube with a USB port, the USB cable with older wide iPod/Phone connector as the only wire between the plug and the iPod.
One for Beowulff - why would an Apple iPod charge cube not work for several tries, trying plugs all over my Hong Kong hotel room in different orientations, then suddenly decide to work? (or at least, for the N. American version) And repeat this performance for several nights? I assume because the components and their output are so close to the limit of acceptable that it’s luck of the draw whether the digital component that detects charging accepts the signal or not.
Here’s probably a decent analysis of a charger construction, including circuit diagram:
it does use a diamond-shaped rectifier bridge; the setup is not completely symmetrical, and you can see the plug construction disassembled in a photo halfway down the page, the alleged live (vs. neutral) is indicated with a green dot - or is it the other way round?
Did you mean “does not use”? Because that page shows only a single rectifier diode, which is good enough to feed a switching voltage regulator from AC.
My iPod originally didn’t come with a charger at all – just a cable with a USB port on one end with and (I suppose) a proprietary Apple connector on the other, and the expectation was that I would recharge from my computer’s USB port.
Shortly after I bough a 3rd party charger (Griffin?, Geffen? – I dunno, I’m posting from work) that was just a little box with a folding electrical plug and a USB port. I plugged the original Apple-supplied cable to it instead of the USB port on the computer.
That’s what I’ve been using ever since – quite a while – my iPod is 7 or 8 years old (5th generation iPod Classic).