Quote:
Originally Posted by DaleDe
This is fairly normal. Just because a connector fits doesn't mean that it will work. In particular devices that use USB may have special logic in them to sense when they are hooked to a computer and when they are hooked to a charger. There are no standards for the logic hardware and thus these kinds of semi-smart chargers will not work on anybody else's unit and a unit that requires semi-smart chargers are likely only to accept their own.
Dale
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With the PRS-505 that I own, it charges from some PC USB ports, but not others, even on the same PC.
When testing the PRS-505, plug it into a USB port, and wait. The screen will show the "Spinning Arrows" logo, then the "Connected to USB" logo. Within a second or two of the "Connected to USB Logo" the LED should do something. If it flashes yellow, the goes red, that's charging. If it stays out, that's not charging.
On my Authoring machine, some USB ports (on the front of the case) draw power from the motherboard. These work. I've never installed the Sony S/W on any of my PCs, but it does recognize 3 card readers when I plug in the PRS-505.
Also on my authoring machine, I have some ports that are on a 5.25" drive hub with a card reader built in. The power here comes directly from the 5.0V power rails in the machine's power supply, so they provide 5.0V DC. These ports sometimes show the USB power is exceeded, because that error message comes from the device, not the PC. Devices sometimes sense a voltage of 4.9V to 5.0V and freak out. USB is actually supposed to be 5.2V to 5.3V. These ports do not charge my PRS-505.
When the PRS-5050 refuses to charge, it will show the "Connected to USB" logo on-screen, but the red light never turns on.
I have a 12V cigarette lighter to USB power converter that I got off eBay. It charges my PRS-505 in my pickup. IT WORKS HERE, SO THERE'S NO INTELLIGENCE REQUIRED.
I've tried a cheap eBay 7-port blinky powered USB hub. It does not charge the PRS-505 on its own. Even when I plug the hub into a PC (Fujistu Stylistic 3400 Tablet,) and the PC recognizes it, it does not charge! Plugging the PRS-505 directly into the same PC causes it to charge. Plugging the PRS-505 into the Hub after pulling the external 5V power supply form the hub causes that darn red light to come on! (The problem is the voltage.) The connection from the PC to the hub is a A-MiniB USB cable (same as the PRS-505's cable.) That cable works to charge the PRS-505 when connected directly to the PC, so the problem is definitely the hub.
I've tried the $9.99 Wal-Mart x4 AA USB power supply, and it does not charge my PRS-505. With heavy duty batteries, the green status led on the power supply dims and goes out after a few seconds, then turns on again, and repeats. With alkaline batteries, it stays green, but the PRS-505s red LED never comes on.
Most PCs charge my PRS-505.
I have several different models of 120V AC to 5V DC USB power supplies. None of those work.
Even on the systems that do charge my PRS-505, not all cables work. The roll up cables do not work. (Even the one included with the Wal-Mart x4 AA charger does not work.) It seems that the good quality cables work. This is not unusual - I've got several 2.5" USB HDDs that only work with certain cables. I've got a nice USB cable tester, but it only does A-A and A-B cables. It does not do A-MiniB cables. I do have the connectors laying around - I could build an adapter if I were bored, and I have 5 hours of sitting in a computer lab before the university gets out for Christmas. Unfortunately soldering irons are frowned upon in that lab (due to my past activities.)
I also need to build a USB-Mini-B-Female to Volt-Meter adapter to find the magic voltage.
It's the voltage, not some logic in the PC. The coaxial power plug next to the USB is labeled 5.2V...maybe it needs about 5.2V?
Andy