| Forum Home | ||||
| Press F1 | ||||
| Thread ID: 77992 | 2007-03-30 02:56:00 | strangest USB crash - total lock-up | bill marek (12062) | Press F1 |
| Post ID | Timestamp | Content | User | ||
| 536942 | 2007-04-03 08:26:00 | You should not connect a 5v supply to the "second" USB "power only" cable end, if that is what you mean or frying of the laptop will result. My USB notebook drive case has a separate 5v power socket (which is center pin negative polarised just to confuse). When the external power adapter is used it disconnects the internal USB supply. But many USB notebook adapter cases do not have provision for an external plug pack, I made sure to avoid that type. |
godfather (25) | ||
| 536943 | 2007-04-03 08:40:00 | I'm assuming that the poster is correct in saying that the "Power only" connector is a USB one. Thus it's intended to get multiple (possibly 500 mA) gobs of 5V from USB ports to add up to handle the requirement of the drive. ... When the external power adapter is used it disconnects the internal USB supply. would seem to indicate that destruction of a laptop's supply is avoided when an external supply with non-USB connector is used. :D |
Graham L (2) | ||
| 536944 | 2007-04-05 03:44:00 | Good idea - as long as your computer has lots of usb connectors! Worth 'powering-up for. But I still am not sure if I can run two power supplies in parallel. Graham seems to think it is safe? (Sounds dangerous to me) Bill |
bill marek (12062) | ||
| 536945 | 2007-04-05 04:16:00 | Since the USB connector which handles the data provides 5v (as part of the USB system), if there is an extra connector (whether USB or not) for 5V I'd assume that the manufacturer has arranged matters so that using the second connector won't blow anything up. :D It's easily done ... a diode in series with each connector will isolate the supplies from each other, and the (around 0.2V) diode drop won't bother the electronics or disk drive motor. Have you got the instructions for any of the external drives? :cool: |
Graham L (2) | ||
| 536946 | 2007-04-07 05:15:00 | Hi, No instructions for the cases - very generic, very small, very cheap, work ok... The way the are wired - both the usb, and the usb-pwer - at one end of the cable with just a wire link, leads me to believe that there are no diodes isolating the two connectors. Good thought though! The diodes would have to hefty, wouldn't they - passing up to half an amp? Bill p.s. - theoretically speaking, could I cut just the power lines on the data usb connection, and run the power externally? |
bill marek (12062) | ||
| 1 2 | |||||