I recently bought a 2.5" USB2.0 external hardisk case and a 40GB IBM Travelstar hardisk to go along. The case requires external power and came with a PS2 port connector to get the power.
Yesterday, I found that my friend's laptop does not have a PS2 port. So I thought I'll either buy or make a AC to DC adapter to power the hardisk. I measured the PS2 port and found that it gives out 5V. The problem is I don't know how much current the hardisk drains.
So, my question is
1. Does anyone know what is the max current drain a PS2 port can tolerate?..... or
2. Does anyone know how much max current does a IBM Travelstar 40GN (40GB) needs?
I believe the laptop has a USB port, just not a PS2 port.
I've never heard of an external device being powered from the PS2 port before. Have you put it together and tried it only plugged into the USB port? Maybe the PS2 connector is just in case you don't have a powered USB hub.
*Dual PIII-800 @900 i440BX and Tualeron 1.2 @1.74 i815*
OH, I misread it. I've seen keyboard powered devices, but that's really weird because the keyboard and USB power are both 5v, so why not take it off USB, unless it needs two power sources (yes, it's possible to spread the load).
<font color=blue>You're posting in a forum with class. It may be third class, but it's still class!</font color=blue>
Well the maximum power load a USB port can handle is 500mA (0.5A) and considering that a hard disk would almost certainly need more than that (My 20gig 5400rpm takes about 1A from 5v line) it would need a different source. I dont think you would be able to run it from another USB, but if you have a multimeter you could try testing the current draw from the other power source (put it through a 5v power adapter or sumthing), that way you would know if it would run from another USB.
I've never heard of an external device being powered from the PS2 port before.
I used to have a parallel-port web cam that you plugged into a PS2 port. (I suppose I still have it somewhere, laying around in the computer graveyard.) Only it was on a computer with an old AT keyboard port and a serial mouse, so I needed converters just to even use it. Heh heh. Still, I liked doing that more than plugging in an external AC adapter.