Q: Power supply of firewire HD feeds ATX power supply fan ?

[Darksoul71]

Hi,

I´m using an external firewire HD. Before I was using a 20 Gig HD for this firewire case.
The 20 Gig run without external power supply. I could attach the HD to my firewire card with a 6 pin cable and it worked like a charm. Now I´ve bought a 80 Gig HD and mounted it into my case. Unfortunately this HD sucked more power and I had to use the external power supply for my HD case.

Yesterday I switched off my PC and the fan of my power supply was still turning. I thought that my ATX supply
hadn´t switched of completely (this sometimes happens) and switched off power completely but the fan was still turning.

I thought "WTF is happening here ?"

After a while I pulled out the firewire cable to the HD from my firewire card and the fan stopped.
Seems to me that the firewire HD supply feeds the ATX powersupply fan via firewire cable and PCI bus.

Is this possible ?

Could this produce any damage to my PC ?

TIA,
D$

[UGAthecat]

as far as this being possible at all, from my experience it is. I used to have a scanner that plugged into parallel port and also had external power adapter. Whenever I turned the system off but left the scanner plugged in, the power and HDD LEDs on the front of my PC stayed on. I could completely unplug the PC's power cable, as long as the scanner was turned on the LEDs on the pc would stay on.

As far as it causing damage, well I couldn't tell you for sure. I would assume that it could cause damage, but I never had any problems with my system and scanner and I left it connected with power on for about 2 years before I replaced the whole system. You seem to be getting more voltage coming off of your external HDD than I was getting off of my scanner, so I would say that its more likely that damage could be caused in your case.

you might want to make a new friend at a local technical college where future electronics engineers are in training and have them check it out for you, they could probably build a choke for the firewire cable that would allow the drive to work and still kill the excess voltage.