I thought I knew enough about PC hardware to perform a few simple upgrades. I was wrong. Please help me understand my mistake so I don't repeat it.
1. Bought a USB 3.0 PCIe card. Installed it. Saw that it took additional power, so I found a cable coming out of my PSU labeled PCIe. I snapped on an adapter and plugged it in.
2. Bought a hard drive, put it in my case. I had to re-arrange a few cables to get power to it, but everything fit in the end.
3. Power on, and I see a puff of smoke from one of my old drives. Power off.
4. Realize that when I re-arranged power cables I ended up daisy-chaining the drive to my USB 3.0 card, so I was powering the drive with the cord labeled PCIe.
5. Lament the loss of 2TB of data.
6. An hour later, realize that the 2.5" USB 3.0 drive that was pluggged in to my new USB 3.0 card isn't working. Tried it in a USB 2.0 port - nothing. Pop it open and sniff - toasty.
7. Lament the loss of another TB of data (maybe, I haven't taken off the SATA bridge and tried the drive directly).
So... How did I fry 2 perfectly good hard drives with my new USB 3.0 card? Did I use the wrong power cords? Is the card bad? Help!
PCIe power connectors are designed to deliver current to graphics cards, which require MUCH higher current than other cards and hard drives. A molex connector should have been enough to power the USB card, and a SATA connector directly from your PSU would have been enough to power the hard drive. Any PSU should have enough molex and SATA connectors for typical PCs.
Simply put, by using that adapter, you put way too much current through very sensitive components.
Not all bad, though. Odds are, the data on your drives is still intact, as the platters should be unaffected. Trying a PCB swap on the hard drives might work if the damage isn't too severe. Otherwise, you'll likely want to send the hard drives into a specialist to have the platters swapped and the data retrieved.
You'll need to buy the exact same model of hard drives as your fried ones to attempt a PCB swap.