Hard drive keeps system from initializing

[Chris42]

I have a very strange problem... want to see if anyone has heard of anything similar happening before.

I have a new Seagate 300GB drive which I installed one week ago after a previous drive crashed. It's been working just fine in that time. Tonight I was swapping drives (there are three total) to get the old drive in hoping to recover some data. At one point after swapping cables the system did not initialize at all... the POST never even started up (no signal at all to monitor, no keyboard, nothing). I found after unplugging all drives that only unplugging the new drive power would the make the system initialize.

So just plugging in the new drive power (with the data cable disconnected) somehow keeps the motherboard from working. Bad drive or power supply seems the obvious culprit, but neither shows sign of being bad. The drive seems fine, it spins up and I can hear the power-on seek of the heads. A voltmeter checking the power suppy finds absolutely no difference whether the drive is plugged in or not, the +5V red wire and the +12V yellow wire are unchanged (i.e. the drive is not shorting or overloading the power). Yet the system fails to boot up.

The system is a five-year old 800Mhz Pentium, so the power supply is getting old but I can conceive of no way in which it could fail quite like this. Any ideas?

 

[ski]

If the system consistently starts ok with the new HD disconncted, then the new HD is bad. Replace it under warranty.

 

[Chris42]

Thanks for the thought, that was my first reaction also. But the fact that the drive seemed to spin up fine made me wonder.

I tried the drive in an external USB enclosure and it worked fine there. Since replacing the drive and restoring most of 300GB is a pain I wanted to be sure it was necessary. So I bought a new power supply for the computer. Voila, the system now works fine with the new drive installed.

There's certainly a possibility that the drive was really the root cause, straining the power supply and the new one can handle it whereas the old one couldn't. But given the power supply was five years old I thought this was worth a shot, and it seems to have worked. I will be watching everything closely for the next two weeks (after which it gets a harder to exchange the drive, as I would have to send it to Seagate rather than just taking it back to the store).