Headline says it all. I got no power when I plugged it in. Then I removed the Barracuda hdd from the case and attached it to my Thermaltake - again no power. I'm thinking/hoping it's the PCB. I would like to check and possibly disconnect the diode... but being totally inexperienced at this sort of thing, I have no idea hope to start - or, for that matter, where it is. I can probably find someone to help me with the electrical stuff - but need to know where to point. So could please give me some direction and help me "possibly" save 3 years of data. (The irony is... I was planning on backing everything up when this incident occurred.)
I've included an image of the PCB.

Thanks to all and stay safe!

Your HDD appears to support the Power Disable feature via SATA pin #3. If your SATA power cable incorporates +3.3V wires, then snip them.

Power Disable Feature (SATA 3.2+ / 3.3):
http://www.hddoracle.com/viewtopic.php?f=46&t=2094

The 5V TVS diode is the part marked "15 NE". The 12V TVS diode is marked "6LF".

Also check the two pairs of zero-ohm resistors near the SATA power connector.

_________________
A backup a day keeps DR away.

According to the Seagate manual, pin 3 is "3.3V power, pre-charge, 2nd mate" Is that the Power Disable feature that should be snipped - or covered with rapton tape (as I heard is another possible fix)? The hdd itself is labelled "SATA AF."

Seagate's product manuals aren't always accurate. Try the tape, but also measure the diodes and resistors.

TVS Diode FAQ:
http://www.hddoracle.com/viewtopic.php?f=100&t=86

BTW, Seagate's enclosures are configured with a sector size of 4KB, so don't be surprised if you can't see your files in Windows. Instead try a data recovery tool such as DMDE.

Just FYI, there is an 8-pin IC and a 6-pin IC near the SATA power connector. I suspect that these are the load switches for the 12V and 5V supplies, respectively. That is, when the Power Disable pin is active, these two load switches would be switched off.

_________________
A backup a day keeps DR away.

This may be a stupid question... but given the 4KB sector size (and if I do get it powered up), would it be possible to just put it in an equivalent enclosure? Are there such beasts? (The original Seagate one is unusable.)

AFAIK a replacement 4KB enclosure should be fine.

_________________
A backup a day keeps DR away.