My wife's laptop flashed a BSOD and restarted itself one night. Upon restart, it would freeze at the Dell BIOS screen and go no further. I came to find out that the computer would not boot with the HDD installed. It took me three other computers to find one that would boot with the drive attached, but that computer would still not see the drive in the BIOS.
I sent the drive, WD5000BEVT-75ZAT0, DCM:HHCVJHBB, to Gillware. They quoted me a fair price for clean room work, but after calling three times, they would only offer "severely mangled heads" as a diagnosis. It wasn't worth the money to me, so I had the drive sent back and found a donor drive with the identical model/DCM to try a head swap.
My guru friend tested both drives before beginning. The donor was 100% OK. He put the "mangled" head stack into the donor drive and it worked perfectly, zero problems with any reading or writing. He then put the donor heads into the broken drive, and it would still not detect. Smelling a bad PCB, he tried switching them. The good PCB on the original drive detects at 2.2TB but sounds fine. (The original PCB caused faint but strange rythmic motor noises). The "bad" PCB on the donor drive also detects at 2.2TB and sounds fine.
So the questions are:
1.) Is my original PCB bad? If so, why does it allow detection on the donor drive?
2.) If not the PCB, then what?
3.) Since my original head stack seems perfectly fine, why did Gillware describe it as mangled?
Sorry for the length, and thank you to all for having a great forum where people really seem to know their stuff.