Seagate Momentus 7200.4 - Won't spin up after brief water encounte

[hourglass]

I have a 500GB Momentus 7200.4 in my HP laptop.

The way the drive is situated, it's wrapped in a thin plastic sheet which is open at both ends. The plastic sheet covers the PCB. When the drive is installed in the laptop the sheet (and thus the PCB) is facing down and is closest to the table or desk.

The HDD cover on this particular laptop has vents cut into it, and the cover is the lowest point of the case, so I don't see what good they do for cooling. Being that the vent holes are the absolute lowest part of the case, a small spill (such as kids knocking over a cup of water) goes right into the guts of the laptop. This particular spill put the water in between the plastic sheet and the HDD PCB.

Unfortunately, I didn't notice the water had gotten inside until the machine locked up due to the drive not spinning.

I took it apart and cleaned it all up then put the drive into a known-good USB enclosure.

• The drive does not spin in this enclosure or inside the laptop.
  
• Another known-good HDD works fine both in the laptop and in the enclosure.
  
• I measure 5V at the proper pins on the power connector.
  
• I measure 5V on one side of the TVS diode.
  
• The other side of the TVS diode references ground.
  
• The TSV diode shows 18K resistance. On a continuity test there is no connection.
  
• I've measured various other voltages on the PCB
  
• 1.8V near the EEPROM
  
• 1.8V and 3.8V on the pads for the head assembly.
  
• I'm not sure what voltages I should be seeing in which specific places, but these don't seem out of line to me.
  
• Using old-school knowledge without searching for specifics, I tried another Momentus PCB on this drive.
  
• It clicks and the drive spins up
  
• Having now read through this and other forums I suspect the clicking is due to either the wrong PCB rev or EEPROM.
  

With all that said, it acts like something is shorted, which isn't surprising since it got wet. However, I can't seem to find anything out of the ordinary. If anyone has any ideas of other things to check I'm all ears.

Ryan

Edited March 29, 2011 by hourglass