After all the stories I've read on this forum about stiction I finally came across a case yesterday that was a true stiction case.

A 7200.7 120GB was booked in, drive wasn't spinning up at all. The faint buzz on startup didn't sound like a typical jammed spindle, and motor winding resistances were fine. Tried another PCB to eliminate any such issues with no different result.

Upon internal inspection the heads were indeed parked half way across in the middle of the platters, stiction preventing motor spinup. Returning the heads to parking area was all that was needed, drive imaged 100%

What gets me is how this sort of incident happens in the first place. As soon as a drive powers off the heads move back to the parking area long before the platter/s have stopped spinning. The only instance I can think of is when a drive is dropped and the spindle jams, then I can see how the heads can park on the data area, but then you will have motor seizure as well.

Anyone have suggestions as to how this happens?

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Might have something to do with this

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Hello Nick

I think this could happen because of some kind of vibration. For example, if that hard drive was located near working DVD-Drive. When that PC power supply was suddenly turned off, drive started to move its heads back to parking area, but the same time DVD-Drive was spinning its motor and making vibration.

Don't know if this is a good example for you, but I think its possible.

Nick,

Did you use any sort of solvent on the drive to release the heads from the platters. I have yet to get a drive 100% imaged following a stiction issue, so I am curious about your process.

I think this might happen if the power is cycled in a certain manner. For example a power outage would cause the drive to park the heads whilst spinning down but if the power returns at a certain point the drive starts to spin whilst the heads were about to park and if the power goes off for a second time the heads might not return to the parking position.
eg. power is on then.......off on off
Maybe certain makes and models are more or less susceptible to this condition?

I blame sudden cut to power , hads moving to park , spindle spinning down, sliders lost air cushion and bam =) they land on the platters. However i may be wrong +)
Had a lot of cases where the freed heads imaged with no issues after. Neevr used any solvent. Just a bit of practice , steady hand and u need to know exactly what u are doing and apply the right ammount of force.
I have a force applied with a vector twards the parking ramp with 1 hand and at the same time counter clockwise on the platters.

The simplest way to release a sticky heads.

yup, just did a Hitachi about 1hr ago, stable enough that i cloned it with acronis... since my imager is tied up on a multi Bad sector Drive at the moment