Question Diagnosing HDD PCB or motor failure (WD20EFRX)?

Jul 20, 2019
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I am trying to work out if my HDD is dead from a motor failure or PCB failure. there is no observable damage on the PCB. It failed while i was access data.

When i connect to a powered SATA USB, the usual spinning up doesn't happen and there is some buzzing sounds, repeated 3-4 times before nothing happens.

What i am trying to work out, is the motor dead or spindal seized, or is the PCB not giving the right power.

I have measured the voltage on the motor connectors on a healthy drive while spinning at normal RPM, its either at 3 or 6v depending on connector.

On the suspect drive while its trying to spin up and buzzes the voltage varies, but the voltages never get over 1.5v.

This seems to me to indicate that the PCB is faulty and not giving the motor enough voltage to get turning.

Is there any other way to diagnose if its the PCB or the motor, any locations i can measure voltage on the PCB to confirm its health?
 
Whatever diagnosis is, result is same as patient is dead as a door nail, flatlined, kicked the bucket, bought a farm....
Motor is controlled from PCB so by itself it can't be checked at home. It's a brushless , poly phase AC asynchronous motor at it's simplest form or a step motor,
If it's a SATA drive, even simple change of PCB is not so simple, there is a BIOS chip unique to every disk and has to be reprogrammed for it and that requires realigning it's logical data placement which again re quires specific HW and SW. Heads movement is by permanent magnet and an electro magnet, also non serviceable element.
 
You can measure the resistances of each of the 3 motor windings. They should be of the order of 1 ohm. The phase-to-phase resistance should be double the phase-to-common resistance.

It does sound like a stiction fault, though. Or perhaps the headstack is mashed against the loading ramp, which would be far worse.
 
Jul 20, 2019
2
0
10
0
You can measure the resistances of each of the 3 motor windings. They should be of the order of 1 ohm. The phase-to-phase resistance should be double the phase-to-common resistance.

It does sound like a stiction fault, though. Or perhaps the headstack is mashed against the loading ramp, which would be far worse.
Thanks, i have taken the PCB off the hards disc and measured the resistance between the four connectors for the HD motor in isolation from the PCB. The measurements are in the realm of 1.6 ohm for two of the windings, and 0.8 ohm for the third.
Anything else i can measure on the PCB in terms on voltage?
 
There should be 3 phases plus 1 common terminal. The resistance between common and each phase should be 0.8 ohm. The resistance between each pair of phases should be 1.6 ohm. I don't have any suggestion for PCB voltage measurements.
 

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