WD20EARX Possible damaged PCB

Hi All,

I installed a new power supply in my PC, tired to power it on and all I heard was a “tick”, CPU fan spun for a second then stopped. Unplugged all cables, plugged all back in and it powers on fine. BIOS only detects 2 out of 5 HDD’s.

After some lengthy troubleshooting I find that 3 of the hard drives will not spin, even tried on a different power supply, while 2 remain fine. One of them is a WD20EARX with firmware 00PASB0.

Even though I can’t see any physical damage to the PCB’s, is this most likely going to be the issue? Damaged PCB?

If I was to try to replace the PCB, what do I have to match on the doner drive? Just model number and firmware? Or date/place of manufactor/anything else?


See Q4:

In the case of your WD20EARX, examine D4, D3, R67, and R64 near the SATA power connector.

For the other drives, search the Internet for “TVS diode”.

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Thanks for the response. 

Just reading my first post back and its a bit unclear. The WD20EARX  is one of the drives that wont power on. Further investigation shows that “U1” on the WD20EARX has damage. D4, D3, R67, and R64 appear to be fine. 

U1 is the motor controller right?

Will replacing the whole board be the next logical step to getting the drive operational again?

It’s not impossible, but a straight board swap is unlikely to work. This is because each board has unique, drive specific “adaptive” information stored either in a serial flash memory chip at location U12, or within the Marvell MCU. In your case I expect that U12 would be vacant, which means that you will most probably be requiring professional data recovery services. :frowning:

That said, the SMOOTH motor controller is a multifunction component. Not only does it control the spindle motor and voice coil (VCM), it also controls the onboard DC-DC converters, specifically the ones that generate the Vcore and Vio supplies for the MCU, and the -5V supply for the preamp inside the HDA. If the damage to the SMOOTH chip is in the area of the DC-DC converters, then its possible that the preamp may be damaged.

See this thread:

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Thanks for your help, heres a pic of the motor controller, let me know what you think.


Unfortunately the damage is on the DC-DC converter side. :frowning:

L1, L2, L3, D1, D2, and Q2 are the components of the Vcore regulator for the MCU and the negative preamp supply.

You could try another board, but the chances for success are very low. Moreover, if the preamp is shorted, then it may burn up your replacement board.

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