[SOLVED] WD Red Harddrive PCB defect after short (burnt)

[stratege-0815]

Hello,
I was linked to the article https://forums.tomshardware.com/threads/wd-burnt-pcb.3471470/ by google but it is closed.
@fzabkar I am referring to your statement in the article I linked above.

But let me start from the beginning. I had a raid5 array consisting of 4 WD RED 2TB drives. As a volume of 5.8TB I used this in windows7 running an adaptec controller. Somehow I managed to create a short in my computer and two discs from the same active backplane now fail to spin up. As I need at least 3 discs running to get the data from my raid volume I have a problem now.

You can see the PCBs on both drives on the right side are burnt

Am I right that the burnt chip is the motor controller IC ?

both chips look like this

I already bought a new matching PCB and the next step would be to swap the bios chip, but then I found the information from the article linked above "Unfortunately, due to WD's woeful "protection" circuitry, this means that the preamplifier on the headstack inside the drive is most probably damaged."

Does it make sense to try the PCB swap anyway? Or is the chance of an undamaged preamplifier that little that I need someone else to open the disc anyway?

It would be helpful if one could give me an estimation of this situation.

(sorry for my bad English I am writing from Germany)

Best regards
S

 

[fzabkar]

If diode D3 is shorted, then this means that the +5V input was overvolted. This in turn means that the preamp may be damaged.

I would measure the resistance between ground and pins 1 & 3 of the HDA connector, J1. I believe these are probably the supply voltages for the preamp. Do this with the PCB on and off the drive, or measure the pins at the HDA connector on the drive's base. This will tell us if there is a short inside the preamp IC.

The following tutorial should help you to understand the terminology:
https://hddscan.com/doc/HDD_from_inside.html

If the preamp is not damaged, then a PCB + ROM swap should recover your data.

You can compare your resistance measurements against your working drives.

I believe these preamp test points can be accessed at the bottom of the PCB.

 

[mdd1963]

DId you per chance swap PSUs but attempt to reuse old (often incompatible mixing between PSUs) modular cables, which can often quite quickly burn up all storage units at first power on...