Removed D4 diode, 1.0 TB Caviar Green now powers up but not detected when connected to PC

After removing the D4 diode from the PCB, my hard drive now powers on.

However…although my computer (Windows 7) detects a USB device being plugged in…no icon appears (ex. E: drive) under ‘My Computer’ which would indicate the hard drive is being detected.

The hard drive is a 1.0 TB WD Caviar Green. I’m using the original PCB with only the D4 diode pulled off. 

Any suggestions?

Here is a pick of the PCB before I pulled off the D4 diode?

Try sending a PM to fzabkar. If I rember right I think he recommended using a jumper to bypass the burnt diode. He is about the only one who understands these boards. 


You must not replace a shorted TVS diode with a jumper. That would amount to replacing a short circuit with another short circuit. The zero-ohm resistors sometimes need to be jumpered, but not in this case.

I would connect the drive via SATA in order to determine whether there is a problem with the bridge PCB.

I would also gently clean any oxidisation from the J1 contacts.

Oxidisation on Western Digital PCBs:



Why don’t you write up a little post about these boards and have Bill post it as a sticky. You are the only with any understanding of these boards.


Here is the PCB after I removed the D4 diode and used a soft white eraser to gently clean the J1 contacts.

  • I re-connected the PCB to the hard drive

  • Placed the hard drive in an enclosure (used SATA connection)

  • Connected enclosure to my Windows 7 laptop. 

(NOTE: The light on the enclosure turns on, I can hear the hard drive spinning, everything sounds as expected.)

  • I still do not see the external hard drive under ‘Computer’

  • Opened ‘Disk Management’ and I see the following:

(Does this mean the PCB itself is bad?)

Looks to me your PC is seeing the drive … Disk 1 , but it needs initializing (formatting,partitioning) 1st before it will appear under “My Computer”

Sorry, was there any “Data” on the drive ?  formatting won’t lose it, you should be able to recover most of user data recovery software.  but, you’ll need another 1TB HDD to recover to.

@Whopper, please DON’T format the drive. Formatting is data destructive. If you are able to recover your data afterwards, it will be in spite of formatting your drive, not because of it.

That said, the drive looks OK, but I suspect that you haven’t told us everything. When a drive shows up as “not initialised” or “unallocated”, it means that there is no partition information in sector 0. This could be because you have deleted the partitions, or it could be that Windows cannot make sense of the information.

Is the drive a My Book Essentials? If so, then the data will have been encrypted by the USB-SATA bridge board inside the enclosure. If you remove the drive from its enclosure and connect it via SATA or via a different enclosure, then Windows will see gibberish.


Fixed! You are 100% correct  fzabkar :smileyvery-happy:

Here’s the external hard drive case:


Here is the USB-SATA bridge board from inside the case:


Once I connected my hard drive (has the PCB minus the D4 diode) to the USB-SATA bridge board, then connected to my laptop, I can now see the drive and view my family photos again!

Thanks to everyone and many thanks to you  fzabkar!

yes it’s nice to know all the info before asking advice … otherwise you’ll get the wrong advice.

So, TheWhopper … are you gonna keep a back-up your  family photos from now on ?

or are you going to wait until the next drive failure ?   (which will be to late, and you might not be lucky the next time)

@TheWhopper Excuse me for digging up the topic. I have the same drive with the same issue.

Did you eventually solve it by removing the diode? Or replacing it?

Again excuse me for digging up.

Not a problem. I ended up removing the diode, put the hard drive back
together, then extracted the data. I lack the finesse to solder anything as
small as the diode…lol

Hi guys, new face here, i have this problem as well, but it is my case power supply that has shortet out.

My harddrive makes no sign of life once i put it in as a internal HDD, i hear another disc fall in rpm when i plug it in, but raises again and the wd green is just dead silent.

Will it help if i get another matching external case i can rip apart and plug the drive in? one that’s identical to the one i already have?

Hopefull new guy here! thanks

I have been experiencing this same problem and in reading some into how to solve it, it seems that youre the person to speak to. I have removed my D4 diode but my hard drive still wont come on. Any suggestions?

I have a WD30EZRS. Drive does not spin. I saw smoke coming from pcb and when I touched D3, it came off(and left a nice burn mark on my finger). I tried connecting again but no spin up. I checked R64 and its 0 ohms but R67 is open(I assume it should be 0 also). If I leave D3 empty and short R67, should it work?


Hi i have a wd1001fals 1TB black hard drive, the problem is that the drive is not spinning. What should i do? How to repair the board