19V on WD20EARS - Help finding TVS Diode

#1

Hi - I did the old Laptop PSU trick today and killed a couple of drives. One of them was a WD20EARS.

I have read the TVS FAQ and I imagine the 12V TVS is dead and needs to be removed. However I’m not sure which is the correct component to remove.

A picture of the board can be seen here…

Google Photos

Any other advice would be most appreciated.

Many thanks,
RzB

This forum is getting really boring
#2

Hello RzB,

The big guys down there at the SATA power connector (D3 and the other one without ID in the left bottom corner). I assume D3 protects the 12V line, but you have to use a multimeter to measure which one is damaged.

Brgds,
Dean

#3

Dean,
Yes - I thought they would be the ones.
Is there any reason why I shouldn’t just remove both of these…
I just want to get them spinning long enough to get the data off… I realise there would be no protection - but at least they might run.
If these diodes aren’t the problem I don’t think I will be able to fix anything else that might be wrong.

Oh BTW - any advice on getting them off - I do have a very fine soldering iron - or would it be best to just cut them off?

Many thanks for your help.
RzB

#4

Hi RzB,

Actually there’s no reason to don’t remove both of them. I understand your point, you would like to extract the data then you probably won’t use the drive anymore as a reliable data storage. The protection provided by TVS diodes and fuses (0 value resistors) is not bulletproof, you never know what else burnt. Even if those units are able to work for some more time, they could be dead soon.

Don’t cut them off please, you might damage the PCB. If you have a good soldering iron, try to hold the diode with a forceps and warm up the two edges with the iron until you can remove it without forcing it.

TVS diodes just the half of the protection, usually there’s a zero value smd resistor belongs to each of them / each of the power lines. One for the 5V and one for the 12V. You must short them with a piece of wire if they damaged. Check R64 and R67, but I just guessing, don’t take it serious and close them to short until you are sure. It’s also not 100% they burnt. You must use a multimeter to measure them. On my WD board the zero value resistors have a text with “000”. Probably the circle sign means the same on your board.

Brgds,
Dean

#5

Hmm - I don’t have a good feeling about this…
R64 and R67 show up as dead shorts on my multimeter.
Both diodes are Mohms in one direction and about 15k in the other.
I think that shows they are probably in good shape - yes/no?

Many thanks for your help,
Roy

#6

Hi Roy,

I suggest to desolder those two TVS diodes and try to start the disk without them. Then you can close this topic and won’t let you ask the same “what if” question from yourself each week.

Well… the fact is this protection given by TVS diodes is not a sure thing, it’s even not close to it. There are cases where they work well, but I read more about when not. There are sensitive parts on that board which might burn faster than the diodes.
Same in my case with the 6TB WD Red, the motor even not spin up, however removed the diodes and shorted the fuses (0 value resistors). Probably the motor controller unit damaged also (and who knows what else).

Best regards,
Dean

#7

Hi Dean

Success! Diodes removed and 25% of the data recovered so far!

Thank you so much for your help.

I have two more dead drives from the same incident - a WD3003FZEX and a Toshiba.

I’m about to remove the diodes D3 & D4 from the WD3003FZEX board.

Google Photos

I’ll let you know how I get on.

Thank you,
Roy

#8

Hi Roy,

Happy to hear that, good job! Please desolder both diodes from the other drives and don’t forget to check the fuses (0 value resistors). If they open (=burnt), you have to short them with a small piece of metal (for example you can cut the leg of a regular size resistor).

Brgds,
Dean

#9

Diodes removed from WD3003FZEX and data recovered!

Many thanks for your help.

Roy

#10

amazing drives…
btw good job!