WD2500BPVT - Short circuit?

WD Internal Drives Desktop & Mobile Drives
1

Hi all,

Suspected short circuit here, I’ve read a lot about the over-voltage protection diodes but can’t seem to find any on my board so was wondering if anyone could help out.

Drive: WD2500BPVT

PCB: 2060-771672-004 Rev A

Debugging so far:

  1. Laptop wouldn’t start (flashing lights).

  2. Removed drive and cabled to desktop (has worked with this drive in the past for recovery).

  3. Desktop PSU went in to over voltage protection.

  4. Removed drive, PSU came back to life.

  5. Opened up drive, removed PCB.

  6. Re-attached PCB only to desktop.

  7. PSU went in to over voltage protection again.

PCB image:

20150217_201241.jpg
20150217_201241.jpg2448×3264 2.53 MB

2

well you sayed everything :confused:

i cant see any burnt marks  wierd

3

@grandmasterphat, I can’t see any protection devices. If you mean that your PSU is going into over-current protection mode rather than overvoltage, then I would look for a short circuit on either of the Vcore or Vio supplies. To this end I would measure the resistance between ground and the L1 and L2 inductors near the SMOOTH chip. If these resistances are OK (ie not zero), then you can be confident that U12 is probably OK, in which case you would transfer U12, or its contents, to a replacement PCB.

4

Thanks for the responses!

@fzakar - Unsure which mode the PSU is going in to tbh. It gives the fans a brief kick then shuts everything down. I need to unplug the PSU to reset it otherwise it’ll refuse to power up again.

Measured L1 and L2 resistance to ground and all were positive resistances. I’ve had a look at replacement boards and all seem to be the same PCB revision but have a slightly different PCB-sticker number. Would that make a difference at all?

Thanks again!

5

The PSU is responding to a short circuit. If you measure the resistance between the ground and +5V pins at the SATA connector, you will probably see close to zero ohms. In fact you could simply measure the resistance of capacitor C59.

http://pinouts.ru/Power/sata-power_pinout.shtml

AISI, the short could be within the motor controller (SH6601, not SMOOTH - sorry), or perhaps U21 or U20. It could even be that C59 is the culprit.

As for PCB compatibility, I would think that the 2060 number on the PCB would be more important than the 2061 number on the sticker. Your PCB supplier should be able to answer that question in any case.

6

Thanks I’ll see if I can find a board that matches as closely as I can. The ROM doesn’t look too difficult to move so that may be the best solution.

Looking at the board some more I gave C59 a check and got ~73k Ohms so it would seem ok?

Thanks again!

7

Your measurements suggest that the short circuit is not at the +5V input to the drive. I can only imagine that it must be inside the motor controller chip, and that it manifests itself only when the controller attempts to spin the motor. In any case swapping U12 to a donor PCB sounds like your best option.

Best of luck.