WD2500BEVS not powering up

[jerkykid]

Hello everyone, I have a scorpio drive that I am trying to figure out. The drive will not spin up
at all. A few things that I have checked are...

Checked for power at what looks to be test points on the bottom side of the board
they are labeled as 1.2, 3.3 and 2 grounds. They all appear to be ok. I also checked for power at
the spindle motor connections...No power there.

Just reading through the forums I tried to see if maybe I am having a diode issue of some sort.
D1 and D2 came up with different results.

D1 resistance is 75ohms and 116ohms reversed
diode test with dmm is .062 with continuity one way .106 no continuity the other way

D2 resistance is 1.6K ohms one way and 7.4K reversed.
diode test with dmm is 1.96 one way and .171 the other no continuity either way

I attached an image of the board I am looking at. Any suggestions would be greatly appreciated.

Thanks

Attachments

[fzabkar]

The +1.2V and +3.3V supplies are probably the Vcore and Vio supplies for the MCU and SDRAM. These are controlled by the motor controller combo IC at U1. L2/D2 and L1/D1 appear to be the inductors and Schottky flywheel diodes (not TVS diodes) for two switchmode DC-DC converters. One supply should be the Vcore, the other will be the Vio. To determine which is which, test for continuity between the inductors and the test points. Obviously both diodes are OK.

I'd also measure the voltages on each of the pins of transistor Q1, and I'd also probe the voltages at the preamp connector. The pins with the heavier traces should be the preamp supply pins, and the two ends of the voice coil.

Is the drive identified by your BIOS? If so, then it could be that your drive is configured to Power Up In Standby (PUIS). PUIS can be enabled either via an ATA command, or via a PM2 jumper.

WD Jumper Settings Guide:
http://www.wdc.com/en/library/eide/2579-001037.pdf
http://www.jerryching.dyndns.org/Web%20 ... etting.gif

[pclab]

I had an WD5000BEVT with identical problem, no spin. I tried the PCB on another WD identical and it spined up. The donor PCB on the original HD, didn't spin up too. So internal problem, I think. I put it aside to later check.

[jerkykid]

Hello everyone,

Well I found a new board for this drive. It now powers up. Of course I cannot get to the data, but
I didn't expect to.

Can anyone point me in a direction to check the pcb? From what I understand the Marvell chip is the
motor control? Am I looking at pinning this out for correct voltages?

There is also a "smooth" chip on here. I am getting different voltage reading at the diodes that I previously
posted so there has got to be something I overlooked.

I am just looking to repair this drive to do it and learn it isnt a customer drive, but I would still like to accomplish
this.

Thanks Everyone!

[fzabkar]

These links will help you identify the components:
http://hddscan.com/doc/HDD_from_inside.html
http://www.users.on.net/~fzabkar/HDD/HDD_ICs.txt
http://www.users.on.net/~fzabkar/HDD/TVS_diodes.txt

BTW, I don't see any message where you have posted the "voltage reading at the diodes".

[jerkykid]

Sorry about that....I didnt post the voltages. Which components (or test points) can I check to see what has failed?
I am thinking if the spindle controller is bad there has to be a reason for it. Am I correct in assuming this is a good place to start?

Thanks!

[fzabkar]

Which components (or test points) can I check to see what has failed?
I am thinking if the spindle controller is bad there has to be a reason for it. Am I correct in assuming this is a good place to start?

I'd also measure the voltages on each of the pins of transistor Q1, and I'd also probe the voltages at the preamp connector. The pins with the heavier traces should be the preamp supply pins, and the two ends of the voice coil.

[jerkykid]

I measured Q1 and what I thought were the right pins for the preamp.

Attachments

[jono-ats]

Sometimes it's bad heads/preamp that keep a drive from powering up.

[jerkykid]

The only thing is, the drive will power up with a different donor pcb.

[fzabkar]

Q1 appears to be the pass transistor for a +3.3V linear regulator. The SDRAM is a 3.3V device, as is the vacant flash memory location at U12.

One of the two switchmode regulators, either L1/D1 or L2/D2 (probably L1/D1), supplies the +1.2V for the MCU's Vcore. A resistance check from a 1.2V test point to L1 and L2 should identify the relevant regulator.

I suspect that the remaining switchmode supply would be the negative rail for the preamp. However, your preamp voltage measurements don't show any negative supply, so maybe I'm wrong, or maybe there is a genuine fault.

With power removed, I'd test for continuity between the +3.3V test point and each of the preamp pins. I'd also test for continuity between the preamp pads and each of L2 and D2, or L1 and D1.

You could also compare the voltages against your replacement board.

[elecmor]

Hi all,

My hard disk was damaged by accidantly power inversion (5v and 12v pins on the connector), I checked 3,3v: OK and 1,2v: NOK.

as per previous posts, I checked the L1 and L2 and they are open I would like to know if replacing thoses parts will solve the problem, also I need to know the values since no things printed ont L1 and L2.

Regards.

Salah

[fzabkar]

If the inductors are open, then they will have been subjected to a sustained overcurrent fault.

Is R12 also open?

Is there a short between the +1_2V and GND test points? If so, then the MCU will most probably be dead.

Does either end of D2 have continuity with any of the HDA pads (J1)? If so, then this will mean that the preamp may have been damaged.

[Mr jiang]

主轴不通电就换一个板试试，你没有备件吗