WD5000AAKS - Heads Move, Never Leave Loading Ramp

[lostmandan]

Hi All,

I have a WD5000AAKS drive that failed - spins up, rapid clicking, spindle slows down then speeds up, a few more rapid clicks, repeats, then spins down.

I've read many posts on this forum regarding this drive and came to the conclusion that my data (mostly videos) is not worth the cost of DR. Easy come, easy go as they say.

Because I am curious, I do have a question though -

Understanding the risk of destroying all chances or recovery, I opened the drive.

When the drive is powered up, I am noticing that the heads never actually leave the orange loading ramp. The heads move back and forth on the ramp, but never make it to the media. This causes the clicking. The heads seem free to move, so I do not suspect that they are binding on anything. Applying light pressure to encourage them towards the disk does work - it definitely feels as if the voice coil is driving the assembly incorrectly.

This strikes me as interesting because the other reports of this fault state that the drive should attempt to read the system area (SA) for firmware. In this case there is no way they are getting to the system area - they never get introduced to the disk.

My question is as such-
The SMOOTH chip drives the voice coil and motor. The motor seems to run fine. Do the experts on this forum concur that the fault explained above is likely a defective SMOOTH chip .. in that the voice coil driver is functioning but not properly? Has this been seen before?

I am very tempted to replace the SMOOTH chip for my education. I realize that my chances of recovering data dropped to nil once I removed the cover, but I am really curious to see if the SMOOTH is at fault.

Best Regards,
Dan

[BlackST]

1) the combo chip works fine as soon as the VCM is driven and the motor runs.
2) you opened the drive so it is contaminated but it isn't the worst problem you have right now...
3) "encourage" head movement by hands... the flying height between heads and platters is in the micron range.. OUCH !! and you know how BIG is a dust particle ?
The drive has major mechanical problem or something like that (shocked maybe?)
4) to remove and resolder the chip you need a controlled temp SMD reworking station with PCB preheat, flux and everything you need not to damage the surrounding components , and the chip is also heatsunk to the PCB. But trust me, it's working. Not the drive as a whole anymore, as it is a piece of junk now.

Conclusion : totally destroyed drive with maybe good PCB - you can sell the PCB on ebay , a pro can reprogram it .

[lostmandan]

As stated in my original post - the question is posed for curiosity sake, not data recovery sake. I don't care if the drive can be recovered or not.

1) Is there a possibility that the combo chip can be defective even if the motor spins and the VCM is driven? The VCM is definitely not driven properly. I haven't found datasheets for SMOOTH so I am not sure how much processing the chip does. If the main micro generates analog signals that SMOOTH servos use without additional processing, then maybe the micro is at fault. Alternatively if the micro communicates over a bus and the SMOOTH has its own microcontroller/logic to interpret instructions into servo action, then it would be possible that SMOOTH was not working properly.

To over-simplify - if one switch in a motor H-drive circuit is open, the motor can only rotate in one direction. My thought is if the VCM driver is partially damaged (still don't know why it would be) then one failure mode could be improper drive/low drive current/etc. I'm speculating, of course.

2) Yes, I opened the drive. The alternative would have been to get warranty replacement. I didn't want the hassle of replacement, and don't trust these drives much after reading this forum. Given the state of the drive, I decided to take a closer look. No crime there, IMHO.

3) Yes, I did gently "encourage" head actuator movement I didn't allow the heads to reach the platter. I am not stating this as a viable method of getting a drive to function properly. It is a delicate system so obviously it is not advised.

4) Yes, I am familiar with SMD rework. It seems difficult to find a replacement IC. I wouldn't spend money on it anyhow.

I have no way of knowing that the PCB is good, otherwise I'd offer it up on eBay or elsewhere. I suspect it is defective in some way or another.

[pcimage]

If the drive spins up, then the motor chip is 99.9% OK.

Very good chance the heads are bad.

Sean

[lostmandan]

Cool, thanks Sean

What threw me is that they don't even travel over the media. I figured they would get there at minimum. I learn something new every day

If the PCB is OK then I don't want to throw it out. Is this something that the pros would be interested in? I'm not looking to make any money on it.. maybe a coffee or something

Thanks again guys!

[harddrivespecialist]

There is probably a damage to a ramp or head/s. This could cause a problem of unloading.
If you have forced them out, most likely you have created damage to media.

If data worth very little to you, get yourself a new drive and move on, otherwise be ready to spend big bucks for recovery.

[BlackST]

1) Is there a possibility that the combo chip can be defective even if the motor spins and the VCM is driven? The VCM is definitely not driven properly. I haven't found datasheets for SMOOTH so I am not sure how much processing the chip does. If the main micro generates analog signals that SMOOTH servos use without additional processing, then maybe the micro is at fault. Alternatively if the micro communicates over a bus and the SMOOTH has its own microcontroller/logic to interpret instructions into servo action, then it would be possible that SMOOTH was not working properly.

To over-simplify - if one switch in a motor H-drive circuit is open, the motor can only rotate in one direction. My thought is if the VCM driver is partially damaged (still don't know why it would be) then one failure mode could be improper drive/low drive current/etc. I'm speculating, of course.

No . THAT chip that is not called "SMOOTH" works in a very different way, I know EXACTLY how it works so I am 99,9999999999% sure about what I said.
Anyway, it's no problem anymore.

[beto]

If HDD spins but heads never go out form the parking zone, maybe its not doing contact PCB with MHAor if u remove it before maybe magnet its causing that , did u screw? before?

[N.C.]

Hi,

My bets, in the right order:

1. 1 or more head(s) gone/in the magnet, and the MHA is stucked in the ramp caused by height mismatch
2. as beto sad, yes, can be contact to the PCB is corroded.
3. pcb problem (not chips)
4. VC motor or its soldering is bad/open
5. VCD's one output FAT is bad
6. ROM problem

But agree with BlackSt, this is not make sense, because the drive is allready KO by the user.

Janos

[thatdellguy]

When you took off the hd cover did you put the head stack screw back on before turning on the drive? Maybe you could post a video?

[N.C.]

OK, i have read precisely the original post, in this case the 4th point is closed out.
Maybe the 6th too.

Janos