Hi!

I've got a WD 3200AAJB hard drive with a dead PCB. I've bought a drive with the same circuitry, but couldn't find the often mentioned U12 ROM chip, so thought that the one with the U4 marking was the one, so I got it off with a hot air gun and replaced it. Well the fried drive was still dead, so I put mr. unit U4 back on. Now I'm at square one. So, my question is, which SMD unit shall I replace in order to breathe life into the new circuit?

The fried PCB:
http://yfrog.com/0ep5215668j

Thanks!

The big square one in the middle with the 'M' on it.

_________________
Zero Alpha: zeroalpha.com.au
Find Cheap Donor Drives App: https://www.zeroalpha.com.au/donor-drive-app Updated February 2026

Thanks for your fast answer Alpha. Whats the general thought on that. If the SMOOTH and that smaller chip died from a current overflow, did Mr. M survive that shock?

Well what you are doing has a high risk of failure. I would do things a lot differently and have a high risk of success.

_________________
Zero Alpha: zeroalpha.com.au
Find Cheap Donor Drives App: https://www.zeroalpha.com.au/donor-drive-app Updated February 2026

The big "M" chip has masked ROM inside which contains critical information. Unless this info is transferred to the new PCB- which is a task for a professional- you will get nowhere with this recovery. If you possess excellent soldering skills you can always remove and re-solder the big chip to the new PCB, but this method carries high likelihood of screw-up. If PCB is the only problem the cost of recovery should not be particularly costly.

There are also other nasty parts (a little bit hidden) that could have suffered.... :S

Anyway, if you want to tinker and likely destroy everything just for fun you can do it, otherwise it's just like msurgeon said, at that level (if the problem is only at pcb level) it is NOT an expensive recovery.

In addition to the SMOOTH and Sunplus (?) chips, there appears to be a blister on the zero ohm resistor below R67 near the power connector. I suspect that the diode below it may also be shorted.

U4 is associated with the jumper block. I suspect it is probably a resistor array.

I would think that the Sunplus chip would get its power via the +5V rail, and the SMOOTH chip would get the bulk of its power from the +12V rail. If that is the case, then the "shock" must have hit both rails. Therefore it may be an idea to check both TVS diodes and resistors at the power connector.

I would also test for shorts between ground and the 2.5V (?) supply to the SDRAM chip. Also test the Vcore supply to the Marvell MCU. I'm not sure exactly which point to check, but it should be one of the inductors around the SMOOTH chip, probably L2 or L1. While you're there, check L7, L11, D1, D2, Q2, Q3, Q8.

D = diode
Q = transistor

The results of the above tests may help you determine whether there is a chance that the MCU is still alive.

So the PCBs are not the same P/N...



SMD rework station or blower at 300+ deg. C for paint stripping ?




No wonder.



Million $ question.

Thanks for all the answers. We've got access to all kinds of hi tech gear. We put the Marvell chip on the working PCB, but the drive was still dead. So we put back the original Marvell, it worked like a charm.

So if anyone can make the dead drive and the working PCB work together, drop me a PM, and we discuss the pricing, etc.

That's better . In Hungary contact N.C. (Janos) or pepe from this forum.

capcapara,

For this type of WD and many others of same vintage, drive will only spin if heads
are electronically good (e.g. no short on heads electronics - hidden nasty parts)

In your case maybe your pcb you made was perfect but if the heads are electronically bad,
then the drive will not spin, leading to possible conclusion that pcb is bad, when it might be good.

Do some tests to confirm that drive spins with similar good working donor board.

Then you need to get heads replacement as well as create new pcb.

btw. To create new pcb - all "professional" does is click a few buttons on keyboard like
"ROM Restore" in an expensive program then program makes new board for "Professional"
(it's easier than typing two lines in a word document.)

A real 'Professional' was able to do this way before 'ROM restore in an expensive program' was even available. Real Professionals work hard developing methods to do this.

Not all of us are dependant on 1 click solutions.

I guess that maybe you are

hddguy wtfiyc? having another bad day at the office?

Your percepton of the real professionals is seriously flawed. Maybe you've got some grudge against Data Recovery or something?

Or maybe its all a front to disguise the fact you clearly have no real knowledge of it

Is not a program , is HW+SW tool . And is not a one click solution, you should know.

Hi BlackST

hddguy wrote one click on his HW-SW complex
I wrote "a few buttons" Why? cause i know. but I don't use it.
How? Cause I see it at places. Where? not important.

capcapara - did you establish if heads are electronically OK?

This was in response to your 'Rom Restore' reference.



Like Youtube maybe??

No offense, but barely knowing what you are doing with PCB and finally getting it to work, at the same time risking killing the whole thing forever - you can't really charge money for it lol.
Companies who do data recovery charge very little for this type of job, here is why:
1. They have bunch of donor PCB is stock, they don't need to buy anything
2. If PCB is completely dead, they have a way to automatically restore ROM from SA data, even if they never got a PCB whatsoever
3. If board is not completely dead, they can extract ROM data from the PCB and then program it into a new one.
4. Even 2 and 3 are unavailable (rarely), they have experience and professional tools to quickly fix the problem without risking killing the thing.

I mean, if you are going to do it for $50-$100, then yeah, who doesn't really care about the data can try it. Just spend some more time fixing those problems, get some experience, then offer this service on a more professional level.

Absolutely agree. We fixed those problems probably before you even heard of data recovery, using tools like programmator and researching each small part of a PCB in order to find out what it stores and how to develop professional solutions for 'other guys'

Hi porthas,

oy, yoi, yoi, yoi, yoy - you need a holiday - a long one.

...... researched each small part of a pcb to find out what it stores ...... What did you find?

Please tell us all what you found in these parts and how this helped you to "fix those problems".