ST3500320AS 7200.11 ... fried.

[zubin]

Hi All,

I made real dumb mistakes. First I didn't backup, second I plugged in the wrong power adapter into my external enclosure which contains the ST3500320AS 7200.11. The AC must have had the 5+ 12+ reversed. It was on for atleast 30 seconds to a minute till the horrid electronics burning smell... I thought it was the enclosure... I then connected to the right power adapter, except obviously now it doesn't spin up. The smell came directly from the PCB board. Pic below:



Seems like theres some discoloration along the traces. Theres a diode next to the sata power plug which is completely fried. I'm hoping nothing else has.

What are my options? Could I replace that diode?



Specs:
sticker:
-------
ST3500320AS
S/N 9QM37GWF
P/N 9BX154-303
FIRMWARE SD15
DATE CODE 08401
SITECODE KRATSG
WWN: 50000C5000CC11B84

on the PCB:
--------------
PCB 100466725
REV A DLAJ-4
GTC 12 V-0
0807-74-02

[rchadwick]

You don't even have to replace the TVS. However, based on your description, and the PCB, I suspect you might have more damage. Easiest way to find out is to just remove the TVS and see.

[zubin]

Looks like i'll give it a shot. I can't make out the markings if it really is the TVS. I'm only assuming at this point. But the one on the right (which looks like the same diode) reads DUJ and C747. Could anyone confirm if it is the TVS thats charred?

[rchadwick]

It's the TVS. There are actually two of them, one for +5V and one for +12V. It's a very good assumption it's a TVS. My word doesn't seem to carry much weight, so maybe someone else has an opinion?

[zubin]

Thanks, i'll take your word for it since i'm pretty sure it is also.

Oh haha, I meant no disrespect I should have articulated myself a bit better in my frenzy right now... but its comforting to have another opinion

[Russwinters]

rchadwick is very correct. The "diode" is a TVS "Transient voltage suppressor" which looks like (hopefully) that it did it's job well.


Remove the tvs, or replace it, and see what happens


good luck

[networkpc3000]

this is simple case. Zubin should be take action as well.

[zubin]

Well, I removed the TVS... hooked it up to my computer's internal power supply... turned it on... and nothing. Doesn't spin up. Looks like there was more damage then I thought.

The only good news though is that I have found a hard drive with exactly the same specs (except datecode) which will be coming this weekend. But I hear I must replace the rom chip on the donor PCB which sounds a bit complicated.

If it doesn't spin up at all after this, its very likely i'm going to go to a pro.

[zubin]

Just for documentary purposes, here's a pic of the TVS removed:

I'm curious as to which one is the ROM chip to be swapped?

[guru]

take the other one off on the far right

[zubin]

hey guru, I didn't think about that the other TVS being damaged. I took it off but... nothing still. Doesn't want to spin. I have a really bad feeling that its more than just the pcb.



If I swap the pcb with the new one coming on the weekend I will probably know. Question, should I immediately replace & boot with the virgin donor board, or connect the new harddrive first, let it boot, then swap out the pcbs? or does it matter? i'm afraid that the new pcb will write stuff on the original platter altering its state.

[drc]

No need to hot swap. Either its going to spin or not spin. ROM is probably one of those 8-pin surface mount guys but your pictures are too dark/blurry to read the numbers on them.

[pcimage]

100% sure you WILL need to swap the ROM, hot swap WILL NOT work.

Sean

[zubin]

I took a clearer pic of the 8 legged chips on the left (one is enlarged for clarity). Question is which one is the right ROM chip?

Also, I would first like to swap the PCB without replacing ROM to test if it will spin. Will this damage/modify the data on the platter?

[pcimage]

Yep, that's the fella!

It shouldn't change any info on the platters if it's wrong, and it will be!

I had two IDENTICAL drives from a RAID 0, and swapped the PCB's to test this.

Neither would work until I swapped the ROM, then they both worked 100%.

Sean

[thatdellguy]

http://www.winbond-usa.com/products/Nex ... -Guide.pdf

[zubin]

Just wanted to update everyone. I have just swapped PCBs and ROM chip however, the results have not been positive. Doesn't spin up at all. I can only conclude that there is some sort of damage to the internal motor/preamp/heads. Looks like i'm going to a pro for this. Thanks for all your help though guys.

[guru]

I would check your soldering ;o)

You can put the board back on your good drive and I bet it won't spin

[guru]

oh... Does the new PCB have Seagate on the main MCU(CPU) or LSI?

They have to match also or it won't spin :OP

[rameez]

Also check your orignal pcb on the donor drive if its powering up on that one u could have a motor/preamp issue .