Where's the fuse on this PCB?

[pclab]

Hi

I have a Seagate drive wich wont power up. The PCB is a 100475720.
I don't have any compatible PCB to test for now.
I have checked TVS and they are OK.
My doubt is: is there any fuse? Where is it??

https://www.dropbox.com/s/t5ddfntdl5dp7 ... 125810.jpg
https://www.dropbox.com/s/uri5p8jx6zaa4 ... 125802.jpg

Thanks

[fzabkar]

Have you measured the voltage test points?

[pclab]

Hi

Back to this HDD. Today I got a donor HDD. So I swapped the ROM, because I tought the problem was on the PCB.
But the same happens.
That is: The original ROM on donor PCB and it doesn't power up.
Tried the Original PCB with the Donor ROM, also doesn't power up.
Swapped ROM again (original to original and donor to donor) and the donor is OK.

Can a corrupted ROM cause this faillure?

Thanks

[michael chiklis]

I received few months ago a seagate drive with identical problem.
I realized that the 3 motor leads had been crushed by the customer, solution was to pull up them with a screwdriver to be able to touch pcb pads again.

Check if motor contacts touch pcb or not.

[pclab]

I have tested with the donor PCB with the donor ROM, and it spins and get ready.
Of course, can't ID right and makes some clicks, but it spins.

The HDD is a ST3500320AS

[pclab]

Yeap, still no way to regen ROM on these bastards...
Crap!

[michael chiklis]

Yeap, still no way to regen ROM on these bastards...
Crap!

Why AceLab do not publish an update for F3 ROM regeneration?
Are AceLab engineers able to figure a way how to fix F3 rom?

[michael chiklis]

Hey pclab, what do you use to solder rom chip?
Maybe rom pins are not good connected to the pcb, if so solder again using a bit of flux.

[pclab]

Hi Michael

I have used flux. I think it's well soldered, I have done a few ehehehe and on the donor it works..

[pclab]

Hi Michael

I have used flux. I think it's well soldered, I have done a few ehehehe and on the donor it works..

Now i'm confused.
Are you saying that the suposed damaged ROM from the drive you are trying to recover when moved to the donor pcb will make the donor pcb to spin and click ? If so it's expected.
If you move "damaged" ROM to donor pcb and if both donor and patient aren't spining with donor pcb with damaged ROM the Problem is with ROM.

No. Both PCB's with the pacient ROM can't make any drive to spin.

[pclab]

I will try to borrough a programmer and read the ROM.
I'll keep you posted.

By the way, if someone can REGEN the ROM, send me a PM.
Thanks

[michael chiklis]

If the chip is damaged he will not be able to dump nothing from it.
If chip is damaged most likely is because customer played with it or did try a DIY recovery causing further damage to rom.

[fzabkar]

FWIW, I have seen a fault that caused the "ROM" to become shorted. That's why I always recommend testing the Vcore and Vio voltages, or their load resistances, before breaking out a soldering iron. In the present case I would confirm that there is no short between the ROM's Vcc and Ground pins (8 & 4).