seagate st2000dm001 FW: cc45 wont spin up

[pcpete]

This drive does have a bad 12v TVS diode based on it is has a near 0 ohm reading. It is not shorting between the 12v and Ground, so I am assuming some other device like a fuse or inductor is bad, and maybe other stuff. My understanding is one option is to get the same board and transfer the rom. Is it practical to try and figure out what other part may be bad on this pvc? Could you give me a bit of guidance or direction to look?

Attachments

[fzabkar]

Check the zero-ohm resistor(s) in series with the +12V supply.

Attachments

12V_TVS.jpg (73.53 KiB) Viewed 16287 times

[pcpete]

they both have an ohm reading of 1. Does that mean I can cut my TVS diode and then bridge the two tiny zero ohm resisters?

[fzabkar]

Is that 1 as in 1.0 ohm or 1 as in overrange? Do you get the same display if you hold your probes apart in the air?

[pcpete]

I don't think I did what you asked correctly. I just put the probe on each side of the resistor and read the ohm reading. Do you mean I should put power on it and see if I am getting 12 volts through it?

[fzabkar]

What you did was correct. All I'm asking you to do is to clarify the reading. Some multimeters display "1" when the reading exceeds the range on a particular scale whereas others display "OL". A display of "1.0" would correspond to 1.0 ohms.

Alternatively, and assuming that the PCB doesn't shut down the PSU (as your opening post would suggest), power up the PCB and measure the voltage on either side of the resistor. This will tell us whether the resistor is open circuit.

[pcpete]

when I hold the probes apart it show the same 1. The resistors have no continuity through them, I think that would mean the are closed.

Just curious, since their are two of the 0 ohm resistors, is one just redundant? They seem to be bridging the same area. Can I just bridge them with a wire like I showed in the diagram along with removing the TVS diode?

Attachments

[fzabkar]

Just flow a blob of solder over each resistor, and remove the 12V TVS diode. Then retest the circuit for shorts. If all is OK, then you should be good to go. For added peace of mind we can do more voltage tests prior to reinstalling the PCB on the drive. Let me know if you wish to do this.

[pcpete]

ugh. I am embarrassed with my soldering. I have continuity to the part shown in the diagram. I cant tell for sure if I see what is bridging them. I am pretty certain that is not correct. Or is that normal, are they both supposed to be on the 12v rail? Before I make a bigger mess, I thought I would get your opinion.

Attachments

[pcpete]

Sometimes I think I have trouble explaining myself. The 0 ohm resistor is on the 12v rail. That other, what appears to be a resistor, which I have the red line drawn to, is also on the 12v rail. Is that because I have possibly bridged it(I am not sure by looking) or was it always on the 12v rail? I am hesitant to put power on the pcb if I bridged something that was not meant to be bridged.

[fzabkar]

Your photos aren't very clear. If the two components are marked with a "0" or "000", then they are zero-ohm resistors and can be bridged with a solder blob. Don't allow this bridge to contact adjacent components.

Perhaps it would be safer if you were to purchase a replacement PCB plus firmware transfer for US$50 or so.

[fzabkar]

Can you measure the resistance between ground and each of V1, V2, V3 and Vboost?

Attachments

regs_2.jpg (57.41 KiB) Viewed 16155 times

regs.jpg (89.06 KiB) Viewed 16155 times

[pcpete]

first off, I am very grateful for your time and expertise. I have a picture with two red arrows pointing to contacts. These are both on the 12v rail. Is that seem normal or is that because I may have accidently bridged a connection between them while trying to blob the 0 ohm resistor

Attachments

[fzabkar]

Your PCB appears to be this one (P/N 100724095):

http://www.hdd-parts.com/15030504.html

There must NOT be a connection between points A & B or C & D. Measure the resistances between these points to confirm that this is indeed the case.

Attachments

[pcpete]

Thanks. That is a beautiful diagram. I suspected "d" had to have been the 5 volt, since it appeared to lead back to the 5v TVS, thanks for verifying that. What I think happened was I used a wired coated with solder to bridge the 0 ohm resistor and it must be touching "d" somehow.

[fzabkar]

I think the voltage I have identified as Vboost may in fact be the negative supply for the preamp. Sorry for the error.

[pcpete]

Thanks so much for your help. The drive is imaging as we speak. I ended up removing those 0 ohm resistors since I was having a hell of a time trying to bridge them, especially without causing a short to the 5v rail. Then I just attached a wire directly

Attachments

[fzabkar]

I guess that's another way to do it.

It would have been easier to run the wire to the +12V pins at the SATA connector.