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Fried TVS diode on PCB?

This seems like the most knowledgeable place to ask about this, so I figured I’d ask about removing this TVS Diode I highlighted. I saw a video repairing a dead drive (not spinning up at all) by removing the burnt out TVS diode >https://www.youtube.com/watch?v=03Laq4z4trU.

The highlighted one (D3) in my image is reading dead on my multimeter in diode mode, while the D4 reads fine. Should I go ahead and remove it, or are there other components I should check while I have it open?

Thanks in advance for any help, and from the looks of what I’ve seen here I should also @fzabkar when it comes to this kinda thing.

Measure the resistance of R67. This is the zero-ohm resistor to the right of D3. If this resistor is open circuit, there is a real chance that the preamp on the headstack has been damaged.

R67’s reading as about 31 ohms, assuming I’m reading this thing right. (set it to beep mode, read 31 ohms while it beeped.)

That’s bad. :frowning:

The drive may have internal damage:

http://www.hddoracle.com/viewtopic.php?p=5033#p5033

To be absolutely certain, what resistance do you measure when you touch the probe tips together?

Probe tips gives me 0/0.1 ohms.

Luckily the drive’s not filled with anything too irreplaceable, so if I’m SoL, I can live with it.
Is this the kind of fault I could attempt to fix with a PCB swap, moving over the bios chip and all that, or should I just write it off?

EDIT: Read some more, yeah I’m guessing that’s a no. Headstack’s separate from the PCB :sweat_smile:

Is there a burn mark on the motor controller IC?

The fact that R67 was not completely open gives you some hope. What resistance do you measure between +5V and Ground at the SATA connector while the PCB is on the drive? You need to remove the shorted diode before performing this test.

https://pinoutguide.com/Power/sata-power_pinout.shtml

Nothing looks particularly burnt, and I’m measuring ~32 ohms between those pins (With the diode removed)

Can you repeat the same measurement with the board off the drive? If you get the same reading, then the motor controller is probably responsible for it. Otherwise, if you get a much higher reading, then the preamp is the culprit.

With the board off the drive, I’m getting essentially identical readings, so it sounds like it’s the motor controller.

If you decide to try a replacement PCB, the ROM at U12 needs to be transferred from patient to donor. Hdd-parts.com will supply a PCB and transfer the ROM for US$50.

Thanks a ton for all the help, I’ll definitely give those guys a shot if it turns out I’m forgetting something important on this drive.

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