ST500LX012 - Ultra Mobile SSHD - Short on PCB

[suricate.ch]

Hello,

I got one of those lovely SSHD drive. It was in a laptop and customer connected the wrong power supply, PC burned... HDD no longer spin. I get a BSY only on PC3K, no sign of life, no motor, no head noise and no terminal, so let's hope it's only a diode or resistor.

Is the schematic availaible somewhere ?

One of the component (cap ?) has 0V on both side. If I measure with diode mode, I get 0 on top and 0.8 bottom

Thanks
Suri

Attachments

[Lardman]

Is the schematic availaible somewhere ?

So funny...

I have a working one here, the diode is to the left of your picture, 1.7v is the same with a quick check although I'd need to recheck all the places you have measured. PCB on it's own draws a steady 0.26A. Is that a burn mark, hole or artefact on the chip?

[suricate.ch]

Thank you. The two diode looks ok.

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[Lardman]

It's not looking like a power problem. Try reading the rom in bootcode mode and posting it, the drive here is pretty sensitive about read speeds so you may need to experiment.

[suricate.ch]

With bootcode, I get the ROM (tried to unlock) but impossible to get anything on terminal.

[fzabkar]

I would measure the following test points:

[suricate.ch]

Thank you. Area near V1 is all 0.0V

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[fzabkar]

Can you provide a better photo of the area around V1, including the DC-DC converter chip? Can you tell us the markings on the chip?

[suricate.ch]

Thank you.

The Marking on DC-DC is

7188
418A

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[suricate.ch]

Thank you.

The Marking on DC-DC is

7188
418A

Attachments

[Lardman]

My PCB (100726606 REVA) is different around that area I have 10v floating about there on the diodes.

[fzabkar]

Check the enable pin (pin #1). If it is low, then the IC is not being switched on.

LX7188, Microsemi, 1.4MHz, 1A Synchronous Buck Converter, 2.5V - 5.5Vin, marking 7188, UDFN 2x2-6L:
https://www.microsemi.com/document-portal/doc_download/132768-lx7188-datasheet

[fzabkar]

My PCB (100726606 REVA) is different around that area I have 10v floating about there on the diodes.

V2 and V3 appear to be Vcore supplies (0.9V).

V4 (1.8V) is Vio.

I expect that V1 would be the 3.3V supply for the NAND.

The upper diode (KEZ) is a 5V TVS diode (SMBJ5.0A), so the voltage at that point should not exceed this value.

http://www.smdmark.com/en-US/search/code?id=ke

I don't understand the function of the diode nearest the motor controller. It is usually involved with the negative supply for the preamp, or a boost supply for the VCM circuit. In more recent designs there are two diodes for the micro/milli-actuator supply, at least in WD's case.

The MCU normally tells the motor controller to switch the preamp supply on or off. It may also control the NAND supply as a power saving measure. Therefore it could be that the MCU is dead, or the ROM may be corrupt. A ROM dump would be needed to rule this out.

[Lardman]

I expect that V1 would be the 3.3V supply for the NAND.

Looks like it as my ultra thin doesn't have it or nand.

It may also control the NAND supply as a power saving measure. Therefore it could be that the MCU is dead, or the ROM may be corrupt. A ROM dump would be needed to rule this out.

I wondering how you'd get a power related problem that deep onto the pcb without anything else showing any signs. Would it be worth monitoring V1 from cold to power on increase there is a blip at boot ?

I've said before I hate hybrids, corrupt nand or rom would sit better for me.

[fzabkar]

I expect that V1 would be the 3.3V supply for the NAND.

Looks like it as my ultra thin doesn't have it or nand.

It may also control the NAND supply as a power saving measure. Therefore it could be that the MCU is dead, or the ROM may be corrupt. A ROM dump would be needed to rule this out.

I wondering how you'd get a power related problem that deep onto the pcb without anything else showing any signs. Would it be worth monitoring V1 from cold to power on increase there is a blip at boot ?

WD drives do indeed "blip" the preamp supply on and then off. The OP did say that with "bootcode, I get the ROM", so it does appear that the MCU is alive, yet there is nothing at the terminal port.

I'd be looking at the ROM dump.

[suricate.ch]

I'll check, in the meatime, here is the SANYO ROM.

Attachments

W3N14E0L.zip

(434.76 KiB) Downloaded 299 times

[Lardman]

Couple of CRC's be they match the bad CRC's in a ROM I just grabbed from online.

[pepe]

It is normal to see nothing in the terminal if it cannot read the NAND.
So if supplies are alive, it can be nand.

pepe

[fzabkar]

Is this model supported by MRT and PC3000?

I notice that there is a NAND-less version of the same family, namely ST500LT032:

https://firmware.hddsurgery.com/index.php?manufacturer=Seagate&family=Angsana_5400

Does the SSHD PCB share the same MCU and motor controller (88i1067-RAH2 and 100723016)?

https://m.media-amazon.com/images/I/8186uqkbYyL._SL1500_.jpg

If so, try uploading a ROM from an ST500LT032 dump, after patching the adaptives. I can patch them, if necessary. Hopefully there are no NAND related modules in the SA. In any case, if the drive spins up, then this will narrow down the fault to the NAND.

[pepe]

I think it won't accept the adaptives coz they have different format.
But we will see that on serport at least.

pepe