Toshiba MQ01UBD100 - 2.5" USB3 integrated board, no power

[inflex]

Drive will not power up, will not draw any current. No externally visible damage, cables are in good condition. Tried with other cables.

Checking the (assumed to be) pico/LittleFuse (0603 'S' marked component on the right side of the USB connector) shows it as open-circuit. Diode mode on the left shows open; diode mode on the right shows 0.450V which seems reasonable.

'S' rating on the pico/Littlefuse is supposedly 4A rated.

Where I'm concerned here is that I would have considered it fairly difficult to blow the fuse at 4A without some level of down stream damage or potentially a reasonable short being present (unless it's part of the motor drive and not present until the BLM controller starts up).

I have no problem replacing the fuse but I'd prefer to hear if anyone else has encountered a similar situation before.

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[inflex]

UPDATE: After doing a lot more checking, trying to find any obvious shorts of physical damage under the microscope, I opted to remove the old fuse. Turns out that was the fault. The fuse itself was physically fractured on the right side between the black area and the capping.

Replacement of the fuse has returned the drive to functionality. Data being copied off to a new drive as a standard precaution.

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