Electrical damage · job log · NTG-2025-1778
New Supply, Old Lead, Twelve Volts in the Wrong Place.
More power was what the new graphics card needed and the old supply did not have, so a wedding videographer on the edge of Gainsborough put a bigger unit into the edit machine. He kept the drive lead, which had been tied in there with the rest since the day I put this machine together
: it seated perfectly, and it looked identical to the one supplied in the box. He pressed the switch. A snap, and then that smell you get off hot electronics
. Three customers were still waiting for their films, and the 4TB WD Blue with the summer on it has been silent ever since.
Yours doing the same? Say what it is up to — looking is free.
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What went wrong, and why.
One end of a modular lead is nothing like the other. Where it meets the drive the pin order is published, so that half will do no damage whichever lead you care to use. Where it meets the power supply the arrangement is whatever the manufacturer decided: different across ranges, different again once a range is superseded, and with no marking on the outside of the plug to tell one scheme from another. So an old lead goes into a new unit, seats beautifully, and puts twelve volts onto pins that expect five. What the board does next is what it was built to do — the protection diode goes short-circuit, takes the rail down to earth, destroys itself doing it, and lets nothing at all through to the parts behind.
The bench work this one took.
How the work runs →| Kit on the bench | What it did on this job | Why we reach for it |
|---|---|---|
| ACE Lab PC-3000 Express | Confirmed nothing past the board had been affected, ahead of applying power | Reaches the maker's own service mode, which standard ATA commands cannot |
| PC-3000 Data Extractor | Took every sector as soon as the drive reported itself ready | Reads through the drive's own firmware and controller instead of working round them |
| R-Studio Technician | Pulled his folder tree out of the NTFS image and set it beside the booking diary | Rebuilds an array off the images, and reads almost any file system |
What happened on the bench.
How far the over-voltage actually reached
A microscope and a current-limited supply answered that inside ten minutes. One regulator destroyed, one protection diode shorted, heat marking around both of them, and past that, nothing. What ends a job in this category is the preamplifier — and the preamplifier lives on the head stack, inside the sealed body, which is precisely where those twelve volts never got.
A donor board, and one chip that has to travel
The right board revision was in stock, its own eight-pin ROM still soldered in place and left there. It was the chip from the failed board that moved. Tying a board to one specific drive is what that chip does: the values inside it were written from this head stack and these platters on the day the unit was assembled. A board without them will spin the drive, sound perfectly well, and give back rubbish.
Take the copy while it is still cooperating
Three customers were waiting, so the Data Extractor stood wired and ready before the replacement board came anywhere near the drive. Nothing had reached the mechanics. A rate that held level throughout, no new entries in the defect list, and a finished image by breakfast.
What was returned.
Undamaged edits, all three of them, straight off the image, and each film reached its couple on the day promised. The old supply's leads travelled back in the parcel as a single labelled bundle, taped together, so that none can find its way into a later build. A drive is published at £300 + VAT, and he had that figure in writing before any component was touched.
Start here if the same thing is happening to yours.
Other jobs that started with the power.
Sounds like yours? Switch it off before anything else.
£250 + VAT covers a card or a USB stick; a single drive is £300 + VAT; RAID and NAS start from £500 + VAT. Nothing is charged for the first look, and a fixed figure reaches you in writing before any chargeable work begins. Switch the device off, leave it alone, and post it in. On most jobs, no data back means no fee.