Data Recovery Case File · Electrical & Environmental Damage · A Known and Costly Mistake
Modular PSU Cables Are Not Interchangeable
His enquiry contained a suspicion and a red herring, and the suspicion is almost certainly right. "Two out of three drives I was moving between systems have failed — one hard drive and one SSD. I used a SATA power cable from the incorrect modular PSU and I am not sure if I fried them. An additional factor is that both drives are older than the one that is working, and were originally set up when the host machine was Windows 10; now both my machines are Windows 11." The operating system is not the explanation and can be set aside. The cable is, and it deserves to be stated plainly because this mistake is easy to make, looks harmless, and is one of the few things a person can do that destroys drives instantly.
| Media | One hard drive and one solid-state drive — both failed after connection using a modular power supply cable sourced from a different unit; a third drive on the same migration unaffected |
| Reported situation | Drives moved between systems · SATA power cable from an incorrect modular supply used · two of three drives failed · owner suspecting electrical damage · operating system difference also considered |
| Fault class | Over-voltage damage from mismatched modular cabling — drive electronics affected; recorded data and memory typically intact |
| Equipment used | Boards inspected under magnification with protection and regulation components assessed · component-level repair with original adaptive data preserved · vendor-mode access on the solid-state drive · imaging on restored access |
The decode: why the cables differ, and what the wrong one delivers
Why they look interchangeable and are not: a modular power supply has sockets on its body, and the cables plug into them. The device end of those cables is standardised — a SATA power connector is a SATA power connector, which is why the wrong cable fits a drive perfectly. The power-supply end is not standardised at all. Manufacturers choose their own pin assignments, and they differ between makers and frequently between models and generations from the same maker. So a cable that plugs into both units can be carrying entirely different voltages on the same pins.
What that does to a drive: a drive expects 12V on one line, 5V on another, and ground on the rest. Get the pinout wrong and the drive may receive 12V where it expects 5V, or a supply line where it expects ground. The 5V rail feeds the drive's logic — the controller and memory circuitry — and delivering more than double that destroys those components immediately, usually in the instant power is applied. There is no gradual damage and no warning; it is done before anything spins.
Why two failed and one did not: entirely consistent. Which connector on the cable each drive used, which drives were connected when power was first applied, and the differing tolerance of protection components between models all decide who survives. A drive with a protection device that sacrificed itself may be repairable; one without may have taken the damage straight to the controller. It is not evidence that the cable was innocent.
Why the operating system is a red herring: worth saying so he stops considering it. Windows version affects how a drive is used — filesystem features, drivers, encryption defaults. It has no bearing on whether a drive is detected by firmware, and a drive damaged electrically is not detected by anything regardless of what the machine runs.
Why the data is probably fine: the encouraging part. Over-voltage kills electronics, not recorded information. On the hard drive the platters and everything written on them are untouched, and board-level repair with the drive's own adaptive data preserved is the route. On the SSD the memory is normally unaffected while the controller or its regulation has failed, and vendor-mode access is attempted once the board can support operation.
What not to do now: connect either drive to anything until the boards are inspected. A damaged board may short its supply, and the drives should not be powered again casually — including on the machine that is working.
On the bench
Neither drive was powered on arrival. Both boards were inspected under magnification with the protection and regulation components assessed specifically, since over-voltage damage concentrates there and the pattern shows whether a protection device sacrificed itself or the damage reached the controller. The hard drive's board was repaired at component level with its original adaptive data preserved, rather than substituted, so the drive read its own surfaces correctly. On the solid-state drive, access was attempted through the PC-3000 portfolio's vendor technological modes once the board could support operation. Both were imaged on restored access and verified by opening.
The outcome
Both boards assessed and repaired at component level, access restored and the contents imaged and verified. Free assessment, one fixed written figure including VAT, 50% of parts and labour upfront with the balance only on successful recovery. The decode, for anyone who has swapped modular power cables: the device end is standardised and the power-supply end is not, so a cable that physically fits both units can carry different voltages on the same pins — which means the wrong cable can put 12V onto the 5V line feeding a drive's logic and destroy it the instant power is applied; two drives failing and one surviving is consistent with that rather than evidence against it; the operating system is irrelevant, because a damaged drive is not detected by anything; and the data is normally intact, because over-voltage kills electronics rather than recorded information.
Used a power cable from a different modular supply
Stop powering the drives, and treat your suspicion as almost certainly correct. Modular power supply cables are standardised at the drive end and not at the power supply end — manufacturers choose their own pin assignments, which differ between makers and even between models from the same maker. So a cable that plugs happily into both units can deliver 12V where the drive expects 5V, and that destroys the drive's logic in the instant power is applied. It's one of the very few mistakes that kills hardware immediately rather than gradually. Two drives failing and one surviving is normal for this, depending on which connector each used and what protection components they carried. Don't test them further, don't try them in the working machine, and set aside the Windows version question — an operating system can't prevent a drive being detected by firmware.
Don't power them again — call Glasgow Data Recovery on 0141 404 0294; boards inspected at component level, repaired with original adaptive data preserved, imaged on restored access.
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Our case files are drawn from genuine enquiries received by our laboratory over the past ten years, anonymised to protect client confidentiality. Each one describes the diagnostic and recovery procedure our engineers apply to that fault, using the equipment listed.