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PDR / Everyday faults / Drives no computer will see

The symptom · nothing shows up

Drive not detected in Plymouth. Invisible, not wiped.

All drives received from across Plymouth, Devon and Cornwall have one thing in common: when you try to access them on your computer, they don't appear. That describes a circuit, and gives you no clue as to what is in the files. In order to identify what may be wrong with your drive, answer these three questions in sequence. Can you see it listed in the BIOS? Does it show up in Disk Management? Can you open it in File Explorer? The place the drive stops helps show which component is damaged: the electronics, the firmware or the volume.

Nothing readable? Most jobs carry no bill Free diagnosis, then one written price Boxes come to the lab from Truro, Newquay and Tavistock

You will be talking to an engineer
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Drive not detected: what each symptom points to.

Yours not here? Start at the triage →
The behaviourWhat that points toWhere to start
Disk Management shows Unknown, Not InitializedIt responds, but with no valid signature, and nothing of the partition table remainsAnswer no to that box
The message that ends with “…before Logical Disk Manager can access it”Agree, and an empty partition map replaces everythingDecline it, then unplug
Disk Management reports No MediaOnly the controller responds; the storage behind it is out of reach. This is a hardware issue, not a logical one.Keep it disconnected
The BIOS has no entryA burnt circuit board, a protection diode that has shorted, or a service area that will not load: electronics or firmwareRepair at component level
A 1TB disk listed as 8MB by the BIOSDamaged firmware or translator, which makes the reported size meaninglessFirmware tools are needed, not software
Power goes in, nothing happensBurnt-out electronics, and the TVS diode has shortedUsually readable
Shipping to us: once you receive your quote, pack it securely so it won't move in transit, get it insured for what it is worth, and send it by tracked post to our intake lab in Bristol. We pay the postage back to you. Please contact us before sending if you would like an engineer to check the packing before the box is sealed. More detailed instructions on sending your item to us can be found on our contact page.

Identify the fault by breaking it all down a little bit at a time.

Nothing in the BIOSAt the lowest (bottom) rung, you are looking at an electronic or firmware issue, such as burnt tracks, a shorted diode or service-area code the drive will not load. Most often the platters are unharmed.
In the BIOS, absent from Disk ManagementThe drive is responding properly. The problem sits at a higher level: the partition table, or the file system's internal bookkeeping. Both are fixed on the image, not on the disk.
Absent from Explorer aloneEverything underneath is functioning correctly, but the volume still won't mount. This means there is something wrong with the file system, and since this kind of work typically runs without issues, it should be relatively easy to resolve.
Nowhere at allTypically with a hard disk, this type of issue occurs because of a power surge that causes the TVS diode on the supply rail to short-circuit. Simply replacing the board will not fix the problem, because the disk calibration data is stored within the ROM chip on the damaged board. Therefore, the ROM chip must be desoldered and transferred to the new board.

What happens to a drive while it is here.

Cases in the log →
01

A number on arrival, then the free diagnosis Free

Whatever is delivered is booked in using a unique reference (case number) on the date it arrives at the bench. The engineer will identify the actual fault at no charge. This gives a straightforward answer on what can be recovered from the drive and what cannot, plus one written quotation. There will be no further activity until you have read and accepted the quotation.

Diagnosis at no chargeA single written figureYou owe nothing yet
02

Which stage it stops at

Nothing is taken apart, and nothing is left running. A simple look at the BIOS, Disk Management and Explorer will tell you which of three possible repairs is needed: repairing the electronics, rebuilding a service area, or repairing the file system on a duplicate.

Tested in sequenceYour disk is never written to
03

Mending the electronics

The shorted diode is removed and replaced. If the board cannot be repaired, a donor board is used and your original ROM chip is moved onto it. The adaptive values on your original ROM chip were taken from your own platters and would not match any other disk.

Donor board, your own ROMShorted diodes renewed
04

Image it, then work on the image

Once the drive responds, a sector-by-sector image of it is made. From then on all work happens on that image, and your own drive is put away on a shelf, untouched.

A full sector imageThe drive itself untouched
05

You give the word, and it ships back

Give yourself time to consider it. It costs you nothing. We list all of the files we recover for you before sending out an invoice, and we only ask for payment once you have authorised it. We also buy media specifically for your recovery and send it back to you, with the return postage paid by us. The case stays here on our bench until we have your confirmation that the files open properly on your own machine.

You see the list and decideWritten to fresh mediaWe pay the postage home

The faults we see most

  • Each of these stages describes a different part of the system: a drive can fail at the BIOS level, it can be present in Disk Management but make no further progress, or it can show in Explorer but still fail to mount. Determining which of these happened makes up most of the diagnostic process.
  • The TVS diode is actually designed to fail: it shorts the rail and absorbs the voltage spike. As a result, a drive that appears dead usually has platters that are healthy.
  • Matching model numbers do not mean matching boards: calibration information for a specific set of platters sits on the ROM chip found on the original printed circuit board (PCB). So even though a donor PCB may match the original model number, it carries calibration for another person's platters.
  • Flash is different: a bad controller or panicked firmware can create a barrier between you and NAND that is perfectly good. WD Blue SA510 drives that report 0MB are the typical case. There is a separate page about SSDs.

The point worth keeping: nearly all the drives we receive that are invisible to their computers have a fault in their electronics or firmware. Those are the parts that tell your computer the disk is there. They are not the parts storing your data. A drive that is not recognised is telling you about its own hardware, and nothing beyond that.

A job out of the casebook.

PL · PLY-2026-0618FILED ✓

A shorted TVS diode, and the WD wouldn't spin

A power cut during the night, and in the morning the desktop showed only one disk instead of two. The WD would not spin at all, and there was no BIOS entry for it. The board had failed at the TVS diode. Its ROM chip was fitted to a donor PCB and a full image came off two days after the parcel reached us.

100% imaged2 days start to finish

Before you seal the box.

Get these done

  • Swap the cable and the port, then stop there
  • Tell us if you can hear or feel it turning
  • Mention any power cut, surge or lightning
  • Send it exactly as it stands, unopened

What to avoid

  • Agreeing to the Initialize Disk prompt
  • Fitting an identical board and leaving the ROM behind
  • Trying it in every computer you own
  • Buying a donor board and soldering at the kitchen table

Questions that come up most weeks.

It does nothing at all. Is anything recoverable?

Yes, generally; whether the board is repaired or replaced, the damage rarely gets beyond the electronics to the platters or flash. Dead drives are among the more predictable failures that we see on this bench.

It is asking me to initialise the disk. Should I accept?

No, never. That box will write an empty partition map over the top of the map showing where your files are. Say no and pull the cable off the drive. Have an engineer look at it before doing anything else to it.

Nothing is shown in the BIOS. Does that mean it's done for?

No. A disk that is missing from the BIOS has simply lost its ability to identify itself, not its data. The failure is in the electronics or in the code that lives in the service area, and your data is in neither of these places.

There was a power cut and it died. Connected?

Very probably. Protection diodes absorb spikes: they are put there to short out and fail first, before anything further in can be affected. What you've lost is electronics. Your files remain unaffected.

A drive that stays switched off gets no worse.

Diagnosis costs nothing. We give you a report listing which files can be read, which cannot, and what is needed to get them off. Do not connect the drive until then.

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