HGST HDS724040ALE640

HGST HDS724040ALE640 3.5″ hard drive with a storage capacity of 4 TB and featuring a SATA interface. HGST HDS724040ALE640 Deskstar 7K4000 4 TB 3.5″ Internal Hard Drive Serial ATA-600 7200 RPM 64 MB Buffer.

All information about the HGST HDS724040ALE640 hard disk drive: technical parameters, failure symptoms, frequently asked questions, reviews, HDD repair and data recovery.

HGST HDS724040ALE640 Technical Details:

Manufacturer:

HGST (Hitachi Global Storage Technologies)

Hard Disk Model:

HDS724040ALE640

Disk Family:

Deskstar 7K4000 (Performance series)

Form Factor:

3.5″

Capacity:

4 TB (4,000,000,000,000 bytes)

Formatted Capacity:

Approximately 3.63 TB

Number Of Disks:

Number Of Heads:

Rotational Speed:

7200 RPM

Average Seek Time:

8.5 ms (read) / 9.5 ms (write)

Disk Interface:

Serial ATA-600 (SATA 6 Gb/s)

Buffer Size:

65536 KB (64 MB)

External Transfer Rate:

600 MB/s

Internal Transfer Rate:

Up to 205 MB/s

Mean Time Between Failures (MTBF):

1,000,000 hours

Advanced Format:

512e (512-byte emulation, 4K physical sectors)

Note: The HGST HDS724040ALE640 is part of the Deskstar 7K4000 series, released around 2012-2013. This was HGST’s flagship high-performance consumer drive, offering 4 TB of storage at 7200 RPM. The 7K4000 series featured 4 platters and 8 heads, delivering excellent capacity and performance. It was one of the first 4 TB consumer drives on the market and became a favorite among NAS and RAID users.

HGST HDS724040ALE640 Hard Drives:

HDS724040ALE640 – 4 TB SATA 3.5″ Performance Hard Drive, Deskstar 7K4000 series
Model code breakdown: HDS72 (Deskstar 7K4000 series) + 4040 (4 TB capacity) + ALE640 (SATA 6Gb/s, 64 MB cache)
Common firmware revisions: 5C0, 5C1, 5E0, 5F0, M5A0
Capacity in LBA: 7,814,037,168 sectors
Also known as: Hitachi HDS724040ALE640 (pre-acquisition branding)
Recommended usage: High-capacity desktop, NAS, RAID, media servers

HGST HDS724040ALE640 Failure Symptoms:

Electrical Failure Symptoms:

Drive is powered, but shows no sign of function;
Disk knocking as the motor fails to spin;
Clicking sound as the heads search or initialize;
Burnt components on PCB.

Mechanical Failure Symptoms:

Clicking, grinding sounds;
Completely quiet due to “motor freeze”;
Drive spins but produces rhythmic clicking – typical of head failure;
Occasional “scraping” sound.

Logical Failure Examples:

Accidental deletion, accidental format, file corruption;
File system corruption, viruses and malware;
Partition table loss or MBR/GPT corruption.

Firmware Failure Symptoms:

Drive powers up but is not recognised;
Drive recognised wrongly with nonsensical characters;
Drive freezes during booting up;
Drive detected with 0 MB capacity.

Bad Platter Area Symptoms:

Hard disk appears to “hang” or be “sluggish”;
Constant Cyclic Redundancy Check (CRC) errors;
Unable to access folders or files;
Gradual increase of reallocated sector count.

Complex Failure Model

(A combination of two or more of the above failure types)

HGST HDS724040ALE640 Data Recovery & HDD Repair:

Common problems for the HDS724040ALE640 include PCB failure, firmware corruption, and head failure.

PCB Replacement Information:

To replace a faulty PCB, match the following:

Model number: HDS724040ALE640
PCB part number: Common numbers include 0A90020, 0A90021, 0A90720
Main controller IC number: Often 88i9346 (Marvell)
Firmware revision: e.g., 5C0, 5C1, 5E0

⚠️ Critical Note: You MUST transfer the original ROM chip from the old PCB to the new donor board. Without this, the drive will not function correctly.

Symptom Analysis:

Symptom

Likely Cause

Recommended Action

Drive dead (no spin)

PCB failure

Replace PCB; transfer ROM chip

Spins but not detected

Firmware corruption

Professional repair with PC-3000 or MRT

Rhythmic clicking

Head failure

Cleanroom head swap required

Extremely slow access

Bad sectors

Disk imaging with ddrescue

Repair Options by Failure Type:

Failure Type

Solution

Requirements

Burnt PCB

Replace PCB; transfer ROM chip

Donor board + soldering/programmer

Firmware corruption

Professional repair

PC-3000 or MRT

Head failure

Head/platter swap

Cleanroom + donor drive

Bad sectors

Disk imaging

ddrescue or PC-3000

Logical failure

Software recovery

TestDisk / R-Studio

Frequently Asked Questions (FAQs):

Q: What is the capacity of the HDS724040ALE640?
A: 4 TB (approximately 3.63 TB formatted).

Q: What is the RPM and cache?
A: 7200 RPM and 64 MB cache.

Q: Is this drive good for NAS?
A: Yes, the 7K4000 series was popular for NAS and RAID use. However, ensure your NAS supports 4 TB drives.

Q: What are the 4 TB compatibility issues?
A: 4 TB drives require:
– UEFI BIOS (not legacy BIOS)
– 64-bit operating system
– GPT partition table

Q: Is this drive worth buying today?
A: For legacy system repair, yes. For new builds, modern drives (6TB-20TB) offer better value.

User Reviews & Summary:

Pros:
– 4 TB high capacity for its era
– 7200 RPM performance
– 64 MB cache
– 1 million hour MTBF
– Excellent for NAS and RAID
– Highly reliable

Cons:
– 4 TB may have compatibility issues on older systems
– Discontinued – used only
– 4 platters, 8 heads – more potential failure points

Final Verdict:
The HGST HDS724040ALE640 (Deskstar 7K4000, 4 TB) was a groundbreaking high-capacity performance drive. While now obsolete for primary storage, it remains a solid choice for legacy NAS systems.

Pro Data Recovery Tip: The 7K4000 series is generally reliable, but as with all mechanical drives, monitor SMART attributes regularly, especially 05 (Reallocated Sectors) and C5 (Pending Sectors).