ST31000528AS head-assemlby platter removal

Head-assembly swap: Seagate ST31000528AS

In Blog, Hard Disk Drive Recovery Case Study, Recovery of the day by Administrator

21/2/2019 – Seagate 1000GB 7200.12 Barracuda

A desktop HDD provided by an IT Support company on behalf of their customer. The HDD was making a distinctive clicking sound. Quickly it was possible to establish that the HDD has a failure of the read-write heads. To attempt to recover data it would be necessary to replace the failed head assembly. This is a ‘mechanical failure’ for the purposes of pricing.

Hard disk drive details:

  • Manufacturer: Seagate
  • Model: ST31000528AS
  • PN: 9YP154-521 .
  • SN: 9VP…
  • Firmware: JC4A
  • Site Code: TK
  • Printed Circuit Board: 100535537 REV A


Use of a matching donor HDD was required. Seagate 7200.12 series HDDs have a head-assembly which parks on the platter surface when powered off. This means that the read-write heads make contact with a demagnetised area of the platter near the spindle motor. This means that it is necessary to retract the head-assembly off the platter surface for replacement. For this, we use specialist tools manufactured by HDDSurgery. The particular tool used allows for the removal of the head-assembly without causing the read-write heads (sliders) to make contact with the area of the platter where data is stored. This minimises the chances of damage to either the read-write heads or the platter.

This method of head-assembly removal is preferred and is the choice of professional data recovery services. Attempts to ‘drag’ the head assembly across the platter to mount on plastic head-combs should be avoided, as there is a greater likelihood of damage to occur, and consequently a lower chance of a successful recovery.

Once the head-assembly was replaced in the failed HDD, it was necessary to import the ‘head adaptives’ from the ROM code. At this stage, the HDD would only partially calibrate. It was necessary to read the firmware via the terminal connection and then make appropriate alterations, including clearing of the G-List.

Once completed it was possible to start reading the data within PC3000 Data Extractor. A full recovery of the critical data was possible.

Detailed technical information for data recovery professionals:

HDD: Pharaoh
Product FamilyId: 3F, MemberId: 03
PreampType: 71 03
Servo FW Rev: B780

  • It was necessary to import head-adaptives.
  • The HDD would click when powered on but after two minutes would reach ‘RDY’.
  • F3 T> access was available.
  • Any ATA command would result in the HDD entering BSY.
  • Critical SYS files were read via terminal.
  • There were read errors in the SMART sys files, and faults with the G-List / Alt-List.
  • It was necessary to clear SMART and Alt-list via terminal commands.
  • After this direct access via ATA was possible.
  • The disk would still occasionally making ‘clicking’ sounds, but when imaged in Data Extractor read very well with few errors.

Error messages in the terminal log:

Rst 0x20M
RW: Disc Ctlr Initialization Completed.
(P) SATA Reset

RW: Error processing Performance Parameter File: 203C
Rst 0x20M
RW: Disc Ctlr Initialization Completed.
(P) SATA Reset

RW: Error processing Performance Parameter File: 203C
Starting LBA of RW Request=05B2C270 Length=FFFFFFFF