Modification to improve reliability of the PNA SATA Hard Disk Drive.
Applicable to all PNAs that use SATA drives except for the PNA-X models (N524xA and N5264A.)
Most of the affected instruments are the PNA C models, however replacement drives may also be affected.
Some hard drive trays used in PNAs shipped between June 2009 and December 2009 were improperly made. This also includes trays used for replacement purposes for the E836xA/B and N5230A models. This could include drive models N8980A, N8981A, N8982A and part numbers E8801-60070, E8364-60192, and N5230-60050. The PNA-X family is not affected.
It is possible that the center of the X frame of the tray is slightly bowed upwards which will cause the hard drive to warp when screwed down. If the drive is warped, a head crash may occur which will destroy the drive and all data. Only SATA (Serial ATA) drives are affected; PATA drives do not have this issue. SATA drives are identifiable because they use a flat X-shaped Mylar insulator between the drive and the tray; see picture below. Agilent will replace any drive that fails due to this issue but it is better to perform a simple modification that will prevent this in the first place. Also check any drives that may be used as spares.
Checking the drive
A drive tray is okay if a strip of paper can be inserted between the HDD and the center of the X-frame as shown below. Any clearance other than zero is acceptable. If there is no clearance between the center of the X frame and the drive (or Mylar sheet) then perform the simple modification below.
Modifying the tray
To modify the tray, you will need two insulating washers that will fit an M3 screw (or English #6.) The washer should be about 1mm (~3/64") thick and no more than 1.5mm thick. Most any type of insulating washer will suffice; fiber, neoprene, plastic, etc. Remember, the goal is simply to allow some clearance at the center of the X.
For Agilent factory use: The Agilent part number for the washer used in the factory is 0340-1525. However, because this is a shoulder washer, you will need 4 washers for each tray modification; one on top and one on the bottom of the frame for each side. The existing two shoulder washers (shown in red below) will have to be replaced with the two newer (shorter) versions.
Note: Do not add any washers to the front screws, near the PC board!
- Slightly loosen (by 1 or 2 turns) the two screws near the front of the drive where it connects to the PC board
- Remove the two screws (with nylon insulator) at the rear of the drive
- Insert a fiber washer between the tray frame and the drive for each screw. While not critical, the washer should be above the Mylar insulator as shown below
- Replace the two screws with the nylon insulator
- Tighten the two front screws
- Verify that there is now some clearance at the center of the X frame
Last Updated: Jan 6, 2010