PCC D3400 - Scale Assembly Removal and Installation; Scale Assembly Removal

6.24.2 RETICLE INSTALLATION
The reticle is an integral part of the Sensor Receiver Assembly and is installed in the drive
in accordance with the following procedure.
(1) Insert leads 1 through 5,9,10, and 12 with their pins o~ the replacement Sensor
Receiver Assembly into the mating pin holes in
plug J203 and reinstall onto the
Servo PCBA.
(2) With the reticle arm pOinting toward the rear of the disk drive, insert the sensor
receiver post into the hole provided
in the thermal compensation block.
(3) Rotate the Sensor Receiver Assembly counterclockwise until the reticle is directly
under the
scale. If this cannot be done, adjust the Allen head screw inside the
sensor receiver
assembly post so that the bottom of the Allen head screw is
flush with the bottom of the post.
CAUTION
WHEN ROTA TlNG THE SENSOR RECEIVER ASSEMBL Y,
ENSURE THE RETICLE DOES NOT CONTACT ANY PART
OF THE SCALE ASSEMBL Y.
(4) Tighten the hexagonal Allen head screw on the temperature compensation block
until
it is just possible to rotate the post.
(5) Adjust the Allen head screw inside the sensor receiver post so that the clearance
between reticle and the scale is 0.005 inches. A 0.OO5-inch mylar shim can be
used for this purpose.
(6) Replace the Lamp/Lens Assembly according to the procedure detailed in
Paragraph 6.23.2.
(7) Replace the tie wraps removed in Paragraph 6.24.1, Step (4).
(8) Perform the positioner servo calibration procedures in Paragraphs 6.7 through
6.9.
6.25
SCALE ASSEMBLY REMOVAL AND INSTALLATION
Removal
of the Scale Assembly is occasioned by mechanical damage to the scale frame,
or in the event that the
glass scale is cracked or broken.
6.25.1 SCALE ASSEM BL Y REMOVAL
(1) Remove the top two magnetic heads by following head removal procedure
detailed in Paragraph 6.22.1.
(2) Remove the Lamp/Lens Assembly by following the procedure detailed in
Paragraph 6.23.1,
Steps (1) and (2).
(3) Remove the three Allen head screws that hold the Scale Assembly to the carriage.
The Scale Assembly will still be held in place by the locating pin on the carriage.
(4) Remove the Scale Assembly by carefully applying sufficient pressure to
disengage
it from the locating pin.
CAUTION
WHEN REMOVING THE SCALE ASSEMBLY, ENSURE
THAT IT DOES NOT CONTACT THE RETICLE. DO NOT
TOUCH ANY PORTION OF THE GLASS SCALE.
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