CAUT ION
8.28 DRIVE MOTOR AND PULLEY REMOVAL
1. Place CB1 to OFF.
2. Unlatch and open rear gate.
3. Unclip terminals attaching two wires to pack-on switch.
4. Remove motor tension spring to motor tension plate.
5. Rotate motor clockwise enough to allow drive belt to be slipped up and off drive motor pulley.
6. Remove belt by dropping one side of it between pack-on switch and drive motor.
INSTALLATION
Replace drive belt by reversing removal procedure.
8.28 DRIVE MOTOR AND PULLEY REMOVAL
1. Perform all steps for removal of drive motor belt.
2. Remove sequence panel cover by pulling out plunger fasteners and lifting off cover.
3. Disconnect motor cable wires to SP1 and to sequence panel chassis.
4. Remove nut that fastens drive motor cable to sequence panel and pull cable out of sequence panel.
5. Remove one bolt (to rear and right-hand side of motor) that holds motor mounting palte to bottom of baseplate.
6. Rotate drive motor clockwise to disengage motor mount from rear bolt, and, then, move motor to rear to disengage motor mounting plate from front bolt.
7. If drive motor is to be replaced, perform additional steps. (Omit these steps if pulley is being replaced.)
a. Separate drive motor from mounting plate (four bolts and washers).
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b. Unscrew four shock mounts and adapters from drive motor.c. Save these parts for use with replacement motor.
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8. Remove pulley from motor shaft as follows:
a. Loosen three screws that secure pulley clamp to motor shaft.
b. Remove pulley with puller.
INSTALLATION
1. Replace pulley as follows:
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a. Place key in slot in motor shalt.
b. Use hard rubber or plastic mallet and tap pulley onto motor shaft.
2. Fasten pulley to pulley clamp.
3. If four shock mounts and adapters were removed (as when the motor is being replaced), screw these onto drive motor housing.
4. Fasten mounting plate (if previously removed) to drive motor.
5. Measure distance from top of pulley to bottom of mounting plate. This distance must be 0.176 ± 0. 010 inch. If necessary, adjust as follows:
a. Loosen setscrew on pulley clamp.
b. Tap motor pulley assembly in appropriate direction to obtain proper distance.
c. Retighten pulley clamp setscrew.
6. Complete replacement by reversing steps 1 through 6 of removal
proce-dure.
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8.29 BLOWER PLENUM ASSEMBLY (Figure 8-1) REMOVAL
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1. Place CB1 to OFF.
2. Remove front cover.
3. Disconnect blower cable from power source. [1
4. Loosen clamp securing blower exit duct to blower plenum and slide off duct.
5. While supporting blower and plenum by hand, remove filter-locking rod (at top of plenum) that attaches blower plenum to inlet filter duct.
6. Lift blower plenum assembly up and out, disengaging plenum ears from slots in air system support plate.
INSTALLATION
1. Before replacing blower plenum assembly, be sure that arrow on abso lute filter housing is pointing in direction of air flow.
2. Replace blower plenum assembly by reversing removal procedure.
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8.30 INLET FILTER DUCT (Figure 8-2) REMOVAL
1. Perform all steps in removal procedure for blower plenum assembly.
2. Lift absolute filter off air support plate.
3. Unlatch and open PWA gate.
4. Extract three screws that fasten inlet filter duct to air system support plate and lift off inlet filter duct.
INSTALLATION
1. Place inlet filter duct on air system support plate and fasten with three screws.
2. Place absolute filter on air system support plate with arrow on filter housing pointing in direction of air flow.
3. Perform reversal of removal procedure for blower plenum assembly.
8.31 AIR SYSTEM SUPPORT PLATE AND SUPPORTED UNITS (Figure 8-1) REMOVAL
1. Place CBlto OFF.
2. Disconnect blower cable from power source.
3. Unlatch and open PWA gate.
4. Remove screw securing air system support plate to standoff on power supply plate.
5. Remove seven screws and washers fastening air system support plate to disk drive frame. Lift out air system support plate and attached units.
INSTALLATION
Replace air system support plate by reversing removal procedure.
8.32 SPINDLE HOLDING PAWL (Figure 8-6) REMOVAL
1. Place CB1 to OFF.
2. Remove top cover assembly, front cover, shroud, right-hand side cover, blower plenum assembly, and absolute filter.
3. Remove retaining ring securing lever coupler to pivot shaft and disconnect.
4. Remove socket-head screw, flat washer, and spring which hold spindle holding pawl to baseplate.
5. Remove spindle holding pawl (with link rod attached) and nylon washer between pawl and baseplate.
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6. To disassemble spindle holding pawl assembly, remove retaining ring from brake actuating link. Extract link from pawl. Pawl return compres sion spring and second retaining ring on link are also freed by this action.
INSTALLATION
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1. Replace spindle holding pawl by reversing removal procedure.
2. Check and adjust spindle holding pawl according to paragraph 6. 10.
8.33 PACK-ON SWITCH ASSEMBLY (Figure 8-5) REMOVAL
1. Place CB1 to OFF.
2. Remove front cover.
3. Unclip terminals on two wires to pack-on switch.
4. Remove two screws fastening pack-on switch assembly by reversing re moval procedure.
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INSTALLATION
Replace pack-on switch assembly by reversing removal procedures.
8.34 SPINDLE GROUNDING CONTACT (Figure 8-6)
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REMOVAL
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1. Place CB1 to OFF.
2. Remove one of the two screws securing pack-on switch bracket to base-plate and loosen other screw.
3. Rotate pack-on switch to provide clearance to grounding contact.
4. Pry off nylon contact retainer. Grounding contact will stay in retainer and may be removed with fingers.
INSTALLATION
1. Replace spindle grounding contacts by reversing removal procedure.
2. Check and adjust pack-on switch according to paragraph 6.9.
8.35 SPINDLE ASSEMBLY (Figure 8-1)
REMOVAL
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1. Place CB1 to OFF.
2. Remove top cover assembly and front cover.
3. Perform the following steps to facilitate removal of spindle holding pawl and drive motor belt.
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a. Loosen clamp on blower exit duct, and slide clamp up duct. Dis engage blower exit from blower plenum.
b. Remove screws from shroud inlet duct, and lift it and the blower exit duct from baseplate.
4. Remove spindle holding pawl and drive motor belt.
5. Extract three socket-head screws securing spindle to baseplate.
CAUTION
Use extra care when removing spindle from baseplate to prevent binding.
Spindle must be lifted straight up and must not be tilted.
6. Lift spindle straight up and away from baseplate.
INSTALLATION
1. With 90% ispropyl alcohol, clean spindle and baseplate surface that con tacts spindle. Use lint—free tissue.
REMOVAL
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CAUTION
In performing step 2, do not tilt spindle when lowering into baseplate. Otherwise, binding may occur.
2. Lower spindle into baseplate, slowly and carefully to ensure proper alignment and to prevent binding.
3. Complete replacement by reversing steps 1 through 5 of removal pro cedure.
4, Perform read/write head check and adjustment procedure according to paragraph 6. 7.
8.36 ELECTRONIC (PWA) GATE ASSEMBLY (Figure 8-2)
1. Place CB1 to OFF.
2. Open PWA gate.
3. Release PWA gate card latch.
4. Cut cable ties securing cables to gate frame.
5. Extract paddle PWA’s.
6. Disconnect ground strap attached to bottom of baseplate (by screw and lockwasher).
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7. Unsolder wires from DC power supply connected to voltage terminals
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underneath PWA gate behind front panel.
8. Unsolder Read coax and ground wires from PWA 5 connector, pins 5 and 6.
9. Unsolder Write coax and ground wires from PWA 4 connector, pins 33 and 2.
10. Remove screw, washer, and nut gate stay to bracket on drive frame.
11. Support gate assembly so it will not fall and remove two screws securing gate hinge to hinge bracket on drive frame. Lift off PWA gate assembly.
INSTALLATION
Replace PWA gate assembly by reversing removal procedure.
8.37 RESISTOR BRACKET ASSEMBLY (Figure 8-1) REMOVAL
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1. Place CB1 to OFF.
2. Remove front cover and top cover assembly.
3. Remove EMA cover.
4. Disconnect two wires from EMA coil (two screws and nylon washers).
5. Disconnect clamp securing EMA coil wires to EMA frame and ties holding them to other wire harness.
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6. Disconnect wires from resistor bracket assembly to power driver termi- / nal board PD1 according to following table.
Resistor Bracket Power Driver
Component/Te rminal PD1 Terminal
R13-1 14
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R13—2 7
R15—l 15
1
R14-2 6
Li—i 16
7. Remove appropriate cable ties so wires disconnected from power driver PU1 may be removed.
8. Remove two screws that secure resistor bracket assembly to frame, and
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lift out assembly (including attached wires). 0
INSTALLATION
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U Replace resistor bracket assembly by reversing removal procedure, except perform -‘
step Z after all wires have been reconnected.
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8.38 POWER DRIVER ASSEMBLY (Figures 8-2 and 8-3) REMOVAL
1. Place CB1 to OFF.
2. Remove front and rear covers.
3. Remove power driver cover (four screws and lockwashers).
4. Disconnect all wires at input terminals of PD1.
5. Supporting power driver to prevent its falling over, remove five screws securing power driver to sequence panel.
INSTALLATION
Replace power driver by reversing removal procedure.
REMOVAL AND REPLACEMENT OF POWER DRIVER PWA
1. Perform steps 1 through 3 of power driver assembly removal.
2. Unsolder at PWA wires that connect to external destinations.
3. Remove four screws fastening PWA to standoffs on power driver support, and lift off PWA.
8.39 POWER SUPPLY ASSEMBLY (Figure 8-1) REMOVAL
1. Place CB1 to OFF.
2. Remove front cover.
3. Remove long standoff that supports air system support plate. This stand off is located at rear of regulator assembly.
4. Disconnect two wires from power driver and one wire from DC in connec tor to power supply capacitor Cl (two screws). Reconnect other wires that connect to Cl to other power supply components.
5. Remove PSi terminal board cover (three screws), and disconnect all wires that connect PSi and adjacent ground bar to external connections.
6. Disconnect all wires that connect PS2 to units external to power supply.
7. Disconnect all wires that connect PS3 to units external to power supply.
8. Remove two screws that secure clamps, and also, in part, secure power supply mounting plate to disk drive frame.
9. Remove remaining six screws and lockwashers that secure power supply mounting plate to disk drive frame.
10. Lift out power supply assembly toward front of disk drive.
INSTALLATION
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Replace power supply assembly by reversing removal procedure.2341—2
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