<f KIT PIN 215970 AVAIL LlGN HD
FIGURE 4-4. CLEANING HEADS OUT OF DRIVE
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4.6.2 Head Rel)lacement
4.6.2.1 Tools Required
Tools required are the Head Installation Tool (PIN 210105), Head Torque Tool (PIN 210109), and Torque Tool Shaft (PIN 211526).
Torque Tool Shaft has a press··fitted Allen tip. The shaft slides into the opening at either end of the torque tool itself, one end of which is calibrated to provide an INITIAL torque and the other end a FINAL torque. The words INITIAL and FINAL are etched onto the tool itself.
4.6.2.2 Removing a Head 1. Remove pack.
2. Slide logic gate 'forward by mleasing both latches at the rear of the gate and pushing with equal forGe on each side (don't twist the gate as it slides).
3. Release the leaf-spring latch on the bottom right side of the wind tunnel, and slide the wind tunnel to the rear.
T-BLOCK ALIGNMENT HOLE IN
~\
HEAD/ARM ASSE:MBL Y ~ e
~~~''''''''''''';:~s<.l.II-'''I\) ~ ~~~
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/ ALIGNMENT CLIP\ FORWARD ALIGNMENT CLIP SCREW REAR ALIGNMENT CLIP SCREW
FIGURE 4-5. HEAD ALIGNMENT CLIP AND SCREWS 677 -01/51.20-00-12/75
4. Remove the clamps on each side of Gam tower that hold the head plu'gs in place by pressing down on the leaf spring at the top and pulling back.
5. Disconnect head plug.
6. Referring to Figure 4-5, remove the two alignment clip screws and tl1e alignment clip which hold the head assembly in the T-block slot.
7. Determine whether the head is an 'A' or 'B' type head by referring to Figure 4-6.
8. Grip head assembly with Head Installation Tool, as indicated in Figure 4-7 ('A' type head) or Figure 4-8 ('B' type head).
9. Close jaws of installation tool completely and remove head assembly from drive. Do not touch the slider face or press against the flexure (slee Figure 4-8). Even slight pressure against the flexure could bend it;
excessive pressure will damage the head's pitch and roll attitude adjustments.
0
A DOWN 2
B UP 4 B DOWN 3
4
16 6
A DOWN A UP 5
B UP 8 B DOWN 7 8
(SERVO) A DOWN 10 A UP 10 19
B UP 12 9
B DOWN 12
14 14
A DOWN A UP 11
B UP 16 B DOWN 13
16
A DOWN 18 A UP 18
15
B UP 17
COVER DISC
FIGURE 4-6. T-BLOCK, VIEWED FROM LINEAR MOTOR
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4.6.2.3 Installing a Head
1. Remove the alignment clip screws and the alignment clip from the head assembly being installed.
NOTE
Replacement head assemblies supplied to DEC contain alignment hardware (alignment clip and screws).
2. After reading the notes below, install the head into the drive.
a. An 'A' or 'B' type head assembly must be installed into an appropriate position (see Figure 4-6).
b. A head assembly must be installed into its rearmost position in the T-block slot.
c. To hold a head assembly, grip it with the Head Installation Tool as indicated in Figure 4-7 ('A' type head) or Figure 4-8 ('B' type head).
d. To place a head assembly into the drive, close jaws of installation tool completely and insert into rearmost position in T-block slot.
Don't pinch the pigtail wire with the tool. Do not touch the slider face or press against the flexure. Even slight pressure against the flexure could bend it; excessive pressure will change its setting.
'A' TYPE HEAD
FIGURE 4-7. HEAD INSTALLATION TOOL IN 'A' TYPE HEAD 677-01/51.20-00-12/75
e. Before torquing the screws (see Figure 4-9), check to see that the arm is resting properly on the cam surface and that the flexure has not been bent during head installation. This can most easily be observed from the front of the machine.
f. When installing several head assemblies, both screws should be torqued to INITIAL torque using the Head Torque Tool. (Servo head is always torqued to FINAL torque.) Begin at the bottom of the T-block and proceed to the top, one side at a time, leaving all head plugs disconnected. Be sure to install servo head screws guard after FINAL torque; failure to do so may prevent proper alignment of the read/write head assemblies.
3. With all alignment screws torqued to INITIAL torque, except servo which is torqued at FINAL torque, connect read/write head plugs to matrix PCBs. Connect servo head plug to matrix PCB and servo preamp.
4. Replace the head plug clamps, being sure that the tabs on the leaf springs are fully seated into the cam tower holes.
5. Check for HOI after purging system 5 minutes by performing a manual head load.
6. Perform the head alignment procedure in paragraph 4.6.3.
'8' TYPE HEAD
FIGURE 4-8. HEAD INSTALLATION TOOL IN '8' TYPE HEAD
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FIGURE 4-9. USING HEAD TORQUE TOOL
4.6.3 Head Adjustment
The procedure for head adjustment in the system environment is presented below. The procedure for offline head adjustment using the 800 Disc Storage Subsystem Tester is provided in the Model 800 Operator's Manual.
4.6.3.1 Tools Requilred
Tools required are the Head Alignment Kit (PIN 215970) and a CE Disc Pack. To adjust heads in the RP06 drive, the CE Pack to use is PIN 335001.
Use PIN 320100 for the RP05 drive.
The Head Alignmnt Unit (part of Head Alignment Kit) indicates the presence or absence of valid data and the magnitude and direction of misalignment when valid data is present. The DATA INVALID indicator lamp indicates the former, and the MICf~OINCHES indicator the latter. When DATA INVALID is out, valid data is pres.ent. Note thE! following when using the Head Alignment Unit:
• The MICROINCHES indicator indicates the selected data head alignment with respect to the servo head.
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• An indication of 0 means the head is in perfect alignment. Deflection of the indicator in either direction indicates the number of microinches of misalignment in RP05, and twice the number of microinches of misaligln-ment in RP06.
• The direction of deflection indicates the direction in which the data head is misaligned.
• For RP05, the alignment cylinder is Cylinder 245. At this odd alignmEmt cylinder, a positive (right-hand) indicator deflection means the data head is ahead of the servo head (offset towards spindle centerline), and! a negative (left-hand) deflection means it is behind the servo head (offset away from spindle centerline).
• For RP06, the alignment cylinder is Cylinder 496. At this even alignmEmt cylinder, a positive (right-hand) deflection means the data head is behind the servo head (offset away from spindle centerline), and a negative (Ie,ft-hand) deflection means it is ahead of the servo head (offset towards spindle centerline).
• For RP05/6, RESET HAR and ADVANCE HAR switches in the He,ad Alignment Unit have no effect and are not used.
When the DATA INVALID lamp is lit, valid data is not present for one of the following reasons:
• On Track signal is false.
• Alignment Carrier signal is not present because:
a. CE Pack is not loaded.
b. Head is grossly misaligned beyond carrier area.
c. Head Alignment Unit is faulty and must be replaced.
4.6.3.2 Checking Alignment
1. Select WRITE PROTECT drive mode. Install CE Pack.
2. Slide logic gate fully forward. Turn off drive dc power.
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3. Connect alignment unit's interface cable to B04 slot of logic assembly (see Figure 3-1 for drawing of location).
4. Turn on dc power. Press START switch.
5. Wait until the servo makes a first seek to Cylinder 000. Verify that the alignment unit's DATA INVALID lamp is lit, and extinguishes when the unit is switched to CALIBRATE.
6. Seek to alignment cylinder.
7. Assure that thermal equilibrium is established, as is required before checking alignment or adjusting alignment. Minimum requirements are:
a. With the wind tunnel in the closed position, the drive must operate in a track-following or seek mode for at least 20 minutes. Any disc pack may be used for the first 15 minutes; however, the CE Pack must be used and the heads positioned at the head alignment cylinder during the last 5 minutes.
b. The CE Pack must reach thermal equilibrium by running on a drive for 20 minutes, or by being used as described in a. above.
8. Set alignment unit's CALIBRATE/DRIVE READOUT switch to CALIBRATE. DATA INVALID lamp must be out, and MICROINCHES indicator must be at 0 ± 10 microinches. If out of tolerance, problem could be in either drive servo system or head alignment unit.
9. Release switch.
10. Select head 00-18. If the MICROINCHES reading is not ±75, head alignment is required.
4.6.3.3 Adjusting Alignment
1. Perform steps 1 through 6 in paragraph 4.6.3.2.
2. Open wind tunnel.
3. Engage carriage safety lock (Figure 4-10).
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