~OCP ENABLE
PLUG-I N PHOTO- PHOTO-SENSE (REMOVED)
"',"',',"", ",,~_TAPE CLEANER
_~ _ _ _ ..-..._ READ / WRITE HEAD
CAPSTAN
Figure 39. Head Assembly Replacement VI-14
1. Swing open the transport deck as described in subsection 3.
2. Remove the head connectors P2 and P5 (refer to
Figure_37) from the Data Electronics module mounted on the left side of the transport box, using an appropriate size slot screw driver. Do not use fingers for this purpose so that the possibility of damaging connector wires is eliminated.
3. Remove the four cable clamps holding the cables to the transport casting.
4. Remove the overlay per section 4.
5. Remove the three large Allen screws (item 1, Figure 39) fastening the head plate assembly to the deck. Be sure to support the head assembly to prevent damage when removing the screws. Observe the location of shims under the head plate and replace in the same position when installing the new head plate.
6. Remove head assembly.
7. Following the same procedure in reverse, install new head assembly_
8. Perform the tape tracking check described in sub-section 13.1
9. T"'\ _ _ .t= _ _ ...
rt:::L LUL1U the Data Electronics
subsection 18.
9.1 REPLACING THE PHOTOSENSE UNIT
The EOT/BOT photosense unit is a plug-in type. To replace unit, slide i t off the connectors and install new one. Refer to subsection 17.1 for the adjustment procedure.
9.2 CLEANING THE TAPE CLEANER
1. Brush away the loose particles.
2. Clean the blades thoroughly with IBM cleaner PiN 453511 using Q-Tip applicator.
VI-IS
10.
10.1
10.2
CAPSTAN AND CAPSTAN MOTOR REPLACEMENT CAPSTAN ONLY
The capstan can be removed and replaced by releasing the Allen screw on the top of the capstan motor shaft holding the shaft by the flats provided. Note the orientation of the capstan before removing it, and ensure that i t is re-placed in the same position. Capstan speed adjustments are specified in subsection 17.2.
CAPSTAN DRIVE ASSEMBLY
Replacement of the entire capstan drive assembly (capstan and capstan motor) should be done in accordance with the following procedure:
1. Turn unit power off at the control panel and
dis-connect the power cord, or use switch Sl located near the fuse bank.
2. Remove the capstan (see subsection 10.1).
3. Remove the tachometer plug P9 from the Servo Electronics module. Remove the tie wraps so the plug wires are free to move.
4. Note the position of the (+) and (-) power leads and then remove the leads.
5. Remove the four Phillips screws holding the motor to the transport deck. Remove the shims between the deck and the motor. Remove the motor.
6. Replace the motor and install capstan.
7. Plug the tachometer lead P9 into the Servo Electronics module.
8. Connect up the (+) and (-) leads to the motor terminals.
9. Perform the adjustments for speed and start/stop ramps as described in subsection 17.2.
10. Machine must be retracked according to 13.2.
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10.3 CALCULATING CAPSTAN SPEED ERROR
The 50/60 strobe disc "is inserted into each capstan. The inner strobe is for 60 Hz and is marked such. It is to be viewed with the corresponding AC light (such as fluores-cent). The 50 Hz disc operates with a 100 Hz source,
whereas the 60 Hz disc requires 120 Hz source. The disc image will appear stationary at 25, 37.5 and 75 ips only.
The error from nominal for the mentioned speeds is:
E =
where V is nominal speed in ips, and T is the time in seconds for the image to drift one revolution. If the error exceeds 1%, readjust speed per paragraph 17.2.
11. VACUUM BLOWER BELT REPLACEMENT
1. Turn unit power off at the control panel and
disconnect the power cord, or use switch Sl located near the fuse bank.
2. Swing open the transport deck.
3. Remove the 5 Phillips screws (item 1, Fiqare 40) securing the blower cover. Remove cover.
4. Loosen the 4 Allen screws (item 2, Figure 40)
securing ~ne moun~~ng p~a~e. Slide the motor toward the blower assembly enough to allow the belt to be removed. (Access to these screws is gained through the 3 holes in the motor pulley.)
5. Install new belt with the gear teeth facing outward.
6. Using a belt tension tool as shown in Figure 40, adjust the belt tension for 5 pounds of tension when measured with the Gates 5M tensionmeter.
12. GUIDE ROLLER BEARING REPLACEMENT
Roller guide bearings, which control tape motion to and from the head, can be replaced without destroying preset tracking adjustment if appropriate care is exercised.
(See Figure 41.)
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<:
H I
~ co
Figure 40. Vacuum Blower Belt Adjustment
1. Note the position of each part when disassembling the roller guide. During reassembly each part must be positioned in the same manner as removed.
2. For the roller guide in Figure 41A remove the re-taining ring, item 1, at the shaft end and remove the guide. For the roller guide in Figure 4lB the socket head screw, item 11, holding the cap in place must be loosened first to access the retaining ring.
3. Insert new bearing(s).
4. Replace the roller guide.
5. When replacing item 10, maintain .015 inch clearance with item 5, to ensure the drum turns freely.
6. The mechanical alignment of these guides is accom-plished through the use of a height gauge (WANGCO PiN T00032), the use of which is illustrated in Figure 42.
The guides are to be set to .504/503 inches from the chamber base to the upper guiding edge of the roller guide.
7. To adjust guides (in Figure 41B) loosen the socket head screw, item 8, and adjust for proper indicator
reading. To adjust guides, (in Figure 41A), remove the re-taining ring and add or remove shim as required for
correct indicator reading.
13. TAPE TRACKING
Tape tracking is the mechanical adjustment of elements in the tape path which contribute to the static and
dynamic skew of the tape over the read/write head, as well as the proper alignment of the tape edges between the file
and fixed reels consistent with proper tape handling
(i.e., without damaging the tape). If retracking is found to be required, i t is necessary to afterwards check the Read Stack Azimuth alignment per the procedure described in paragraph 13.3.
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