GENERAL
To maintain the high data integrity of the drive, it is necessary to follow certain special precautions and procedures per-taining to the disk pack and heads. These precautions and procedures will minimize the possibility of destructive head to disk contact (head crash) and subsequent loss of data. In addition to preventive measures, these discussions also describe methods of detecting and recovering from a closed. Latching should occur only after the cover seal has been compressed slightly. The pumping action of the spinning cover (latched). Resistance should be felt while trying to Fil-ter procedure).
3-4 switch is correctly positioned
(see Heads Loaded Switch damaged through impact, excessive pressure or abrasion.
• Never lift or hold a disk pack by any of the recording disks, as permanent damage will result.
• Clean the outside (interiors should also be cleaned if con-taminated), surfaces of the pro-tective covers periodically to remove any build-up of dust that protec-tive canisters.
• Do not allow the pack to rest on from accumulating inside the covers.
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• Replace cracked. disto~ted. or otherwise physically damaged pack covers. pack to canister identification.
• The temperature of the disk pack must be stabilized to the temper-ature of the room in which the drive is operating.
3. Environment
• Install the drive in a room which is kept carefully dusted with particular attention given to keeping a smooth floor mopped and punch equipment. These machines can generate a lot of paper. sticky characteristic. The ab-solute filter on the disk drive at-traction and accumulation by static electricity.
• Disk packs and disk drives must con-struction is absolutely necessary make certain that protective steps are taken to avoid designed to operate successfully over a wide range of ambient air potentially destructive particles out of the head/disk gap.
4. Maintenance
• Do not. under any circumstances. trained personnel.
• Control Data does not recommend
• Do not store pack on 'drives -vibration will shake them off.
• Never lift or hold a disk pack by any of the recording disks. as permanent damage and or contamin-ation will result. accumulating inside the covers.
• Do not place disk pack identify-ing labels anywhere except out-side the top protective cover assembly. The pack serial number may be used to maintain correct pack to canister identification.
• Do not eat. smoke. or allow bev-erages near the drive or pack.
DETECTION AND RECOVERY General
Previous sections have been concerned with precautions to be observed and preventive maintenance steps to be taken to minimize
Head Crash Detection
It is important that the drive operator be aware of a number of head crash signals and warnings provided by the drive it-self. These are described in the follow-ing paragraphs.
3-4.2
CAUTION
Should the conditions under 1. 2. or 3. below. be de-tected. shut down the drive at once. Under these con-ditions the pack should not be installed on another drive without first ensur-ing that the pack has not been damaged or contamin-ated. (See "Evaluate the Disk Pack" and "Disk Pack Inspection and Cleaning" in this section). Also. do not attempt to operate the drive with another disk pack until full assurance is made that no damage or contamination has occurred to the drive heads or to
Under conditions of increasing con-tamination in the air cushion on definite warning signal.
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Guide For Determining The Cause Of Head Crashes operation when the failure occur-red. Had anything unusual the disk condition". manually turn the pack (by rotating with the top trim shield) and verify that the head to disk spacing re-mains constant.
83311300 AJ the head assemblies (particularly those which have not crashed). position. Traverse the carriage repeatedly between the carriage front stops and the unload cams.
If resistance is found. check for the following possible causes:
bound velocity transducer: flex lead retainer mispositioned and is striking the rail bracket:
worn rail: bad carriage bearing:
obstruction caught on the magnet;
foreign material on the rails.
Retract the carriage to the full retract position.
b. Connect the power cord and turn on the AC breaker. Check for adequate air flow entering the shroud area. If questionable.
either compare with another drive
look for possible foreign materi-al (paper. plastic. etc.). If contamination exists. try to de-termine the type and its possible source.
3-4.3'
e. Note head positions then remove all heads for evaluation and cleaning.
4. Evaluate the Heads
a. While making head-pack observa-tions in the drive. if i t was possi-ble mechanical failure differ-ences such as bent gimbal springs. etc.
c. Return non-recoverable heads to the manufacturer for further analysis.
Using observation window in shroud and high intensity light. solution contact the rubber gasket in the pack access cover.
5. Clean the rails and carriage (if crash debris was coarse). Remove the magnet and the carriage and coil assembly if necessary.
6. Clean the air system duct surfaces with head cleaning solution.
7. Replace the carriage and coil assem-bly and magnet if removed. Ensure that the carriage motion is smooth and unobstructed.
8. Consult the paragraph on head-arm replacement criteria in the repair and replacement section of this man-ual before installing the heads.
Replace any heads that are defective per these criteria. Replacement heads should be new or those that have been cleaned by properly trained personnel. Ensure before replacing any undamaged heads that their spoiler holes are free of the characteristic fine dust which they collect when a crash occurs. head crash recovery procedure start-ing from step 1.
12. Enable the voice coil drive. Load a scratch pack. Using a field test unit perform a sequence forward write operation. covering the entire pack. Read back for ten minutes first sequencing forward over th~
entire pack then performing random seeks. Look for error free
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