The TU8l/IA8l is a cabinet-enclosed, horizontally mounted unit designed to provide front access for both operator and maintenance functions. Operator access for tape mounting is via the hinged top cover. Maintenance access to the underside of tne tape deck is aChieved by opening the top cover and front door and releasing the deck latch located at the left underside of the tape deck. Releasing this latch allows the tape deck to pivot such that the underside of the deck is positioned to the front of the cabinet in a vertical position.
The input power cord and interface cables enter the cabinet at the rear bottom of the unit. Access to this area is via a hinged rear door.
1.3.1 Tape Deck - Top
Refer to Figure 1-3 for component locations. The following components are located on the front of the transport. A brief description of the components and their function is provided as follows.
POWER SUPP\.Y
C aRcuaT alllaKER
__ SUPPLY RilL
~~~ _ _ _ -,=---TAKE-UP --EEL
~m~r;:;;;~~--CONTROL PIlNEL
1 I
I
• ! I'02801-104
1.3.1.1 Supply Reel - The supply (rear) reel is mounted on a bearings, thus reducing ounce} tape tension by reel motor. The air magnetic heads.
The air bearing/tension sensor assembly control air pressure across the air tape friction and providing constant (8 tne corresponding action of the supply bearings also guide tape across the
1.3.1.4 Magnetic Head Assembly The magnetic head is a dual-gap read/write unit designed to perform the read/write functions in a 9-track PE or GCR mode. The dual-gap head allows a write-to-tape operation, read-only operation, or read-arter-write operation. A full-widtn erase head is also provided to erase the tape by DC saturation in the forward reverse direction. The vacuum system directs the stripped particles through a screen and into a filter.
1.3.1.6 BOT/EOT Assembly - Load Point/End of Tape is detected optically. Photo-transistors detect light reflected from BOT and EDT markers on tape. A no-tape-present condition is
1.3.1.8 Power Supply Circuit Breaker The power supply circuit breaker is located at the right rear corner of the tape deck. In the OFF position (0 side pressed), l.nput ac voltage is removed from the power supply" The host controls the ON-OFF state of the input power to the transport by means of a power switching cable. Therefore, during normal use, the power supply circuit breaker should be in the ON position (1 side pressed).
1.3.1.9 Top Cover Interlock - The transport is equipped with an interlock -switch/top cover latch located at the lower left corner of the tape deck. This interlock is basically a safety device to prevent reel motion, unless the front cover is closed
and secured.
-1.3.2 Tape Deck - Bottom
Refer to Figure 1-4 for component locations. The following components are located on the boteom of the tape deck. A brief description of the components and their function is provided as follows.
1.3.2.1 Tape Deck Latch - Tnis latch enaDles the tape deck to be placed in the maintenance position for access to the bottom
tape deck assemblies.
1.3.2.2 Power Supply - The power supply accepts the input AC voltage from the 874 Power Controller and converts it to six
(+5, -6, +15, -15, +25, +38) DC output voltages. The supply contains a line filter, unit circuit protectors, on/off circuit breaker, logic master clear circuit. cooling blower control, pneumatic pump motor controi, and voitage and current monitors.
1.3.2.3 Pneumatic Pump and Filter/Regulator System The pneumatic pump is a 120V (60 HZ) or 220/240V (50 HZ) AC inductor motor with a 4-blade, carbon vane pump. The compressor output air is routed to a filter where any carbon particles are removed before distribution to tape deck components. Mounted directly onto the filter is a piston-type pressure regulator which maintains a constant 2.0 PSI output to the upper and lower air bearings. The vacuum portion of the pump draws air from the tape cleaner.
If the TU81/TA81 does not receive a new command from the host within one minute, transport automatically shuts down the pneumatic pump (compressor) and removes power from the reel motors. If the transport has entered the shut-down mode, execution of the first command received from the host is delayed
LOGIC CAGE
Figure 1-4.
POWER .-~::-:-:-- AMPLIFIER -n-jj---~~
__
S UP PLY-REEL MOTOR
POWER
~---SUPPLY
02BOl-105
TAPE DECK COMPONENT LOCATIONS - REAR VIEW (DRIVE COVER REMOVED)
1.3.2.4 Power Amplifier Module - The power amplifier module receives the low voltage analog signais from the control logic and outputs a higher voltage,high current to the reel motors.
Outputs are dependent on the requirements of the velocity and tension servo systems.
1.3.2.5 Cooling Fan Assembly The cooling fan is a squirrel-cage type assembly located at the rear of the power supply. Cooling air is drawn across the rear deck assemblies and_ through the power supply.. The fan motor is compatible with either 120 or 240 volt operat10n.
1.3.2.6 Logic Cages These two metal cages, mounted vertically under the tape deck, serve as the mounting and security enclosures for the six logic modules. One cage holds the Formatter Read module, the Formatter Write module, and the Interface Controller module. The external I/O cable(s) plug into connector(s) on the cage mounting plate. The other logic cage holds the Read Amplifier module, the Write Driver module, and the Servo-Control module. The modules are inserted into top and bottom hinges at the rear of the bracket assembly and are secured with thumb screws in the normally closed position@
Releasing the thumb screws allows the hinged modules to be positioned for access to components.
1.3.2.7 Reel Motors The reel motors are conventional, permanent-magnet DC motors. The supply reel motor works in conjunction with the upper and lower air bearings to control tape tension across the recording surface of the magnetic head.
The air bearings sense the proximity of tape via air pressure
~~A ~ ~ e-F-Fe".. a""~ 'U'~"e ... 10 ",,....oS8""".o s.onso"'S Th.o Q~nSO"'A
a L A U , .... .L&. . L . llw'-, ... . L v a . ' - .... L&. ... t'~"""' ... '"-'" ,... ... --- ... _ .... __ - __
cause the servo to maintain a constant tension by action of the supp ly ree 1 motor. The take-up ree 1 motor has a lOOO-segment tachometer attached which provides velocity control.
1.3.3 Control Panel (Front Door)
The control panel includes a set of operational control switches, indicators, and a display located at the top right of the front door. These controls enable the operator to initiate and monitor on-line operations and the off-line diagnostic routines.