
T M 2 5 2    TANDON
NO MORE PRODUCED                                      Native|  Translation
                                                      ------+-----+-----+-----
Form                 5.25"/HH              Cylinders     306|     |     |
Capacity form/unform    10/   13 MB        Heads           4|     |     |
Seek time   / track  85.0/ 3.0 ms          Sector/track   17|     |     |
Controller           MFM / ST506           Precompensation   128
Cache/Buffer               KB              Landing Zone      305
Data transfer rate    0.625 MB/S int       Bytes/Sector      512
                      0.625 MB/S ext
Recording method     MFM                            operating  | non-operating
                                                  -------------+--------------
Supply voltage     5/12 V       Temperature *C         4 50    |    -40 60
Power: sleep              W     Humidity     %         8 80    |
       standby            W     Altitude    km    -0.457  3.050| -0.457 12.195
       idle               W     Shock        g        10       |     40
       seek               W     Rotation   RPM      3600
       read/write         W     Acoustic   dBA
       spin-up            W     ECC        Bit
                                MTBF         h      11000
                                Warranty Month
Lift/Lock/Park     NO           Certificates                                  

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                      J   U   M   P   E   R   S
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TANDON   TM252  USER'S MANUAL P/N 179050-001B, 1984

 Jumper Setting
 ==============

 Drive Address and Option Selection
 ----------------------------------
 The drive address and option selection is determined by the
 programmable jumper blocks located on the logic circuit board. If
 jumper configurations are changed, power shoulf be cycled off and on,
 so that the microprocessor can recognize the new configuration.

 +------+----------------+------------+-----------------------------+
 |Option|Function        |Factory     | Usage                       |
 |Jumper|                |Programmed, |                             |
 |      |                |User Access.|                             |
 +------+----------------+------------+-----------------------------+
 |W15   |Drive Select    |      I     |Omit W15 for drive-to-       |
 |      |                |            |controller lines, enabled    |
 |      |                |            |when drive not selected      |
 +------+----------------+------------+-----------------------------+
 |W16   |Index           |      I     |Omit W16 for index-to-       |
 |      |                |            |controller line, enabled when|
 |      |                |            |drive not selected.          |
 +------+----------------+------------+-----------------------------+
 |RTW7  |Read Terminator |      I     |Install only at the end drive|
 |WTW8  |Write Terminator|      I     |for daisy chain data. Install|
 |      |                |            |in all drives for radial data|
 +------+----------------+------------+-----------------------------+
 |S4W9  |Drive Select 4  |      O     |Install one of four plugs    |
 |S3W10 |Drive Select 3  |      O     |only. Plug corresponds to    |
 |S2W11 |Drive Select 2  |      O     |drive address.               |
 |S1W12 |Drive Select 1  |      I     |                             |
 +------+----------------+------------+-----------------------------+
 |U19   |Terminator Pack |      I     |Install at the end drive only|
 |      |                |            |for daisy chain control lines|
 +------+----------------+------------+-----------------------------+
 O = Omit
 I = Install



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TANDON   TM252  USER'S MANUAL P/N 179050-001B, 1984

 Notes on Installation
 =====================

 Mounting the Drive
 ------------------
 The drive can be mounted in any vertical or horizontal plane. Eight
 6-32 tapped holes are provided for mounting: four on each side and
 four on the bottom of the frame. The drive is manufactured with some
 critical internal alignments that must be maintained. Hence, it is
 important the mounting hardware does not introduce significant stress
 on the drive.

 Any mounting scheme in which the drive is part of the structural
 integrity of the enclosure is not permitted. Mounting schemes should
 allow for adjustable brackets or incorporate resilient members to
 accommodate tolerances.


 Tapped Mounting Holes
 ---------------------
 Four on Bottom, four on each side 6-32 UNC x .31 in. (7.9mm) deep,
 8 places.


 Daisy Chain Capability
 ----------------------
 The drive provides the address selection and gating functions
 necessary to daisy chain a maximum of four units at the user's
 option. The last drive on the daisy chain terminates the interface.
 The terminations are accomplished by a resistor array plugged into a
 DIP socket.


 Industry Standard Interface Compatibility
 -----------------------------------------
 The drive is compatible with controllers that use an ST506 industry
 standard interface.


 Dust Cover
 ----------
 The design of an enclosure should incorporate a means to prevent
 contamination from loose items, e.g., dust lint, and paper chad since
 the drive does not have a dust cover.


 Free Air Flow
 -------------
 When the drive is mounted so the components have access to the free
 flow air, normal convection cooling allows operation over the
 specified temperature range.


 Confined Environment
 --------------------
 When the drive is mounted in a confined environment, air flow must
 be provided to maintain specified air temperatures in the vicinity
 of the motors and the circuit boards.


 Interface Connectors
 --------------------
 The electrical interface between the drive and the host system is via
 three connectors. J1 provides control signals for the drive. J2
 provides for the radial connection of read/write data signals. J3
 provides for DC power.


 J1/P1 Connector
 ---------------
 Connection to J1 is through a thirty-four-pin circuit board
 connector. The pins are numbered 1 through 34. The recommended
 mating connector for P1 is 3M ribbon connector P/N 3463-0001, without
 ears. A key slot is provided between Pins 4 and 6.


 J2/P2 Connector
 ---------------
 Connection to J2 is through a 20-pin circuit board connector. The
 recommended mating connector for P2 is 3M ribbon connector P/N
 3461-0001, without ears. A key slot is provided between Pins 4 and 6.


 J3/P3 Connector
 ---------------
 DC power connector J3 is a four-pin AMP Mate-N-Lok connector, P/N
 350211-1, mounted on the component sode of the circuit board. The
 recommended mating connector, P3, is AMP P/N 1-480424-0, utilizing
 AMP pins P/N 60619-4. J3 pins are labeled on the J3 connector. J3
 cabling must be 18 AWG, minimum.

   +-----J3-----+   pin 1    +12 VDC
   | 4  3  2  1 |   pin 2    +12 Volts Return
   +------------+   pin 3    + 5 Volts Return
                    pin 4    + 5 VDC


 Ground Connector
 ----------------
 A ground connector, located on the rear of the head/disk assembly is
 Faston AMP P/N 61761-2. The recommended mating connector is AMP P/N
 62187-1. To realize error rates, it must be connected directly to the
 centrally located system logic ground via an 18 AWG, minimum, cable.



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                      F   E   A   T   U   R   E  S
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TANDON   TM252  USER'S MANUAL P/N 179050-001B, 1984

 General Description
 -------------------
 Tandon Corporation's TM252 drive is a full feature, 12.75 megabyte,
 one-half height, 5-1/4-inch, rigid disk drive. It is a compact data
 storage device containing two 130-millimeter plated aluminium
 recording platters and four recording heads within a sealed housing.


 Purpose of the drive
 --------------------
 The 5-1/4-inch disk drive is a rotating disk memory device designed
 for random access data storage and retrieval. Typical applications
 include word processing systems, entry level microprocessor systems,
 intelligent calculators, program storage, small business computer
 systems, and any application in which low cost, random access data
 storage is required.


 Microprocessor Control
 ----------------------
 The TM252 drive features an onboard microprocessor, providing five
 major functions:

 1. Self-calibration on power-up.

 2. Buffered seek timing for improved access times.

 3. Improved positioning with reduced hysteresis.

 4. Write current switching for optimal recording quality.

 5. Power and track fault detection.


 Air Filtration
 --------------
 A self-contained, recirculating air filtration system supplies clean
 air through a 0.3-micron filter. A secondary absolute filter is
 provided to allow pressure equalization with the ambient atmosphere
 without contamination. The entire head-disk-actuator compartment is
 maintained at a slightly positive pressure to further ensure an
 ultraclean environment.


 Functional Description
 ----------------------
 The drive is fully self-contained, and requires no operator inter-
 vention during normal operation. During the power-up sequence, the
 spindle motor reaches 3,600 RPM, and the positioning mechanism
 recalibrates the recording heads to Track 0. At this time, a Ready
 signal on the interface indicates the drive is ready for operation.

 The head is positioned over the desired track by means of a four-
 phase stepper motor/band assembly and its associated electronics.
 This positioner uses a one-step rotation to cause a one-track radial
 movement. Subsequently, the recording heads can be positioned over
 the desired cylinders, and the data can be read or written from the
 appropriate track by selecting the desired head.

 Typically, the drive uses MFM write and read data recording methods.
 Data recovery electronics include a low-level read amplifier,
 differentiator, a zero-crossover detector, and digitizing circuits.
 No data encoding or decoding feature is provided on the drive.

 The drive has the following sensor systems:

 1. An optical Track 0 switch senses when the Head/Carriage Assembly
    is positioned at Track 0.

 2. An index sensor, which consits of a magnetic pick-up and index
    hole positioned an analog signal when an index hole is detected.


 Seek Time
 ---------
       +----------------------------------+--------+
       |                                  | TM252  |
       +----------------------------------+--------+
       |Track-to-Track         msec. typ. |   3    |
       +----------------------------------+--------+
       |Average                msec. typ. |  85    |
       |                       msec. max. | 321    |
       +----------------------------------+--------+
       |Latency                msec. avg. |   8.33 |
       +----------------------------------+--------+


 Media Defects
 -------------
 Any defects on the media surface will be identified on a defect map
 provided with each drive. This defect map will indicate the head
 number, track number, and number of bytes from index for each defect.
 Each defect shall be no longer than 16 bits. More than one defect per
 track is to be counted as one defect. Cylinders 000 and 001 are
 guranteed error free.


