
M 8 4 2 5 F    MINISCRIBE
NO MORE PRODUCED                                      Native|  Translation
                                                      ------+-----+-----+-----
Form                 3.5"/HH               Cylinders     615|     |     |
Capacity form/unform    21/   25 MB        Heads           4|     |     |
Seek time   / track  40.0/11.5 ms          Sector/track   17|     |     |
Controller           MFM / ST506           Precompensation   128
Cache/Buffer               KB              Landing Zone
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        10 50    |    -40 60
Power: sleep              W     Humidity     %         8 80    |      5 95
       standby            W     Altitude    km    -0.061  3.048|        12.192
       idle               W     Shock        g        10       |     70
       seek          13.0 W     Rotation   RPM      3600
       read/write         W     Acoustic   dBA        45
       spin-up            W     ECC        Bit
                                MTBF         h      30000
                                Warranty Month
Lift/Lock/Park     YES          Certificates     CSA,UL1950                   

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MINISC.  8425F/8438F  PRODUCT MANUAL P/N 1085 REV. F, AUG. 17, 1988

                   +----------------------------------------+
                   |+-J8                                    |XX
                   || | Stepper Motor                 SEL   |XX
                   |+-+ Connector                J15+ +-+   |XX P2
                   |+-J9                           ++ | J2  |XX
                   || | Rezero                   J13+ | |   |XX
                   |+-+ Sensor                     ++ +-+   |
  +----------------+    Connector                     ++    |XX
  |+--J16                                             ||    |XX P1
  |+--+LED                                         RP1||    |XX
  |                                         Terminator||    |XX
  |+-J10                                              ++    |XX
  || |Flex Circuit                                          |XX
  || |Connector                    Spin Motor Connector     |XX
  || |                             J6---+   +--J7 Index     |XX
  |+-+                             +----+   +--+  Detector Connector
  +--------------------------------------------------xxxxxx-+
                                              Power  xxxxxx J3
 Earlier versions of PCBA do not contain J15.



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                      J   U   M   P   E   R   S
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MINISC.  8425F/8438F  PRODUCT MANUAL P/N 1085 REV. F, AUG. 17, 1988

 Jumper setting
 ==============

 x = Jumpers set at factory


 Customer options are limited to drive select addressing (SEL) and LED
 positioning.


 SEL  Drive Select
 -----------------
 As shipped, the drive is preselected for drive select address 1.
 Other drive select addresses may be chosen by removing the 2 position
 drive select jumper to one of the other pairs of pins.
                   +----+
  x              1 |xxxx| Drive select 1
                 2 |O  O| Drive select 2
                 3 |O  O| Drive select 3
                 4 |O  O| Drive select 4
                   +----+


 LED Options
 -----------
 The drive is normally shipped with an LED inserted into a wire trap
 connector. In some applications it is more desireable to have the LED
 extended out to another location. This can be accomplished by
 removing the LED, adding extension leads, and reinserting the leads
 into the wire trap.

 Removal and insertion are achieved by sliding the housing of the wire
 trap towards the center of the PCB releasing the LED, leads, etc.



 Diagnostic and Exercise Routines
 --------------------------------
 The microprocessor performs wake up diagnostics upon application of
 power. If an error is detected, the processor will flash a warning by
 blinking the activity LED. Some errors are fatal in that they do not
 return to the program until power is cycled.

 If no errors are detected, the processor tests Jumper 13 to determine
 its state (open or closed). Briefly, Jumper 13 (Drive Exercise
 Options) is as follows:

 The jumper is left open for normal (online) operations. If the
 jumper is closed, (and left closed) a burn-in (cresendo seeks)
 program will be run. If the jumper is closed and opened during the
 code level display, the sensor adjust routine is initiated.

 J15 low power option. When open, seek to the ship zone is performed
 after no activity for 30 seconds and power is removed from the
 stepper motor.

 Power-up sequence of events is as follows:

 1. Apply power

 2. The microprocessor runs power on diagnostics and then allows motor
    spin up.

 3. Test Jumper 13. If open, go to normal operation. If closed,
    continue to Step 4.

 4. Display code level (5 bits), e.g. 00001

 5. Test Jumper 13. If still closed, continue in cresendo seek
    exerciser mode. If open, run Track Zero sensor adjust.

 6. Recalibrate access, then seek to maximum cylinder.

 7. The LED will display seven zero's (flash code). At this time the
    heads are located over the shipping zone. If power is removed, the
    heads will land in the shipping zone.

 8. If the test is continued the drive will perform a seek to
    cylinder four, (test for seek error) and then seek to cylinder
    zero.

 9. At this point the sequential seek burn-in will begin.



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MINISC.  8425F/8438F  PRODUCT MANUAL P/N 1085 REV. F, AUG. 17, 1988

 Notes of installation
 =====================

 Installation direction
 ----------------------

     horizontally                           vertically
   +-----------------+             +--+                       +--+
   |                 |             |  +-----+           +-----+  |
   |                 |             |  |     |           |     |  |
 +-+-----------------+-+           |  |     |           |     |  |
 +---------------------+           |  |     |           |     |  |
                                   |  |     |           |     |  |
                                   |  |     |           |     |  |
 +---------------------+           |  +-----+           +-----+  |
 +-+-----------------+-+           +--+                       +--+
   |                 |
   |                 |
   +-----------------+

 Drive Orientation
 -----------------
 The drive may be mounted in any attitude.


 Mounting Configuration
 ----------------------
 The Miniscribe 8425F and 8438F quarter size drives are designed to
 be used in applications where the unit may experience shock and
 vibration at greater levels than larger and heavier disk drives.

 Two features which allow greater shock tolerance are the rugged media
 and shock mounts. To take full advantage of the shock mounts,
 however, it is necessary to provide a minimum of 0.1 inch clearence
 on both the top and sides of the drive. This clearence allows for
 movement of the drive during acceleration.

 The drive is mounted using 6-32 screws, 1/8 inch maximum penetration.
 The customer should allow adequate ventilation for the drive to en-
 sure reliable drive operation over the operating temperature range.


 Mechanically isolated mounting points
 -------------------------------------
 Four (4) side mounting and four base mounting points are provided to
 the customer. Each mounting point is mechanically isolated from the
 head-disk assembly.


 Cabling
 -------
 Connect interface cables with connector P1, P2 and P3 to J1, J2 and
 J3 respectively. Iff multiple drives are to be interconnected, remove
 the terminator packs in all but the last drive of the daisy chain.


 Cable Interconnection - 4 Drive System
 --------------------------------------

       HOST
   +-----------+                                +-----------------+
   |           +---o---Control------------------+P1     Drive 1   |
   |           |   |    +-------Data------------+P2               |
   |           |   |    |             +-Power---+P3        ...    |
   |           |   |    |             |         +-----------------+
   |           |   |    |             |         +-----------------+
   |Controller |   o----+-------------+---------+P1     Drive 2   |
   |           |   |    | +-----------+---------+P2               |
   |           |   |    | |           o---------+P3        ...    |
   |           |   |    | |           |         +-----------------+
   |           |   |    | |           |         +-----------------+
   +-----------+   o----+-+-----------+---------+P1     Drive 3   |
   |           |   |    | | +---------+---------+P2               |
   |           +---+----+ | |         o---------+P3        ...    |
   |           +---+------+ |         |         +-----------------+
   |Data       +---+--------+         |         +-----------------+
   |Separator  |   +------------------+---------+P1     Drive 4   |
   |           +----------------------+---------+P2               |
   |           |                      o---------+P3        XXX    |
   +-----------+                      |         +-----------------+
                       DC voltages----+

 ... = Terminator Pack removed

 XXX = Terminator Pack installed


 Terminators
 -----------
 Each drive is shipped with a terminator pack providing the 220/330
 ohn termination for the Control Input Signals. If multiple drives are
 configured in a daisy chain configuration, the terminator pack must
 be removed from all except the last unit on the daisy chain.


 P1 Control Signal Connector
 ---------------------------
 Connection to P1 is through a 34 pin PCB edge connector. The pins are
 numbered 1 through 34 with the odd pins located on the circuit side
 of the Printed Circuit Board. A key slot is provided between pins 4
 and 6.

 The recommended mating connector (J1) is AMP Ribbon Connector, P/N
 88373-3.


 P2 Data Signals Connector
 -------------------------
 Connection to P2 is through a 20 pin edge connector. The pins are
 numbered 1 through 20 with the odd pins located on the circuit side
 of the Printed Circuit Board. A key slot is provided between pins 4
 and 6.

 The recommended mating connector (J2) is AMP Ribbon Connector,
 P/N 88373-6.


 P3 DC Power Connector
 ---------------------
 DC power connector (P3) is a 4 pin AMP Mate-N-Lok Connector, mounted
 on the PCB.

 The recommended mating connector (J3) is Molex P/N 15-24-4048
 utilizing Molex pins P/N 02-08-1201.

       +------------+    1 = +12 Volts DC
       | 4  3  2  1 |    2 = +12 Volts Ground Return
       +------------+    3 = + 5 Volts Ground Return
                         4 = + 5 Volts DC


 Electrical Interface
 --------------------
 The interface to the MiniScribe 8425F and 8438F can be divided into
 three categories, each of which is physically separated: Control
 Signals, Data Signals and DC Power.

 All control Signals are digital in nature (open collector TTL), and
 provide signals either to the drive (input) or signals to the
 collector (output). The Data Signals are differential in nature and
 provide data either to (write) or from (read) the drive.

 The interconnect cable between the drive and controller may be flat
 ribbon or twisted pairs of a length not to exceed 20 feet. The signal
 return lines and ground lines for P1 and P2 should be grounded at the
 controller.



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                      F   E   A   T   U   R   E  S
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MINISC.  8425F/8438F  PRODUCT MANUAL P/N 1085 REV. F, AUG. 17, 1988

 Introduction
 ------------
 The Miniscribe 8425F and 8438F are half-height random access 95 mm
 rigid media disk drives employing Winchester technology. The drives
 utilize a rack-and-pinion actuator, microprocessor control, and open
 loop stepper head positioning.

 The drives feature power up diagnostics, buffered seek and have a
 data transfer rate of 5 Megabit/Sec, and 7.5 Megabit/Second
 respectively. D.C. voltages and physical form factor are the same as
 the 3-1/2 inch half height floppy disk drive.


 Seek time
 ---------
 (Including settling time)   |           |
                             |8425/8438F |
 ----------------------------+-----------+
 Average Single Track *      |  11.5  ms |
 Average                     |  40    ms |
 Maximum                     |  81    ms |
 Average Latency             |   8.33 ms |
 ----------------------------+-----------+

 * Worst Case Single Track Seek: 12.0 ms.


 Reliability and Maintenance
 ---------------------------
 MTBF                     30,000 hours (continuous operation) at 35*C
 MTTR                     30 minutes
 Preventive Maintenance   None
 Component Design Life    5 years



 Media Defect Criteria
 ---------------------

 Model 8425F                 Model  8438F
 --------------------        ---------------------
 6 defects/surface maximum   8 defects/surface maximum
 20 defects maximum          30 defects maximum
 Cylinder Zero Defect Free   Cylinder Zero and one Defect Free

                as shipped from MiniScribe


 Magnetic Field
 --------------
 The externally induced magnetic flux density may not exceed 3 Gauss
 as meaured at the disk surface.


 Drive Mechanism
 ---------------
 A brushless DC direct drive motor rotates the spindle a 3600 rpm.
 The motor/spindle assembly is dynamically balanced to provide minimal
 mechanical runout to the disks. A dynamic brake is used to provide a
 fast stop to the spindle motor when power is removed.


 Air Filtration System
 ---------------------
 Within the sealed enclosure, a 0.3 micron filter coupled with a
 breather filter, provides over the drive live, a clean, above
 atmospheric pressure environment for the heads and disks.


 Head Positioning Mechanism
 --------------------------
 Four (4) read/write heads are supported by a carriage mechanism
 coupled to the stepper motor through a rack-and-pinion motion
 translator.


 Track Zero Detector
 -------------------
 The Track Zero Detector resides on the stepper motor. This optical
 sensor consists of a light source (activated only ehen a seek is
 initiated) and a receiver which when blocked by an interrupter on the
 motor shaft, indicates one of several logical Track Zero positions.
 The microprocessor determines the physical location of Track Zero
 from the redundant logical Track Zeros.


 Message Readout
 ---------------
 Error codes may be generated by the microprocessor to indicate hard-
 ware failures or warnings that are detected during power-on
 diagnostics, burn-in mode, or normal operation. Error codes are
 diaplayed in a "morse-code" type manner. Bits may be interpreted and
 converted into hexadecimal error codes. "Zeros" are indicated by
 a short (1/2 second) flashingn mode. "Ones" are indicated by a short
 (1/2 second) continuous ON mode. Error "Words" are separated by a one
 second LED off time.

    Zero                  = 0.5 second flashing mode
    One                   = 0.5 second continuous ON mode
    Between Bits          = 0.3 second Off
    Between Repeat Cycles = 1.0 second Off

 Listed Below are the binary to hexadecimal conversion values:

  0 = 0000   4 = 0100   8 = 1000   C = 1100
  1 = 0001   5 = 0101   9 = 1001   D = 1101
  2 = 0010   6 = 0110   A = 1010   E = 1110
  3 = 0011   7 = 0111   B = 1011   F = 1111


 Message Definitions
 -------------------
 Code 0 - Microprocessor RAM error
 Code 1 - Microprocessor ROM checksum error
 Code 2 - Interface chip diagnostic failure
 Code 3 - Write Fault latch will not reset
 Code 4 - Index pulse not detected during spinup
 Code 5 - Unable to reach 3600 rpm in 30 seconds
 Code 6 - Unable to stabilize spin speed in 10 seconds
 Code 7 - Unable to maintain spin speed to 0.5%
 Code 8 - Unable to uncover Track Zero sensor
 Code 9 - Unable to cover Track Zero sensor
 Code A - Track Zero interrupter misadjusted
 Code B - Shipping zone error, crash stop misadjusted
 Code C - Carriage stuck during recal error
 Code D - Seek errror during burn-in or recal
 Code E - No hall transitions during spin-up
 Code F - Unexpected interrupt from processor


 Caution/Warning
 ---------------
 The Miniscribe drive is a precision product weighing 1.8 pounds.
 During handling the unit must not be dropped, jarred or bumped.
 Otherwise, damage to the heads and disks may occur. When the drive is
 removed from the Miniscribe shipping container and not immediately
 secured within a chassis through its shock mounts, it must be stored
 on a soft padded surface.

 Failure to comply with the above procedure will render null and void
 all warranties.


