Hard Drive: MINISCRIBE: M8425F 21MB 3.5"/HH MFM ST506
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
Layout
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.
Jumpers
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.
Install
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.
Features
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.
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