Hard Drive: NEC: D5126 20MB 5.25"/HH MFM ST506

D 5 1 2 6    NEC
NO MORE PRODUCED                                      Native|  Translation
                                                      ------+-----+-----+-----
Form                 5.25"/HH              Cylinders     615|     |     |
Capacity form/unform    20/      MB        Heads           4|     |     |
Seek time   / track  85.0/18.0 ms          Sector/track   17|     |     |
Controller           MFM / ST506           Precompensation   128
Cache/Buffer               KB              Landing Zone      664
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                 |
Power: sleep              W     Humidity     %                 |
       standby            W     Altitude    km                 |
       idle               W     Shock        g                 |
       seek               W     Rotation   RPM
       read/write         W     Acoustic   dBA
       spin-up            W     ECC        Bit
                                MTBF         h
                                Warranty Month
Lift/Lock/Park     NO           Certificates                                  

Layout

NEC MFM DISKS

  +---------------------------------------------------------+
  |                                                         |XX
  |                                                         |XXJ2
  |                                                         |XX
  |                                                         |XX
  |                                 Terminator  +-------+   |x J4
  |                                 Resistor    |  SW1  |   |
  |                                 ON/OFF Switch-------+   |XX
  |                                                         |XX
  |                                                         |XXJ1
  |                                                         |XX
  |                                 Drive Address-------+   |XX
  |                                 Switch      |  SW2  |   |XX
  |                                             +-------+   |XX
  |                                                         |XX
  |                                                         |
  |                                                         |XXPower
  |                                                         |XXJ3
  +---------------------------------------------------------+

Jumpers

NEC MFM DISKS

Jumper Settings
===============

 D512X, D5146 etc.
 -----------------
  +-----------------+
  | x . . . . . . . | ON
  | . x x x x x x x | OFF
 DS-1-2-3-4-------R-+
    +-+-+-+       +------------- Radial Bit, Always set to OFF
      |
      +-------- Drive Select (set only one bit to ON)

   Terminator Res.
  +-----------------+
  | x x x x x x x x |ON
  | . . . . . . . . |OFF  Terminator ON, means active
  +-----------------+

 D3126, D3142, D3146H, D51X6H etc.
 ---------------------------------
  SW2
  +---------+
  | x . . . | ON
  | . x x x | OFF
 DS-1-2-3-4-+
    +-+-+-+
      |
      +-------- Drive Select (set only one bit to ON)

  SW1  Terminator Res.
  +-----------------+
  | . x x x x x x x |ON
  | x . . . . . . . |OFF  Terminator ON, means active
  +-R---------------+
    +------------------ Radial Bit, always set to OFF!

Only the last drive on the cable must be terminated.

J1 Connector for control signal interface
J2 Connector for data signal interface
J4 Frame Ground

Features

NEC MFM DISKS

Installation Procedure
----------------------
Set the correct setup type and perform a low level format, in the
most cases can the media defect list be entered in this step. If you
cannot find a correct Setup Type (esp. for D3142) use either a lower
cylinder count or special disk installation programms like DISK
MANAGER from ONTRACK or SPEEDSTOR from STORAGE DIMENSIONS.

Run under DOS FDISK and DOS FORMAT, the drive becomes bootable with
the command: FORMAT C:/s.