====== NEC FD1157C ======

These drives are compatible with a standard Floppy interface.

===== Specifications ====

^ Capacity       | Formatted: HD 1.2 MiB; DD 700 KiB    |
^ :::            | Unformatted: HD 1.6 MiB; DD 1.0 MiB  |
^ Height         | 1.6 in / 41 mm                       |
^ Width          | 5.7 in / 146 mm                      |
^ Depth          | 8 in / 203 mm                        |
^ Weight         | 2.6 lbs / 1.2 kg                     |
^ Disk size      | 5.25"                                |
^ Heads          | 2                                    |
^ Surfaces       | 2                                    |
^ Tracks/Surface | 80                                   |
^ Track density  | 96 tpi (tracks/in)                   |
^ Dit density    | HD: 9870 bpi; DD: 5922 bpi           |
^ Record method  | MFM                                  |
^ Rotation rate  | HD: 360 rpm; DD: 300 rpm             |
^ Shock rating   | Operating: 10 G; Non-operating: 30 G |
^ Vibration      | Operating: 0.5 G @ 0 - 100 Hz; Non-operating 3 G @ 0 - 100 Hz |
^ Seek time      | Track to track: 3 ms                 |
^ Settle time    | 15 ms                                |
^ Data transfer  | HD: 500 Kib/s; DD: 250 Kib/s         |
^ Power          | +5 V, +12 V                          |
^ Power dissipation | 4.8 watts                         |
^ MTBF           | 12,000 POH                           |
^ MTTR           | < 15 minutes                         |

(Specifications come from {{nec_fd1157c_datasheet.pdf|an online datasheet downloaded from NEC on 2014-08-28}}.)

==== Jumper Settings ====

From http://jope.fi/drives/necflopp.txt:

^ Configuration 1: Non-twisted cable ||||||||||
^  USE  ^  MON  ^  VC  ^  HDE  ^  DEN  ^  M1  ^  DCG  ^  LM1  ^  LM2  ^  DX  ^
|   2   |   1   |  On  |   1   |   1   |  On  |   2   |   0   |   0   |  see note  |
note: Drive 1 (A:) has DX=0, drive 2 (B:) has DX=1

^ Configuration 2: Twisted cable (pin 10-16 twisted) ||||||||||
^  USE  ^  MON  ^  VC  ^  HDE  ^  DEN  ^  M1  ^  DCG  ^  LM1  ^  LM2  ^  DX  ^
|   2   |   3   |  On  |   1   |   1   |  On  |   2   |   0   |   0   |   1  |

note: Drive 2 and controller are on one the same side of the twist, and drive 1 is on the other side. Both drive 1 (A:) and drive 2 (B:) have DX=1.

=== Jumper setting options ===

(* is the default setting.)

^ Head Load Condition      ^  HS  ^  USE  |
| Drive select & head load |  1   |   1   |
| Drive select             |  1   |   2   |
| Head load                |  2   |   1   |
| Drive select & motor on  |  1   |   3   |
| Motor on                 |  2   |   3*  |

^ Motor On Condition ^  MON  |
| Drive select       |   3   |
| Head load          |   2   |
| Motor on           |   1*  |

^ Display Lamp Condition   ^  IUS  ^  USC  ^    LED    |
| Head load                |   2   |   1   |  1 and 4  |
| Head load & Drive select |   2   |   1   |  1 and 5  |
| Drive select             |       |   -   |  2 and 4  |
| Ready                    |       |   -   |  3 and 4  |
| Ready & Drive select     |       |   -   |  3 and 5  |
| Drive select             |       |   -   |  2 and 5  |
| Head load                |   1   |   -   |  1 and 4  |
| Head load & Drive select |   1   |   -   |  1 and 5*  |

Note: "-" indicates that the jumper position doesn't matter.

^ Density Switching ^|||
^ Record density ^ High/Normal density signal ^  DEN  |
| High           | H level                    |   1*  |
| Normal         | L level                    | :::   |
||||
| Normal         | H level                    |   2   |
| High           | L level                    | :::   |
||||
| High           | H level                    |   3   |
| High           | L level                    | :::   |
||||
| High           | H level                    |   Open  |
| Normal         | L level                    | :::     |

^ Rotation Change ||
^ Rotation in normal density mode ^  HDE   |
| 360 rpm ("single speed mode")   |   1*   |
| 300 rpm ("dual speed mode")     |   2    |

Note: A rotation in a high-density mode is 360 rpm for both short plug and "HED"=1 and 2.[sic]

^ Disk Change/Ready ||
^ Disk change/ready signal output condition ^  DCG  |
| Ready signal                              |   1   |
| Disk change signal                        |   2*  |

==== Basic Disassembly ====

⚠️ **Use a J1 screwdriver or you will strip the screws!** Screws on this drive are type J1 JIS screws. [[https://chapmanmfg.com/blogs/news/phillips-bits-vs-jis-bits-whats-the-difference|These are similar to Phillips screws, but not the same.]] 

With the drive flat on a table, with door facing you, remove the screw on the right about midway down the chassis. This screw holds the RF shielding on. With the screw out, the shielding should slide forward towards the drive door. Lift the back up. You should be able to remove the shielding entirely. Reverse the process to put it back.

==== Extras ====

Cleaning video: {{youtube>kCBLJMqTFng?medium}}