1551 / SFS 481
![[Picture of 1551, 7k JPEG]](pics/1551.jpg)
Pic. 1: Black is beautiful
Technical details
Documentation
Description
Over two years passed, until Commodore presented a floppy drive dedicated for
the C264 series (that was in fall 1986). It sold
amazingly cheap, for about DM400 [1]. As opposed to all other
Commodore drives (save the ones for the CBM 2/3/4/8xxx series), the 1551 - or
SFS481 which was its originally planned name - features a parallel bus, but as
usual, Commodore did not take full advantage of it, and made it only about
five times (?) faster than the 1541.
Apart from the speedup itself, the drive differs from the 1541 in these
features:
- Uses Mitsumi drive mechanics with turn-down lever
- No serial bus jacks anymore
- Connects to expansion port of Plus/4
- Starts disk motor on insertion of disk for better centering
- Minor bug fixes in the firmware (ROM)
- Two new commands:
- %R sets the number of trials for reading (when errors occur)
- %S sets the sector gap
Notes:
- Like the 154x drives, the 1551 is single sided, so that buying one of
these usually involves buying a disk notcher to use the second side
(which is not recommended, but everybody does it :-), though a normal
hole punch will do, too.
- You can change the device address permanently. I'm not sure, but I
guess that you have to open jumper JP1 between 6510T and
6525. Will verify that when I have time.
- This drive cannot be modified for 240V operation.
[1] 64'er 8/86, p.164, Vorschau: 'Die Floppy 1551'
[2] 64'er 9/86, p.24, Der C 16 bekommt Flügel
[3] RUN 10/86, p.20, Floppy 1551 für C16 und Plus4
Updated: March 23rd, 1998
Created: March 23rd, 1998
Status : NOT VERIFIED!
Site copyright © 1997 by Marc-Jano Knopp
This document is part of MJK's Commodore 64 & LCD Page
Brought back to life by Peter Schepers, Dec 10, 2005 because I really liked this site!