Device Address Switch
Project: Switch to change the drive's hardware address
Target : 1541 (not 1541-II), 1570
Time : 20 min.
Cost : <2 US$
Use : Possibility to have more than one device attached to
the serial bus without having to switch device addresses
manually on each power-up.
Connect switch(es) to the 1541's internal device address jumpers.
The 1541's circuit board has two jumpers which tell the drives's CPU on
which address it should react. Open the jumpers using a sharp knife and
solder one or two switches to them to choose between two or four different
If you don't install the switch(es), you have to switch off all drives on
the serial bus except for one, then type the following:
where 'no' is the device number you want the floppy to have. Then switch
on the next floppy drive and set its device number the same way you did
with the first drive. Proceed until all drives are switched on. Note that
this procedure must be repeated every time you switch on a drive!
- 1 or 2 single-pole snap switch(es)
- 1 or 2 ~30 cm two-core cable(s)
- Disconnect drive, then open case.
- Search for the two jumpers near capacitor C46, possibly
located between transistors Q4 and Q5.
On a few boards the CIA is on position UAB1, in this case
the two jumpers are directly in front of pins 15 and 16.
- Open the jumper(s) using a sharp knife or similar.
- Solder the first cable to a switch, then solder one lead to
one side of jumper 1 and one lead to the other side. If you
want to use two switches, do the same with the second
- Connect power plug.
- Switch your C-64 and your 1541 on. After the startup screen
appeared, type LOAD"$",x and hit [RETURN], where x is one of
8,9,10 or 11. The 1541 should react on exactly ONE device
address, which corresponds to the following jumper settings:
J1 J2 | Addr
closed closed | 8
open closed | 9
closed open | 10
open open | 11
- If everything works fine, attach the switch(es) to the case
and close it again.
- You did not attach the switch(es) to the right jumpers.
Updated: April 26th, 1998
Created: February 4th, 1997
Status : Verified on September 30th, 1997
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!