Commodore 1541-II - Turning on the Power

After plugging the power supply into the disk drive and a suitable outlet, find the black
cable that goes from the disk drive to the computer. It is called a serial bus cable to
describe the way the computer, and other accessories communicate with each other
through its wires. It has an identical 6-pin DIN connector at each end, which like the
power connector can only go in one way—with the dimple in the side of the plug facing
up.
To plug in the serial bus cable, find the dimple on the side of the metal part of the
plug and turn that side up. Then push it straight into one of the two serial bus connectors
on the back of the disk drive. The other end goes into the similar connector on the back of
your computer, marked '*serial bus." If another accessory, such as a printer, is already
connected there, unplug the other device's cable from the computer, and attach it to the
spare serial bus connector on the back of the 1541. Then install the serial cable from the
1541 in the serial bus connector on the back of the computer (Fig 3.A.)
If you have more than one disk drive, each added disk drive's serial bus cable is
plugged into the second serial bus connector on the back of the previous disk drive, like a
daisy chain (Fig 3.B). However, don't connect the other(s) until you've learned how to
change their device numbers, as no two disk drives can have the same device number.
We'll cover ways of changing disk device numbers in Appendix A. Until you are ready to
read that section, you may find it easier to leave your extra drive(s) unconnected.
TURNING ON THE POWER
With everything hooked up, and the disk drive empty, it is time to turn on the power.
You can turn on the power to the disk and other devices on the serial bus (connected via
serial cables) in any order you like. Just be sure to either turn on the power to the computer
itself last, or to. use a multiple outlet power box with a master switch to turn everything off
and on at once. When everything is on, including the computer, the disk drive will go
through a self check for a second or so, to be sure it is working correctly. After the drive is
satisfied with its own health, it will flash the green light once, and the red power-on light
will glow continuously. At the same time, the computer will be going through a similar
self-test, and displaying its hello message on your TV or video monitor. Once the green
light on the disk drive has flashed and gone out, it is safe to begin working with the drive.
If the light doesn't go out, but continues to flash, you may have a problem. Refer to the
troubleshooting guide for help.