Atari 800XL Owner's Manual page 8

If it looks like this,
loosen the screws hold-
ing the U-shaped slider
and move the slider to
the position marked 300
OHM (or 30011).
If it looks like this, in-
sert the tiny wire into the
hole in the center of the
antenna terminal.
5.
Plug the connecting
cable into the COM-
PUTER connection on the
TV Switch Box and into
the jack labeled SWITCH
BOX on your computer.
6. Move the switch on
the TV Switch Box to the
COMPUTER position.
7. Connect the two-
pronged plug on the
AC Power Adapter to
an electrical outlet. The
round plug goes in the
computer's POWER IN
jack.
8. Turn on your TV set
and tune it to Channel 2
or 3-whichever channel
is weaker in your area.
9.
Set the Channel Select
Switch on the computer
to the same channel.
After you turn on your
computer, you may need
to adjust the TV's fine-
tuning knob to improve
reception.
10.
A few seconds after
you turn on the main
power switch on the com-
puter, the screen shows
the word READY from
the ATARI BASIC Pro-
gramming Language.
If you leave the com-
puter on one display long
enough, the colors on the
screen begin changing to
protect your TV set.
When you turn off the
computer, wait 3 to 5
seconds before turning it
back on.
6