IBM PCjr Manual page 20

Do not turn your IBM VCjr power on yet. Let's take a
minute to review what should happen when you do.
It take's a few seconds for something to appear on the
screen. When it does, it looks like this:
This screen is called the IBM Color Bar screen and it
appears for a few seconds. While it does, your IBM
PCy/- is checking itself to be sure it is ready to go to
work. After your IBM VCjr has checked itself and
finds that everything is working correctly, you hear one
short beep and the screen changes.
2-4 Getting Started
Turn your display or television
power on.
/-N