IBM PCjr Manual page 50

"L
If you want to go back to the first color, press the Fn
key, release it, and then press the F5 key.
Just for fun, press the Fn key;
release it. Now press the F4 key.
- - 3
then
Press the Fn key; release it. Now
press the F3 key.
then
Pretty screens, weren't they?
Let's try another function key combination. This time:
s^nr
7^.
then
Press the Fn key; release it. Now
press the F2 key.
2-34 Getting Started