IBM PCjr Manual page 240

6-98 Sound Test
Part 6 is a burst of sound that sounds
like a television turned to a blank
channel. After this part of the Sound
Test is complete, the First IBM PCyr
Test Menu Screen appears.
Press i
Did you hear Part 6 of the Sound
Test?
YES - Go to Step 12.
NO - Go to Step 7.
If you are using a television go to
Step 8.
If you are using a display with no
external sound connected to the rear
of your IBM PC/>, go to Step 10.
If you have an external sound system
connected to the rear of your IBM
PCyr, go to Step 11.