J 39916-A CD and Cassette Diagnostic Kit
A 2 minute time period is marked in the motor speed test portion of the tape, which tests the cassette tape motor speed.
This portion of the diagnostic tape also verifies that abnormal sound is coming from the cassette tape player. Incorrect tape speed may cause audio abnormalities.
The tape motor speed is acceptable if it takes from 116-121 seconds for this portion of the tape to play.