Maybe this paragraph will help explain:
Quote:
The microprocessor trainer has provision for manually inserting eight faults. Each one of the eight faults is controlled by a switch located under a key lock cover. Each fault that you are required to troubleshoot will be typical of the faults that can occur in any microprocessor system. In the last exercise of this unit, you will troubleshoot the system to locate these faults inserted by your instructor. The microprocessor trainer needs a +5Vdc power supply to operate. Before troubleshooting, the power supply is checked to specification (+5Vdc + 5%). If, after the power supply check, a problem still remains, the troubleshooting process of the microprocessor begins.
(We might disagree with this particular approach to teaching, but there's at least a rationale.)