Circuit Testing
All electrical construction and wiring should be completed before conducting circuit
testing. Completion of mechanical construction is not necessary.
Make sure that you follow the test procedures below in the order described. This is
essential to ensure that you have wired the components properly. It also minimizes the
risk of permanently destroying any IC due to improper construction or soldering. When
installing ICs to their sockets, pay attention to the polarity. Wrong installation may cause
permanent damage to the ICs.
Test 1A: GND network continuity
The purpose of Tests 1A, 1B and 1C is to make sure that the soldering work of the
power supply network is good. This is done without installing any ICs on the sockets. Do
not insert U2 through U8. Do not apply any power to the circuit. Set your Digital
Multimeter (DMM) to beeping continuity test or resistance measurement. Pick a ground
signal, for example the negative pin of C1. Measure the continuity to every test-point
listed below to ensure that the resistance is less than a few Ohms. Refer to Figure 1 for
ICs and pin locations.
Test 1A: Test-points for GND network
continuity test. No power should be applied.
U1 GND pin
U2 pin 7
U3 pins 3, 5, 7, 8, 10
U4 pins 8, 13
U5 pins 8, 13,15
U6 pin 8
U7 pin 8
U8 pin 8
R1, C1, C2, C3, C4, C5, C7, C8
Power Jack
Piezo Buzzer
Follow the test procedures in the order described
