Top side of printed circuit board (PCB) Schematic
Solder all components for the top side of printed circuit board (PCB) R4 R3 C3 J2 C4 C5 J1 – notch in this direction C1 C2 D1-LED – note, short lead in square hole SW1
Making the thermistor lead. Use twisted red/white wire. Thermistor (R2) connected here.
Put clips BC1 and BC2 on the battery. Attached to back of board with rubber band. Note the + (plus) terminal toward switch. Solder on front of PCB.
Check all solder joints to make sure that all have complete coverage of the via. Make sure there are no bridges (overlapping) solder between connections.
Solder on the two antenna wires as shown. Color does not matter. Check length of wire and cut to ~ 7”.
Note, the dot on the LM555 should be aligned with the notch on the socket. Attach the battery as shown. Be sure to put insulating tape on the face down on the battery. The prevents the case of the battery from shorting out the bottom side of the PDB. Insert the U1 - LM555 into the socket
1. Tum the switch on in this position. 2. If the LED lights up, go to the next page. Off On .3 If the LED does not lights up, you got big troubles, but we will tell you how to fix it. See page 13 for trouble shooting your CricketSat.
1. Turn multimeter to Hz%. Off On 2. Connect black lead to pin 1 of J2, Connect red lead to pin 2 of Je. 3. You should read between 1,1000 and 1500 HZ. If you do, you are now ready to calibrate your CricketSat – another document. 4. IF you read zero Hz, then go to page 13 to trouble shoot your CricketSat.
Trouble Shooting your CricketSat 1. Turn off the switch. Remove he LM555 from the socket. 3. You must to re-inspect the bottom of you PCB to make sure you have good solder joints on everything and not bridges. If you find problems and fix them go back to page 10. 2. REMOVE the battery. Off On 4. You will now use your multimeter to check to make sure the circuit has the proper continuity. See page 14. 5. In all your trouble shooting, keep notes on all of the measurements you make.
Trouble Shooting your CricketSat Checking continuity 4. You will now use your multimeter to check to make sure the circuit has the proper continuity. See page 14. 3. Turn the meter switch to the diode/buzzer position. Short the read an black leads together and press the diode/busser button until you hear the buzzer. 1. Be sure your CricketSat is turned off. Remove the LM555 from the socket. 2. REMOVE the battery. Off On
Trouble Shooting your CricketSat Checking continuity 2. These pins are connected together on the PCB (see schematic circled) and thus shorted or have continuity between them. 1. Put the multimeter lead in the socket pins 4 and 8. See pin labeling below, right. Buzzer should sound. 3. If you do not get continuity, then check the PCB to determine what is wrong. • 4. Continue checking other pins: • 2-6 • Ground on PCB to other pins: • To J2 pin 1 • To J1 pin 1 Off On 8 7 6 5 1 2 3 4
Trouble Shooting your CricketSat Checking Resistance 4. You will now use your multimeter to check to make sure the circuit has the proper continuity. See page 14. 3. Turn the meter switch to the resistance - ohms position. Short the read an black leads together and press the range button until you read zero. 1. Be sure your CricketSat is turned off. Remove the LM555 from the socket. 2. Make sure the battery is removed. Off On
Trouble Shooting your CricketSat Checking Resistance and Capacitance 2. Next check between 7 and 6. You will be reading the thermistor ~ 10k ohms at room temperature. 1. Put the multimeter lead in the socket pins 7 and 8. You should get what? Look at the schematic – 2.7k ohms. • 3. Continue checking other pins: • 3 to pin J2 pin 2 – 330 ohms • You can not check resistance across a capacitor or a diode with the resistance setting on the multimeter. Use the capacitance setting on the meter to check capacitance. Off On 8 7 6 5 1 2 3 4 4. If you find errors, maybe a bad component or wrong component.
Trouble Shooting your CricketSat Checking Voltages 1. Put the battery back in and turn the switch on. 2. Turn the meter to Vdc and check between pins 1 and 8 on the LM555 socket. You should get approx. minus 9v. Minus because the red lead is on the ground connection. If voltage is below 9v, change batteries. 3. Look at the schematic and determine other places where you should also get 9v. If no voltage, trouble shoot. What is cause? Off On 4. If you find errors, maybe a bad components. wrong components or bad connections.
If you find problems and can correct them, go to page 11 and repeat check to see if you can get your CricketSat to oscillate.