Troubleshooting

Part 1
The first problem we normaly run into is an error when programming the chip. The chip is not recognized. This can be caused by two problems we've identified:
1. JP7 1-5 pins do not connect to the chip. Test these for continuity with a multimeter. Use ohms, not beep (diode) as 3-5 have a 330 ohm resister in series with each and will not beep.

• 1=17
• 2=1
• 3=19
• 4=18
• 5=8

2. If the above proves ok then check voltage at VR1. Vin = 9volts, middle pin is ground (as well as heat sink) and V0ut = 5 volts. If voltage is less than what it should be at both pins, check...

• ground (tab) of VR to ground at battery terminal.
• Diode poliarity
• R1 (especially if voltage is approx 1/2 what it should be (e.g., 3V and 1.5V) at both pins.

3. If voltage is not present, work backwards. Check to insure Diode has correct polarity:

• Excellent description of diodes

4. If all checks ok, test to insure voltage is present at pin #7 of the IC chip. NOTE: the chip will not program unless voltage is present at +vcc (pin #7). The complete circuit for this voltage comes from the battery through D1, into VR1 (9V in/5V out) then to pin #7 of the IC Chip.

Part 2

If you servos will not synch correctly, begin trouble shooting the Line Sensors and Servo circuit.

JP2: Line sensor 1 (JP3 should be tested the same way)

• Check that sensors are in board correctly: dot = pin1, then count counter clockwise on sensor for 2, 3, & 4. Board is labeled for pins 1-4 for each sensor.
• Insure student didn't tape bare wires together.
• P1 connects to R3 (5K ohms) and should have 5 volts P3 connect to R9 (330 ohmes) and should
• P2 goes to ground
• Pin 27 of IC has 5V/.5V (depending on if sensor is covered or uncovered.
• P 3 of JP2 goes to pin 20 of IC.
• P2 & P4 go to ground.