Hardware Troubleshooting

Ideally, this troubleshooting guide will develop to be a flowchart of things to check.

Power
Symptoms
 * nothing is happening
 * strange things are happening
 * could be caused by low voltage


 * motors appear to have no coherent signal
 * could be caused by no MUX power


 * some motors aren`t working
 * could be caused by low voltage

Check
 * is there proper voltage at the power pins on the chips, DB9s, and other connectors furthest from the power source
 * if not, look for broken traces, blown fuses, broken wires; trace both ways using the multimeter

Motors
Symptoms
 * jittery response
 * see Noise for tips on noise reduction
 * could be caused by no MUX power
 * could be caused by overlaying signal and power lines, creating interference
 * could be low voltage


 * no response
 * something is broken

Check
 * are motor control signals actually being sent
 * are any wires broken
 * is the RC transmitter fully charged (maybe the rechargeable batteries dont provide enough power)
 * is everything powered
 * does the motor work, check when it`s plugged in directly to the Pololu or RC receiver
 * if this doesnt work, make sure the controller isnt broken before tossing the motor
 * does the motor controller work, check a known good motor with the Pololu and RC receiver directly
 * if this works, it`s likely a MUX problem, either a broken trace or a power issue

Sensors
Symptoms
 * no data is returned
 * is it plugged in to power, and proper signal port
 * is a proper level-shifter used, connected the right way


 * data is frequently failing it`s checksum
 * data path is being corrupted


 * data appears to be wrong
 * is the orientation of the sensor correct
 * are all the proper sensor pins connected


 * sensor does not respond when talked to
 * is the voltage level of the signals compatible, ie RS485 level, use a scope to see

Check
 * are the signal wires overlayed with power wires, which will cause Noise
 * does the sensor`s connection show the proper voltage for power
 * are the voltage levels on the RS232/TTL board correct? Reference RS232 Converter

Circuit Boards
Symptoms
 * usually shown through other symptoms, ie no data, no power
 * heating up

Check
 * broken traces, wrong pins connected, use the Datasheets to confirm layout, missing components