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Troubleshooting
Most Likely Problems
By far most problems will boil down to one of three things, bad (cold) solder connections, bridged
(shorted) solder connections or improperly oriented components. Additionally there may be one or
more pins improperly inserted in the socket for the microcontroller. Check these things where a
problem is suspected.
Start with a DC voltmeter and the negative lead must be affixed to ground (the minus lead of either of
the electrolytic capacitors is fine). The voltmeter should have high input impedance. These are fairly
cheap nowadays, sometimes even free.
First look for smoke. Feel the board for heat. Sources of heat or smoke are an indication of something
major being wrong. Immediately power down and look for shorted traces and incorrectly oriented
components. Make sure that the components are installed in their correct positions and in their correct
orientations.
Assuming no smoke or heat is observed, power down then up.
Did you hear the "roger" R? No look at Power Issues.
Is the green LED flashing? No look at Power Issues.
Power Issues
If the green LED is not flashing check the voltage on pin 1 of the microcontroller. It must be around
3.3V. If so then the microcontroller is powered properly. Check the Low RESET pin (pin 16) for 3.3V.
Check C4 and R7, solder and such.
Still voltage issues? Go to Regulator Issues.
Voltages OK
If voltages are present but we are missing the "roger" R we should check the circuitry near Q2 and SP1.
Check the orientation of Q2.
If voltages are present and we hear the "roger" but the green LED still does not flash check the
orientation of the Green LED and the value of its associated resistor. Look for solder bridges, bad solder
joints and incorrect component orientations.
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