Arduino Nixie Clock v6 Operating Instructions Manual page 11

If the LED does not come on, turn off immediately to avoid damage to the components.
If all is well, proceed to the next step. If not, check carefully the orientation of the components and the
power leads. Diode D1 protects the board from having the power connected inverted.
If the LED comes on, check for a few seconds that the 7805 does not heat up. It should stay almost cold.
Hint: The resistor color code 2.7k
The color code for the 2.7k resistor is:
RED = 2
VIOLET = 7
BLACK = 0
BROWN = 1 (1 zero in this case)
Brown = 1 (1% Tolerance)
= 2 7 0 0 with 1% tolerance
Hint: The 100 nF capacitor
The coding on the 100nF capactor is
"104".
This is decoded as:
= "1" then a "0" and then 4 more zeros
= 100000 pF
= 100 nF (1 nF = 1000 pF)
Hint: The 100 uF capacitor
The electrolytic capacitor has a stripe on
it to denote the negative side of the
capacitor. The positive side of the
capacitor (which goes into the "+" on the
board) is the other one!
2.7k resistor
100nF capacitor
100uF capacitor "stripe"