12. Troubleshooting
One of the LEDs don't light up:
•Check the direction of your LEDs!
Did you solder them on in the proper
orientation? If you need to change
the direction of an LED, you can do
this without damaging the LED if
you're careful. Put your soldering
iron to the side of the LED and add a
bunch of solder until it blobs and
touches both ends of the LED, and
gently wipe the LED right off the
board. If your LED is still on the
solder blob on the tip of your iron,
immediately whack the palm of your
hand holding the iron against the
table. This will cause the solder and
the LED to drop off the tip, onto your
table. Gently wipe most of the
excess off of your LED and try again!
We also give you an extra LED.
All of the LEDs don't light up:
•Check the direction of your LEDs per
above.
•Check the direction of your battery.
•Check the direction of your 555
timer chips.
•Check the direction of your mini-
MELF diodes.
The LEDs blink, but in a weird/wrong
pattern:
•First, take your battery out and make
sure your circuit board is clean, per
the above step. Try it again. If it still
is weird, go onto the following steps.
•The first one minute may in fact have
a slightly different pattern, there can
be a small "break-in" period. (It's an
interesting effect due the initial
voltage & internal resistance of a
fresh battery). Just wait and see if it
changes.
•Check the direction of your timer
chips and mini-MELF diodes.
Check your resistors for the correct
values in the correct places. You can
look at the numbers written on top
under magnification, and you can
also turn the circuit OFF, and
measure each one's resistance with a
multi-meter.
•Check your capacitors for the correct
values in the correct places. The two
most important ones are the 2.2uF
C4 and the 10uF C1. There's a
difference in the sizes of those
capacitors, C1 should be the
biggest/tallest one on the board. C4
should be the second biggest.
Double-check the assembly drawing.
You can also measure the
capacitance in-circuit if you have a
multimeter, but note you'll get
slightly different values than "ideal"
out-of-circuit values. You should still
be able to verify that they're in the
correct positions.
