Elenco LIGHT - Manual (Page 15)

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Advanced Troubleshooting
(Adult supervision recommended)
ELENCO ® is not responsible for parts
damaged due to incorrect wiring.
If you suspect you have damaged parts,
you can follow this procedure to
systematically determine which ones need
replacing:
(Note: Some of these tests connect an LED
directly across the batteries without another
component to limit the current. Normally this
might damage the LED, however Snap Circuits
®
LEDs have internal resistors added to protect
them from incorrect wiring, and will not be
damaged.)
1. Red LED (D1), motor (M1), speaker (SP),
and battery holder (B1):
Place batteries in
holder. Place the red LED directly across the
battery holder (LED + to battery +), it should
light. Do the same for the motor, it should
spin. “Tap” the speaker across the battery
holder contacts, you should hear static as it
touches. If none work, then replace your
batteries and repeat. If still bad, then the
battery holder is damaged.
If the motor spins but does not balance the
fan, check the black plastic piece with three
prongs on the motor shaft, and replace it if
it is damaged (this kit includes a spare). To
replace, pry the broken one off the motor
shaft using a screwdriver, then push the new
one on.
2. Red & black jumper wires: Use this mini-
circuit to test each jumper wire, the LED
should light.
3. Snap wires: Use this mini-circuit to test
each of the snap wires, one at a time. The
LED should light.
4. Slide switch (S1) and Press switch (S2):
Use this mini-circuit; if the LED doesn’t light
then the slide switch is bad. Replace the
slide switch
with the press
switch to test it.
5. 100 Ω (R1) and 5.1k Ω (R3) resistors: Use
the mini-circuit from test 4 but replace the
switch with the 100
Ω resistor (R1); the LED
will be bright if the resistor is good. Next use
the 5.1k
Ω resistor in place of the 100 Ω
resistor; the LED should be much dimmer
but still light.
6. White LED (D6) and color LED (D8): Use
this mini circuit; if the white LED doesn’t light
then D6 is bad. Replace the white LED with
the color LED; it should change colors in a
repetitive pattern, otherwise D8 is bad.
7. Microphone (X1) and Phototransistor
(Q4):
Use the mini-circuit from test 6 but
replace the 100
Ω
resistor with the
microphone (+ on right); if blowing into the
microphone does not change the LED
brightness then X1 is bad. Replace the
microphone with the phototransistor (+ on
right). Waving your hand over the
phototransistor (changing the light that
shines on it) should change the brightness
of the LED or Q4 is bad.
8. Adjustable resistor (RV): Build project
160, but use the red LED (D1) in place of
the color LED (D8). Move the resistor control
lever to both sides. When set to each side,
one LED should be bright and the other off
(or very dim); otherwise RV is bad.
9. PNP transistor (Q1): Build the mini-circuit
shown here. The red LED (D1) should only
be on if the press switch (S2) is pressed. If
otherwise, then Q1 is damaged.
10. NPN transistor (Q2): Build the mini-
circuit shown here. The red LED (D1)
should only be on if the press switch (S2)
is pressed. If otherwise, then Q2 is
damaged.