Elenco Snap Circuits SOUND &reg - Manual (Page 17)

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. Color LED (D8), speaker (SP2), and
battery holder (B1):
Place batteries in
holder. Place the color LED directly across
the battery holder (LED + to battery +), it
should light and be changing colors. “Tap”
the speaker across the battery holder
contacts; you should hear static as it
touches. If neither works, then replace
your batteries and repeat. If still bad, then
the battery holder is damaged. Test both
battery holders.
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 W (R1) and 5.1k W (R3) resistors, and
microphone (X1): Use this mini-circuit;
the LED will be bright if the R1 resistor is
good. Next use the 5.1k
W resistor in place
of the 100 W resistor; the LED should be
much dimmer but still light. Next, replace
5.1k
W resistor with the microphone (“+” to
right); the LED should flicker dimly but still
light.
6. 500k W adjustable resistor (RV3) and
Photoresistor (RP): Use the mini-circuit
from test 5 but replace the 100 W resistor
with RV3. Turning RV3’s knob all the way
to the left (counter-clockwise) should make
the color LED bright and most other
settings should make the LED dim or off;
otherwise RV3 is bad. Next, replace RV3
with the photoresistor, and shine a bright
light on it. Waving your hand over the
phototransistor (changing the light that
shines on it) should change the brightness
of the color LED; otherwise the
photoresistor is bad.
7. Adjustable resistor (RV): Build project
98. Move the resistor control lever to both
sides. The color LED (D8) should be bright
if the lever is to the far left or far right, and
dim if the lever is in the middle.
8. NPN transistor (Q2): Build the mini-
circuit shown here. The color LED (D8)
should only be on if the press switch (S2)
is pressed. If otherwise, then Q2 is
damaged.
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