Price - Stock No 250 - Fast Roll
Price - Stock No 251 - Slow Roll
Price - Stock No 252 - Variable Roll
- Make a visual check of the PC board for damage
in transit. Look for small breaks and/or other damage to tracks.
The copper tracks will have a green coating
on the tracks. This coating should be left in place as it protects the tracks
from oxidation or corrosion, and it does
not inhibit soldering in any way. A multi-meter or Electronic
Circuit Tester can be used to test continuity of the tracks.
- A Circuit Board Holder is
useful in freeing both hands for mounting and soldering the
components. A spring board clip can be
screwed down and will hold the board securely. Wooden
blocks with a suitable groove, and able to slide (say on two
pieces of dowel) to adjust to the varying lengths of PC
Board also work well. Commercially produced stands are
available, with an alternative magnifying glass. (types and prices available).
- Mounting the components is relatively
easy. The resistors will have to have the legs bent to match their
holes, and the greencap will fit in easily - any way round.They can be
soldered off as you go if you wish.
- The electrolytic capacitor is
polarised, so look on the body to find an arrow. This arrow points down
the -ve (K) leg. Check the drawing and put it in the right way
- To mount the push-button switch, push the two circuit
board pins into the holes where the switch goes. Solder them and
then push the legs of the switch down between the pins. Solder the
switch to the pins. This will give a solid mounting so the dice can be
attached to its box by the switch through a hole, with the nut on
top. The height of the flange of the switch will also give a
height to which the flanges of the LEDs can be adjusted before
soldering. The globe part of the LEDs will then push up through
your box and be supported in position by the switch. The
LEDs are also polarised. Find a small flat on the flange at
the base of the red dome. This flat is at the -ve(K)
leg. See the drawing for the correct
polarity of each LED.
- The 8 Pin & 16 Pin I.C. Sockets can be
soldered in carefully to make sure that no bridging occurrs between
legs. You will find that the legs of both the I.Cs are spread a little
wide to fit into their sockets. Take each I.C. and rest the
legs on a flat surface. Gently push
down so that row of legs is straightened a little. Repeat for the
other row of legs. Take the 555 Timer and find the locating mark on the
top surface and near or at one end. Check the drawing and push it into
its socket the right way round. The procedure for the 4017 is similar
but , because it can easily be destroyed by
static electricity, leave it in its antistat case until you have all other
components, switches, battery snap etc. in place and soldered
off. Finally, find the locating mark on the top
surface of the 4017, check its position with the drawing,
and push the IC into its socket.
- The dice is now ready for testing.
Connect a 9V battery, switch the slide switch
"on" and push the button. All LEDs will light up; release the button and
one will stay on. ( This is a purely random selection so there is
no way to "rig" the dice).
- If you want to experiment,try putting preferably sweaty
fingers at various places on the soldered joints with the slide switch
turned on. In some cases the
lights will "roll" on in sequence, slowly. This indicates that
changes to capacitance values and/or resistance values will
achieve a similar result.
View the Datasheet for the 4017.
View the Datasheet for the 555.
If the dice doesn't work then you will need to check all
polarities and ensure that all components are in correct places.
Check soldering and resolder any suspect joints.
It will help if a general understanding of the circuit is acquired.
Briefly , when the PB switch is depressed a pulse is generated by
the 555 IC (Timer). This pulse is conducted to the 4017 IC
(Decade Counter) which acts as a rotary switch. In this case only six of
the IC's pins are used to distribute the
pulse to the LEDs in turn. The next pin in order is connected
to the reset pin of the IC. This restarts the switching action
to maintain an automatically resetting switching process. This all happens
very quickly, so fast that all LEDs appear to light up when the push button is
pressed. The system equates roughly with the spark distribution
system of a motor car engine , where the pulse at the
distributor points (or their substitute) generates a
high voltage at the coil , which is distributed to the spark plugs by the
rotor in the distributor - a rotary
switching mechanism. The
alpha-numeric grid locations on the placement sheet are used in this
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