Price - Stock No 170
- Make a visual check of the P.C.Board to
ensure no damage has happened in transit. Continuity of the tracks can
be checked with a multimeter or an electronic
Circuit Tester. Any breaks can be bridged with solder.
- Identify the resistors either by their colour bands, or
with a multimeter see Resistors. Bend the legs to match
their holes and assemble them.
- Solder in place - see Soldering
- There are two 0.1uF and one 0.01uF capacitors
see Capacitors. Mount the capacitors in their correct
positions and solder in place.
- Insert the 47 uF capacitor - be sure to observe the
- Nine pins are in the kit. These are soldered into
the four AM Coil connection points, one antenna point, two for
the battery points and two for the jack socket.
- Insert the tuning capacitor and solder.
- The BC 548 and the MK 484 must be insert in
the correct orientation. The component and PCB diagrams above will
assist. Caution should be exercised when soldering these
components. Excess heat may damage these components however, sufficient
heat from your soldering iron should be applied to make sound connections.
- Solder the jack socket to it's PCB pins.
- Connect the battery holder - Black to 0 V, Red to + 1.5
- Take the hook up wire and tin one end - refer Tinning
wire. Connect the antenna to its PCB pin.
- Connect the four leads of the AM Coil. These are
colour coded and caution should be taken to identify and correctly connect
- Your AM radio is now complete and ready for a battery, an
earpeace and testing.
Circuit description and tuning
The heart of this circuit is the MK 484. It
is a purpose built AM radio. The radio station is tuned with the variable
capacitor, which in conjunction with the inductor isolates a frequency on the AM
radio spectrum. The information (talking / music) on this frequency
is delivered to the MK 484 at it's input - leg 2. The output, which is
quite low level is then coupled (via a capacitor) to the base of the BC
548. The BC 548 amplifies the information to a level that can be heard
through an earpiece.
If the AM Radio doesn't work check the
- The BC 548 ank MK 484 are inserted
- The five resistor values are as the diagram shows.
- The 47uF capacitor is in the correct
- The inductor and battery wires are connected
- Check all soldering. Re-solder
any joints that look suspicious, making sure that the solder takes to the
track as well as to the legs.
- The battery is not flat.
Contact CdS electronics