back onto the board. Use the jewelers screwdriver if necessary. Once the pin is soldered and
the socket is seated remove the heat immediately. Allow the joint to cool.
5. Finally caref lly solder the remaining pins avoiding solder bridges between the pins and
adjacent traces.
6. Remove the cellophane tape and inspect the work j st completed. Give the board a final once
over looking for potential problems, solder shorts, nsoldered or badly soldered connections
etc.
7. Next install resistors. All resistors are installed on the board laying down with their leads p shed
thro gh the end holes and soldered on the back side of the board. R5, the 1K 1W resistor, may
be larger than the other resistors. See the Parts Placement diagram.
8. Install the capacitors. Be s re to properly orient the 2 electrolytic capacitors according to their
polarity. Radial lead electrolytic capacitors (both leads at one end of the capacitor) m st be
installed vertically. The negative leads on the electrolytic capacitors sho ld be mo nted facing
one another. The 102(0.001 f), 103 (0.01 f) and 104 (0.1 f) capacitors may look very similar.
Be s re not to interchange them.
9. Install Q1 the 2N3904, the LEDs and the p sh b tton (SW1). Be caref l to install the transistor in
the proper orientation and the LEDs in the proper direction. Sometimes the transistor pins will
need to be reformed to fit properly. The case of the transistor will be shaped to indicate the
part orientation. Note that the LEDs in kit may be ro nd (no flat spot). The short lead is
cathode (flat spot on silkscreen). The short lead sho ld be oriented near the edge of the board.
The longer lead m st be nearer the microcontroller socket. Be sure to install the correct color
LEDs in the correct positions. See the pict re regarding LED installation below. Orientation is
very important here. Improperly orienting the 2N 904 transistor can result in its destruction.
10. Install U1 the LM2950. It may be labeled KY5033. Orientation is very important here.
Improperly orienting the LM2950 integrated circuit can result in its destruction and the
destruction the LM2950 and of the microcontroller.
11. Install Q2 the ZVP4424A. Orientation is very important here. Improperly orienting the
ZVP4424A transistor can result in its destruction or reverse polarity protection failure.
12. Install yo r incl ded 2 screw terminal power connector and the 10-pin signal connector.
13. Install the speaker. It is not polarized so either direction will work fine.
14. Look over the board both top and bottom. Look for missing components, improperly oritnted
components, cold or dry solder connections, solder blobs and splashes. Do ble check the
position and orientation of each component.
