39
U202
74HC139
U203
74HC240
U204
ULN2803A
(12) Install the 7805 5-Volt regulator at U205. Bend the leads on the 7805 to align with
the pads on the circuit board. The body of the IC should sit about 1/4” above the circuit
board.
The 7805 voltage regulator is vertically mounted and sits about 1/4”
above the circuit board.
(13) Plug the Basic Stamp BS2-IC into the socket previously installed at U201. (Wear a
wrist strap or touch a ground while you handle this component.) Make certain the BS2-IC
is aligned with the notch on the silkscreened legend, and verify that all 24 pins are
properly seated into the socket. Take your time nursing the BS2-IC into its socket and do
not apply excessive pressure. It helps to rock the BS2-IC back and forth slightly while
you insert it.
Verify that its pins are straight before inserting the BS2-IC into its
socket.The white dot on the front of the BS2-IC must be aligned with
the notch on the silkscreening.
(14) Clean the flux from the bottom of the circuit board with isopropyl alcohol and Q-
tips and then inspect each solder joint using a magnifying glass. Look especially closely
at the multipin connectors along the rear edge of the circuit board, the 26 pin header, and
the pins on the ICs.
(15) With a pair of wire cutters, cut a 1/8” notch at the
right rear corner
of the circuit
board. Note that the outline of the notch is silkscreened on the board. The notch allows
the circuit board to clear the side bracket on the enclosure.
Use wire cutters to cut a 1/8 in. notch in the right rear corner of the
microcontroller circuit board.
