Initial Test -- 1
Preliminaries
Errors take two forms, the kind that damage components and the kind that don't. Neither is desirable, but the
type that damages components will require you to find a replacement part. Before connecting the board for
the first time, check the following:
Ok
Procedure
Polarity of the electrolytic capacitor. The negative lead is usually identified with a white
stripe and a big minus sign on it. The positive lead is identified on the PC board.
Polarity of the four tantalum capacitors. The positive lead is usually identified with a
red line and plus signs.
Polarity of diode D1. The band on the diode should align with the extra stripe on the PC
board silkscreen.
The orientation of the integrated circuits with pin 1 correctly oriented to the dot, notch
or bevel outline on the PC board.
Be Alert!
Observe anything unusual such as components heating up, smoke or smell. If anything unusual
appears, immediately turn off the power. Find and correct all problems before continuing.
Ok
Procedure
Place the ground lead of your meter on the anode (opposite the banded end) of D1. This
is ground reference for all measurements.
With the meter set to read ohms, check pins 1 and 3 of IC8. These may show a low
resistance initially because of charging effects, but after a few seconds the resistance at
pin 1 should be greater than 10kohms, and at pin 3 greater than 500 ohms. If either
shows a very low resistance, check your work for short circuits.
Integrated Circuit Installation -- 1
Integrated circuits are polarity sensitive devices. The small notch in the body is on the end with pins 1 and 8.
Make sure the notch on the component matches the one on the silkscreen!
Ok
Procedure
Install a 7809 voltage regulator IC at IC8. The regulator can be mounted either flat on
the board, or standing vertically, depending on the space available in your
configuration. The heat sink tab should face the bottom or the back of the board.
Solder and clip 3 leads.
