-8-
TESTING YOUR LOGIC PULSER
Checking out your Logic Pulser for proper operation
is fairly easy. All that is needed is a 9V battery or
other DC power source (5-10V). Connect the red
alligator clip to the positive terminal of the battery
and the black clip to the negative terminal.
Set the pulse repetition rate switch to the 0.5PPS
position. Check the red LED. It should blink once
every 2 seconds (0.5PPS).
Set the switch to
400PPS. The Logic Pulser generates a frequency
of 400Hz. At this frequency, the LED flashes at a
rate that makes it appear to be on continuously. If
either of these tests fail:
a) Check the input cable. The ribbed wire with the
red alligator clip should go to the hole marked
(+).
b) Check for cold solder joints and solder bridges
around the IC. Check that the IC notch matches
the notch shown on the PC board.
c) Check the soldering and polarity of diodes D1,
D2, D3 and D6 (LED).
d) Check that transistor Q5 is the correct type and
is mounted with the flat side as shown on the PC
board.
e) Check the soldering and the values of capacitors
C1 through C5.
f) Check the soldering and the values of resistors
R1 through R5 and R15 through R17.
If you have an oscilloscope, connect it to the Square
(SQ) Pin and observe the waveforms shown in
Figure 12 for pulse repetition rate switch settings of
400PPS and .5PPS.
The times shown are
approximate. If you do not get these waveforms:
a) Check the value and soldering of R16.
b) Check that transistor Q5 is the correct type and
is mounted with the flat as shown on the PC
board.
c) Check the value and soldering of capacitors C3,
C4 and C5.
Connect the pulser tip to the resistor combinations
shown in Figure 12 and observe the waveforms
shown for the pulser tip. If you do not get these
waveforms:
a) Check that transistors Q1 through Q4 are the
correct type and are mounted with the flat side
as shown on the PC board.
b) Check the soldering and polarity of diodes D4
and D5.
c) Check the soldering and values of resistors R7
through R14.
d) Check the soldering and values of capacitors C3
through C8.
Figure 12
