Appendix A – Test Procedures
a. Measurements
Disconnect
the
tracker,
remove
U1
from
its
socket,
and
use
an
ohmmeter
to
check
the
following
connections.
Nominal
values
are
approximate.
Connection
Nominal
Value
Circuit
Description
U1
‐
1
to
U1
‐
16
2.6
k
Ω
Power
to
Ground
U1
‐
9
to
U1
‐
10
10
M
Ω
Crystal
oscillator
R8
outer
leads
10
k
Ω
TX
level
adjust
pot
JP2
to
JP8
30
k
Ω
Voltage
divider
U1
‐
5
to
U1
‐
1
7.5
k
Ω
Temperature
sensor
With
U1
removed,
connect
the
tracker
to
its
power
source.
Using
U1
pin
1
or
JP2
as
ground,
check
the
following
voltages.
Connection
Nominal
Value
Circuit
Description
U1
pin
16
5
V
±
0.25
Voltage
regulator
output
U1
pin
5
10
mV
/
K
Temperature
sensor:
2.95
V
=
295
Kelvin
=
71.3
°F
JP8
6.7
to
35
V
V
in
U1
pin
6
1/3
V
in
Voltage
divider
Remove
power,
re
‐
install
U1,
and
power
up
the
tracker.
With
a
typical
digital
voltmeter,
U1
pins
9
and
10
should
indicate
approximately
2.4
V
and
2.2
V,
respectively.
A
frequency
counter
or
oscilloscope
should
show
a
29.4912
MHz
signal
at
these
pins.
Absence
of
this
signal
indicates
a
problem
with
U1
or
the
crystal
oscillator.
OpenTracker Manual - Version 1.05 – 6/25/06
page
20
of
23
