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(6)
(7)
(8)
(1)
(a)
Check
the microcomputer data output line
(U400, pins 28, 29) conditions
with
an oscillo-
scope:
e
Condition
1
-
With the radio
in
the standby
mode, there should be no data activity.
e
Condition
2
-
When the volume control,
frequency switch,
PTT
switch, or monitor
button is
actuated, there should be data
activity.
(ob)
The DATA
output
lines
from
U400
control the
microprocessor interface
units
in
U101 (pin
31), U700
(pin 11), and
U200
(pin
23),
and
channel
information to
U300
(pin
30).
If
any of
these devices
is
defective,
it
could
hold the
DATA
line
inactive.
1.
Check
the dc
level
of
each
of
these
devices.
2.
Make sure that the
2.1
MHz signal
from
U300
(pin 17) is correct.
3.
Make sure that there is data activity at
U400,
pin 11, during
volume adjustment,
channel changing, and pressing
of the
PTT
and monitor switches.
Check
the voltage references of microcomputer
U400
(pin
63 = OVdc and
OQ
to ground; pin
64 =
5Vdc).
NOTE
These
two
voltage
points on
U400 set
up an inter-
nal
voltage reference table
within the microcomput-
er.
If
the
voltages are
incorrect, certain functions of
the radio may operate erratically;
for
example,
monitor,
volume, ete.
Check
the transmit
5Vde
line
(U201,
pin 11).
Ensure
that there is no
dc level
with
the radio
in
the standby mode.
If
a dc level is present, this
may indicate
a
microcomputer lockup condition.
Another lockup condition may be present
if
all
checks seem
normal, but the radio still
fails
to
communicate
with the
PC.
If
this is the
case,
then
perform
steps (a)
and (b):
(a) Turn the radio off and ground
pin 3 of
J4.
Then, while pressing the
PTT
switch,
turn on
the radio.
Remove
the ground and
release the
PTT
switch.
(b) With the radio
in
this condition, program the
radio.
If
the radio
will not program,
go
to
step
b
(2) (a) 2.
Radio Will
Not
Keyload
(SECURENET
radios only)
Verify that the correct keyloader is being used
for
the particular type of encryption present
in
the
radio.
Refer
to
the following chart:
(2)
(3)
(2)
(3)
(4)
Replace
the
SECURENET
module,
U900,
with
a
test module having the same
kit number.
If
the
problem
persists, continue troubleshooting.
(a)
Check
that U900, pin 9,
=5Vdc.
(b)
Check
that
U900, pins 15 and 18, =7.5Vdc.
(c) Verify
that activity is present on pins
6 and
11
of
U900 when
the radio is turned on.
(d)
Check
that the
KEYLOAD
line
(U900,
pin
5)
goes
low when the
keyloader cable
is
attached to the radio's universal connector.
If
it
does
not
go
low,
suspect a
bad
cable
or an
open between
pin 10 of the
universal connec-
tor and pin
5
of
U900.
(e)
Check
that the
WRITE ENABLE
line
(U900,
pin
7) momentarily
goes
low while attempting
to load
a
key.
If it
does
not
go
low,
suspect
an
open between pin 5 of the universal connector
and
pin
7 of U900.
(f)
Check
that there is data applied
to
the
KEY/FAIL
line
(U900,
pin 16) while attempting
to load
a
key.
If
no
data is applied, suspect an
open between
pin
9 of the universal connector
and
pin 16 of
U900.
Check
that there is data applied to the
KEY
INSERT
DATA (KID)
line
(U900,
pin
4) while
attempting to load
a
key.
If
no
data is applied,
suspect
an open between
pin
11
of the univer-
sal connector and
pin
4
of
U900.
d.
Standby Current
(1) Verify that the radio has
a
good checksum, and is
squelched.
If
the standby current is consistently
high
(>80 mA), replace
the
rf
PA
module, U202.
If
the current is
still
bad, replace the remaining mod-
ules, one at a
time, with test modules.
Make a visual check
of the main circuit board.
Ensure
that all tantalum
capacitors are placed cor-
rectly (proper polarity).
Check
for
solder bridges.
Check
the transmit
5Vdc
line
(U201,
pin
11).
Ensure
that there is no
voltage
with
the radio
in
the standby mode.
NOTE
Both number
1
and
number
2 regulators
must be
operational for the microcomputer
(U400)
to
func-
tion properly.
Check
that the
voltage at the collector
of number
1
regulator
Q1
=
5Vdc.
If
the voltage is lower than
4.8Vde
or higher than
5.2Vdc,
then complete this
step:
(a)
Check
that the
resistance
of Q1
collector to
ground
approximately
4kQ (negative side
of
the probe connected
to
ground).
(bo)
Check
the
bias levels
of
Q1:
emitter
= 7.5Vde;
base = 6.7Vdc.
If
the levels are wrong,
sus-
pect the
i-f
IC, U100.
(9)
U900
Keyloader
Kit
No.
Kit
No.
NTN4711/NTN5832
T3010
DVP
NTN4713/NTN5834
T3014
DVP-XL
NTN4715/NTN5836
T3012
DVI-XL
Description
23
(6)
(7)
(8)
(1)
(a)
Check
the microcomputer data output line
(U400, pins 28, 29) conditions
with
an oscillo-
scope:
e
Condition
1
-
With the radio
in
the standby
mode, there should be no data activity.
e
Condition
2
-
When the volume control,
frequency switch,
PTT
switch, or monitor
button is
actuated, there should be data
activity.
(ob)
The DATA
output
lines
from
U400
control the
microprocessor interface
units
in
U101 (pin
31), U700
(pin 11), and
U200
(pin
23),
and
channel
information to
U300
(pin
30).
If
any of
these devices
is
defective,
it
could
hold the
DATA
line
inactive.
1.
Check
the dc
level
of
each
of
these
devices.
2.
Make sure that the
2.1
MHz signal
from
U300
(pin 17) is correct.
3.
Make sure that there is data activity at
U400,
pin 11, during
volume adjustment,
channel changing, and pressing
of the
PTT
and monitor switches.
Check
the voltage references of microcomputer
U400
(pin
63 = OVdc and
OQ
to ground; pin
64 =
5Vdc).
NOTE
These
two
voltage
points on
U400 set
up an inter-
nal
voltage reference table
within the microcomput-
er.
If
the
voltages are
incorrect, certain functions of
the radio may operate erratically;
for
example,
monitor,
volume, ete.
Check
the transmit
5Vde
line
(U201,
pin 11).
Ensure
that there is no
dc level
with
the radio
in
the standby mode.
If
a dc level is present, this
may indicate
a
microcomputer lockup condition.
Another lockup condition may be present
if
all
checks seem
normal, but the radio still
fails
to
communicate
with the
PC.
If
this is the
case,
then
perform
steps (a)
and (b):
(a) Turn the radio off and ground
pin 3 of
J4.
Then, while pressing the
PTT
switch,
turn on
the radio.
Remove
the ground and
release the
PTT
switch.
(b) With the radio
in
this condition, program the
radio.
If
the radio
will not program,
go
to
step
b
(2) (a) 2.
Radio Will
Not
Keyload
(SECURENET
radios only)
Verify that the correct keyloader is being used
for
the particular type of encryption present
in
the
radio.
Refer
to
the following chart:
(2)
(3)
(2)
(3)
(4)
Replace
the
SECURENET
module,
U900,
with
a
test module having the same
kit number.
If
the
problem
persists, continue troubleshooting.
(a)
Check
that U900, pin 9,
=5Vdc.
(b)
Check
that
U900, pins 15 and 18, =7.5Vdc.
(c) Verify
that activity is present on pins
6 and
11
of
U900 when
the radio is turned on.
(d)
Check
that the
KEYLOAD
line
(U900,
pin
5)
goes
low when the
keyloader cable
is
attached to the radio's universal connector.
If
it
does
not
go
low,
suspect a
bad
cable
or an
open between
pin 10 of the
universal connec-
tor and pin
5
of
U900.
(e)
Check
that the
WRITE ENABLE
line
(U900,
pin
7) momentarily
goes
low while attempting
to load
a
key.
If it
does
not
go
low,
suspect
an
open between pin 5 of the universal connector
and
pin
7 of U900.
(f)
Check
that there is data applied
to
the
KEY/FAIL
line
(U900,
pin 16) while attempting
to load
a
key.
If
no
data is applied, suspect an
open between
pin
9 of the universal connector
and
pin 16 of
U900.
Check
that there is data applied to the
KEY
INSERT
DATA (KID)
line
(U900,
pin
4) while
attempting to load
a
key.
If
no
data is applied,
suspect
an open between
pin
11
of the univer-
sal connector and
pin
4
of
U900.
d.
Standby Current
(1) Verify that the radio has
a
good checksum, and is
squelched.
If
the standby current is consistently
high
(>80 mA), replace
the
rf
PA
module, U202.
If
the current is
still
bad, replace the remaining mod-
ules, one at a
time, with test modules.
Make a visual check
of the main circuit board.
Ensure
that all tantalum
capacitors are placed cor-
rectly (proper polarity).
Check
for
solder bridges.
Check
the transmit
5Vdc
line
(U201,
pin
11).
Ensure
that there is no
voltage
with
the radio
in
the standby mode.
NOTE
Both number
1
and
number
2 regulators
must be
operational for the microcomputer
(U400)
to
func-
tion properly.
Check
that the
voltage at the collector
of number
1
regulator
Q1
=
5Vdc.
If
the voltage is lower than
4.8Vde
or higher than
5.2Vdc,
then complete this
step:
(a)
Check
that the
resistance
of Q1
collector to
ground
approximately
4kQ (negative side
of
the probe connected
to
ground).
(bo)
Check
the
bias levels
of
Q1:
emitter
= 7.5Vde;
base = 6.7Vdc.
If
the levels are wrong,
sus-
pect the
i-f
IC, U100.
(9)
U900
Keyloader
Kit
No.
Kit
No.
NTN4711/NTN5832
T3010
DVP
NTN4713/NTN5834
T3014
DVP-XL
NTN4715/NTN5836
T3012
DVI-XL
Description
23
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