Troubleshooting
T
o Troubleshoot
aY
OLoop
Unlocked Condition
-
General
Procedure
1.
If the
error number
received
is
for
an
LO
synthesizer
Unlocked
error
(33
=
4,
33 =
20,
etc
.) go
to the
procedure
\LO
Synthesizer
and
Reference
Assembly
(A6)
Troubleshooting"
in
this chapter
.If
the
error
number
received
is
for
a
\Y
O
Loop
unlocked
at
XXX
GHz" error
(33
=2,
33 =
10,
etc
.)
go
to
step
5,
otherwise
,
continue
with
the
next
step.
2.
Set
the
output
frequency
of
the
synthesizer
to
1
GHz.
3.
Set
the
oset
synthesizer
frequency
of
the
synthesizer
to
the
frequency
shown
in
the
error
message
received
(14.749
MHz
if
the
error
message
received
is
32
=
10,
etc
.).
F
or
example
,
to
set
the
oset
synthesizer
frequency
to
14.749
MHz:
a.
Press
4
SPCL
5
.
b.
Press
4
63
5
on
the
numeric
keypad,
then
terminate
the
entry
by
pressing
4
Hz
5
(ENTER).
c.
Press
4
14.749
5
on
the
numeric
keypad.
d.
Press
4
MHz
5
to
complete
the
entry
.
4.
Go
to
step
6
to
continue
.
5.
Set
the
output
frequency
of
the
synthesizer
to
the
frequency
shown
in
the
error
message
received
(2.385
GHz
if
the
error
message
received
is
33
=
2,
etc
.).
6.
Clear
any
unlock
condition.
When
the
frequency
is
changed,
an
undesirable
unlock
condition
can
occur
momentarily
.
a.
Press
4
SPCL
5
.
b.
Press
4
60
5
on
the
numeric
keypad,
then
terminate
the
entry
by pressing
4
Hz
5
(ENTER).
c.
Press
4
74
5
on
the
numeric
keypad,
then
terminate
the
entry
by
pressing
4
Hz
5
(ENTER).
d.
Press
4
1
5
on
the
numeric
keypad,
then
terminate
the
entry
by
pressing
4
Hz
5
(ENTER).
7.
Connect
a
voltmeter
to J3
pin
2
on
the
Y
O
loop
and
oset
synthesizer
assembly
(A7)
(connect
the
voltmeter
ground
lead
to A3TP4).
8.
V
erify
that
the
voltage at
J3 pin
2
remains
at
a
TTL
low
level.
If
the
TTL
voltage
level
is
high,
continue
with
the
next
step.
If the
TTL
voltage
level
is
low
,
there
is
no
trouble
found
in
the
Y
O
loop
and oset
synthesizer assembly
or
anywhere
else
in
the
Y
O
loop
.
9.
Open the
connection
between
the
Y
O
loop
and
oset
synthesizer
assembly
and
the
YIG
Driver
assembly using
the
following
steps:
a.
Press
4
SPCL
5
.
b.
Press
4
60
5
on the
numeric keypad,
then
terminate
the
entry
by
pressing
4
Hz
5
(ENTER).
c.
Press
4
57
5
on
the
numeric
keypad,
then
terminate
the
entry
by
pressing
4
Hz
5
(ENTER).
d.
Press
4
98
5
on
the
numeric
keypad,
then
terminate
the
entry
by
pressing
4
Hz
5
(ENTER).
10. Disconnect W2 from J106 on the Y
O loop and
oset synthesizer assembly
.
11. Using a spectrum analyzer
, verify that the fundamental signal at
W2 is between 5 and 140
MHz and the power level is between
0
36 and +2 dBm. Also
check that all harmonics are
>
0
14 dBc
.
If the signal at W2 is correct, continue with step 14. If the signal is incorrect or missing,
continue with the next step
.
12. Disconnect W2 from the sampler (A8T1) IF OUTPUT.
13. Measure the signal at the sampler IF OUTPUT using the spectrum analyzer. The
fundamental signal should be between 5 and 140 MHz and the power level should be
between
0
36 and +2 dBm with all harmonics
>
0
14 dBc.
If the signal is correct, replace W2. If the signal is incorrect, continue with the next step.
1-36 Troubleshooting
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