Specifications

Phase-lock Loop
Problem
If the MS462XX detects a Phase-lock loop problem during normal opera
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tion, an error code followed by a brief error message will be displayed on
the screen. The error code will also be written to the service log along
with some of the operating data gathered from the system at the time of
failure. Possible causes include:
q
10 MHz Reference Signal missing
q
Internal VCO of Source Module failure
q
Faulty communication to the Source Module
q
Power Supply failure
Troubleshooting tools include:
q
Service Log: Error codes are written to the service log along with
data representing system conditions at the time of failure.
q
Phase-lock Error Codes: Phase-lock error codes have an alphabet
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ical suffix (code) following the message. This suffix code consists
of one or more letters from A to F or from J to L that represent
the portion of the source circuits that were not locked. The
Phase-lock failure mode suffix codes are listed in the table below:
Suffix Failure Mode
A Source 1 DDS Clock Lock Fail
B HET Lock Fail
C LO Offset Lock Fail
D Source 1 Offset Lock Fail
E LO Main Lock Fail
F Source 1 Main Lock Fail
J Source 2 DDS Clock Lock Fail
K Source 2 Offset Lock Fail
L Source 2 Main Lock Fail
Depending on the nature of the failures and the frequency band when the
failure occurred, more than one failure suffix may be displayed. Suffixes
do not necessarily appear in alphabetical order.
Examples:
6100 PHS LCK FAIL FCBALJ
6100 PHS LCK FAIL CBALJ
Both example error messages were caused by the absence of the 10 MHz
Reference Time Base Signal. The first message occurred when the instru
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ment was sweeping from 820 MHz to 850 MHz. The second message oc
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curred when the instrument was sweeping from 10 MHz to 6 GHz.
6-10 MS462XX MM
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