Q40. Tx Output Power Has Dropped Just In 8M; Q42. During Checking For Tx Power Output, The Power Supply Turned Off And The System Started With A Message Saying "Initializing; Q43. Tune Ng Occurred. I Would Like To Know The Procedure - Furuno FS-1575 Service Manual

Q40. TX output power has dropped just in 8M. Which board has a trouble that
resulted in the drop in output power?
A40. If TX output power on a specific band has dropped, this resulted from a trouble
with the TX FIL board. In this case, you should focus on the filter switching
frequency of the TX FIL board.
To make a general examination on the trouble, you should select [MENU] -> 1.
TEST -> 2.TX SELF TEST and conduct self-tests. To make further examination
on it, you should select [MENU] -> 9.SERVICE -> 3.RT SETUP ->
2.SELF CHECK and conduct self-checks. If any abnormal values are detected as
a result of them, these values will be displayed in "red."
Q41. During the adjustment of TX output power, the system stopped outputting
power and displayed an error message saying "Communication error!."
A41. Supposed causes and measures:
You should reduce the TX power output to check for the output conditions. If OK,
there may be RF interference in the data line between the Control unit and the
Transceiver unit.
Have you grounded the Transceiver unit and the Control unit? Have you
connected the shielded wires of the signal cable between these units to the
housing? Please add EMI cores to cables between the units. If only small EMI
cores are available, please add them to the DATA-A and –B lines. Furthermore,
make twist the each pair wires.
Q42. During checking for TX power output, the power supply turned OFF and the
system started with a message saying "Initializing..." again.
A42. You should try to take the same measures as those described in Q41.
Q43. TUNE NG occurred. I would like to know the procedure for taking measures
against the TUNE NG problem.
A43. You should follow the procedure shown below:
・ Check for the connections of antenna lead-in wire and grounding ATU.
・ Check for the connections of coaxial cable and connectors connected to the
ATU.
・ Check for any burnout in the ATU.
・ Check for TX output power. TX output power ranges from 10W to15W for
tuning. The system initiates tuning even at several watts.
・ Conduct self-tests on the ATU and TX self-tests.
・ If TUNE NG occurs on a specific band, check for TX output power on the
relevant band.
・ If TUNE NG occurs on a specific band, change the antenna length.
Add a cable of several meters in length to the ATU, and then check for TX
output power. If output power is OK, TUNE NG has resulted from extremely
high or low antenna impedance, or ATU failure.
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9-7
Chapter 9 Q&A
See page 6-59