Tx Tune (On, Off) - Furuno FS-1575 Service Manual

8. TX TUNE (ON, OFF)

This Submenu-3 is used to select whether or not to transmit a TUNE start signal to
AT-5075/AT-1575 when transmitting.
Setting TX TUNE to "ON" will start the TUNE operation with "TX KEY" is activated,
"PTT" to "ON" , and press and hold the [0:TUNE] key.
Reference)
1) Even if the tuning operation fails, TX output power will be automatically reduced.
• FS-5075: LOW2
• FS-2575/1575: LOW
2) If the tuning operation fails, the matching circuit of the Antenna coupler will go
into a through state.
Note)
The term "through state" means that all coils (L) in the matching circuit are in a
short-circuited state and input/output capacitors (C) in the matching circuit are in
an open state.
3) To check the FS-xx75T system for TX output power by connecting a dummy load
load,
• set TX TUNE to "OFF," and no tuning signal will be outputted, and
• connect between #7 (TUNE OK) and #9 (TUNE) of TB6 on the T-IF board using
a jumper wire, and the matching circuit will be constantly kept in the "TUNE
OK" state.
CONFIDENTIAL (internal use only)
This confidential document is used only by FURUNO authorized persons.
It is strictly prohibited to reproduce the document in whole or in part without prior written permission of FURUNO.
Connect a jumper cable
between #7-#9 of TB6
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4.7 SERVICE