Pa Board: Pa Vc Check Meter Reading Adjustment - Furuno FS-1575 Service Manual

2. Disconnect the [J1: TX OUT] connector from the TX board.
3. Turn ON the power supply, and then press the PTT on the handset to put the system
into a TX state.
4. Make adjustment of the PA BIAS variable resistor so that PA BIAS current (i.e., DC
ammeter reading) will come to a specified BIAS current.
• FS-2575 and FS-5075:
Adjust R51 to 400 mA (for TP3 - TP4 40-mV line) and 500 mA (for 42 V line).
• FS-1575:
Adjust R75 to 400 mA (for 24V line).
2. PA Board: PA Vc check meter reading adjustment (FS-1575, -2575, -5075)
Procedure)
Select [MENU] -> 9.SERVICE -> 3.RT SETUP -> 4.TX POWER (FREQ) to open
1.
the "TX POWER (FREQ)" window.
PA2 VC
Make measurement of voltage between the Collector and Emitter of the PA
2.
transistors.
• FS-2575 and FS-5075:
• FS-1575:
Make adjustment of the Vc reading adjusting variable resistor so that the reading
3.
will come to the voltage measured.
FS-5075 has two PA boards. Make the above adjustment for each PA board.
• FS-2575 and FS-5075:
• FS-1575:
Reference)
VC reading displayed on the "RT SETUP" window of the FS-5075 is "VC1."
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.
Q1 and Q2
Q4 and Q5
R47
R85
5-36
5.7 Board Adjustment
Appears in case of FS-5075
PA2 VC