Pa Board: 05P0868 (Fs-1575) - Furuno FS-1575 Service Manual

4. PA board: 05P0868 (FS-1575)

Like the DRV board, the PA board has a built-in V-SWR detection circuit to output the
VF and VR signals from the "J1". Making measurement of these signal levels allows for
determining whether the PA board outputs power.
In addition, making measurement of the base bias voltage of the PA transistor allows for
making acceptance judgment of the PA transistor and the bias circuit.
PA
J5 J2
TX
RF
RF IN
VR PA
CHK PA
Fig. 6.11.9 FS-1575 - PA Board Block Diagram
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.
Q2
Q1
T1
Q1
ATT
Q3
BIAS
BIAS
6-81
Collector: 42VDC
Emitter: RF GND
Q2 Q4
T2
T
Q5
15V BIAS 24V
6.11 Level Check
Emitter: RF GND
Base: 0.68VDC
RF OUT
T6
DET
Vf/Vr