Drv Board: 05P0866A, B (Fs-5075, -2575) - Furuno FS-1575 Service Manual

2. DRV board: 05P0866A, B (FS-5075, -2575)

The DRV board has a built-in V-SWR detection circuit to output "Vf: CHK DA (J1-#5)
and "Vr: VR DA (J1-#7)" signals.
Making measurement of these signal levels allows for determining whether the DRV
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 PA
bias circuit.
To make measurement of bias voltage, disconnect the "J2: RF IN" from the DRV board.
The RF ground of the PA transistor is different from the ground of housing. For this
reason, be sure to make measurement between the bias voltage and the RF ground.
Collector: 24VDC
Emitter: RF GND
Q4, 5: SD1407
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.
Q4
Q5
Emitter: RF GND
Base: 0.67 VDC
6-75
Q2
Q1
Q3
Gate: 4.38 VDC
Source: 0 VDC
Drain: 15.0 VDC
Source: 0 VDC
Drain: 15.0 VDC
6.11 Level Check
Example: FS-2575
@4M, +5dBm input,
Output; 10W
Q2 、３ : RD16HHF1_101
Gate: 3.63 VDC