Home
>
MFJ Enterprises
>
Communications receiver
>
MFJ Enterprises 9475 Hf Transceiver Instruction Manual
MFJ Enterprises 9475 Hf Transceiver Instruction Manual
Have a look at the manual MFJ Enterprises 9475 Hf Transceiver Instruction Manual online for free. It’s possible to download the document as PDF or print. UserManuals.tech offer 4 MFJ Enterprises manuals and user’s guides for free. Share the user manual or guide on Facebook, Twitter or Google+.
![Page 10
MFJ-9475 Instruction Manual 75-Meter SSB Travel Radio
10 Receiver Sensitivity: (Use a calibrated RF-Signal Generator)
[ ] Connect a weak 3.900 signal source to ANTENNA
jack.
[ ] Tune in source for maximum S-meter reading using VFO.
[ ] Adjust Signal Generator amplitude for S5-S7 meter reading.
[ ] Touch up L1, L2, T1, T2 for maximum S-meter reading.
Transmitter Bandpass Filter Alignment: (Use a Watt meter and Dummy Load)
[ ] Connect low-power watt meter with dummy-load to the...](http://img.usermanuals.tech/thumb/5701/82932/w64_mfj_9475-hf-tranciever_manual_d-9.png "Page 10
MFJ-9475 Instruction Manual 75-Meter SSB Travel Radio
10 Receiver Sensitivity: (Use a calibrated RF-Signal Generator)
[ ] Connect a weak 3.900 signal source to ANTENNA
jack.
[ ] Tune in source for maximum S-meter reading using VFO.
[ ] Adjust Signal Generator amplitude for S5-S7 meter reading.
[ ] Touch up L1, L2, T1, T2 for maximum S-meter reading.
Transmitter Bandpass Filter Alignment: (Use a Watt meter and Dummy Load)
[ ] Connect low-power watt meter with dummy-load to the...")
MFJ-9475 Instruction Manual 75-Meter SSB Travel Radio
11 DC Voltage Chart
For advanced trouble-shooters, the following values are typical DC voltages found in the
MFJ-9475 Transceiver:
Vcc = 13.8 Supply Voltage
TP1 = 10.2 (LM-317 Output)
TP2 = 4.3 VDC
Integrated Circuits:
Pin # U1 U2 U3 U4 U5 U6 U7
1 1.4 10.2 1.4 5.0 9.9 1.3 1.4
2 1.4 10.0 1.4 5.0 2.5 1.3 1.4
3 0 0 0 5.0 0 0 0
4 3.9 3.3 4.0 0 2.9 4.9 4.7
5 3.9 4.9 4.0 5.0 4.9 4.9 4.7
6 4.9 3.3 5.0 5.0 0 5.7 5.8
7 4.5 0 4.6 5.0 0 4.9 5.2
8 5.0 10.2 5.1 9.9 4.9 4.9 5.8
BPT and FET Devices: D/E = Drain/Emitter
S/B = Source/Base
G/C = Gate/Collector
* Test in Transmit Mode
** Test with Tune switch depressed
*** Do Not Test gate of Q9 -- may cause parasitic instability.
Q1 Q2 Q3 Q4 Q5 Q6 Q7* Q8** Q9 Q10
D/E 9.8 0 9.0 9.7 0 0 3.5 0 13.0 0.25
S/B 2.3 0.7 3.9 8.9 0.7 0.7 2.8 0 0 1.0
G/C 0 0 0 4.3 13.0 0 0 9.0 *** 13.7
Q11: To avoid meter damage from RF, check Q11s collector voltage in receive mode
only--full supply voltage should be present. Check base bias voltage with PTT pressed
(no audio, mic gain fully off)--it should read approximately 0.6 VDC. A measured
current of 50 uA across the PA bias test points should correspond with 100-mA IDq on
PA transistor Q11 (RFC6 acts as a meter shunt for this measurement).
MFJ-9475 Instruction Manual 75-Meter SSB Travel Radio 12 MFJ-9475 Schematic Diagram
MFJ-9475 Instruction Manual 75-Meter SSB Travel Radio 13 MFJ-9475 Parts List