Alignment Procedures - Uniden SMH 4000 Service Manual

Transmitter Alignment
Adjust
Step Channel
1
•13.6 voe
Power Slipply
2
3
4
Note: Always use a non-metallic adjustment tool to make adjustments.
2 VR301 and CT301
5
6 3 CT301
VR301
7 2
8 1 VR301 Power Control
9 2 L402 Reference
Oci llator
1 0 3 VR401 CTCSS
Deviation
1 1
AF SiO'lal
Generator
1 2 2 VR202
Voice Deviation
1 3 4 VR601
CTCSS Deviation
1 4 VR201 Total Deviation
Page 24
Alignment P rocedures
a. Connect frequency counter, deviation meter, R F power
meter, and RF dummy load to antenna jack.
b. Connect
Power COf'Vl8ctor Antenna
SMU 300
Turn radio O N .
Turn squelch control (SQ) fully clockwise to squelch
receiver
Set VR201 , V R202, and VR601 to middle position.
Remove R F power ampl ifier PCB shield. Key transmitter
and Power Control adjust VR301 for 42 watt reading on
power meter.
Key transmitter and adjust CT301 for maximum reading on
power meter.
Key transmitter and adjust VR301 for 42 watt reading on
power Power Control meter.
Key transmitter and verify that read ing on power meter
does not
Typical power meter readings for channels 1 , 2, a nd 3
should be:
Channel 1
C han nel 2
C hannel 3
Key transmitter and adjust L402 for 1 50 .505 M Hz
(±200 Hz) reading on frequency counter.
Key transmitter and adjust VR401 for 1 73 .500 MHz
(±200 Hz) reading on frequency counter.
a . Connect frequency counter, deviation meter, and
R F d ummy load to antenna jack.
b. Connect AF signal ge nerator to either pin of J201
with 2.7 k n resistor.
Set AF signal generator to 1 kHz at 1 Vrms. Key
transmitter and adjust VR202 for 2 kHz reading on
deviation meter.
Key transmitter a nd adjust V R601 for 750 Hz (± 50 Hz)
reading on deviation meter.
Set AF signal generator to 1 kHz tone with 30 mVrms level.
I np ut this sig na l to audio input of microphone jack. Key
transmitter and adjust VR201 for 4.7 k Hz readi n g on
deviation meter.
S M H 4000
Remarks
+
1 3.6 VDC power supply to radio's power cord.
500
RF
D.mv ny
RF Power
Load
Meter
exceed 50 watts. Adjust V R301 if necessary.
= 48 watts
= 42 watts
= 38 watts
5(0 RF
Dummy
Antenna
Load
Frequency
Co1.M1ter
Deviation
Meter
Frequeney
Counter
Ooviation
Meter
Decem ber 1 992