Ericsson LBI-39175A - Manual (Page 12)

LBI-39175A
12
wire board runs to separate from the board. Check
for shorts and solder bridges before applying power.
Failure to solder the transistor leads as directed
may result in the generation of RF loops that
could damage the transistor or may cause low
power output.
CAUTION
RECEIVER ALIGNMENT
Alignment of the Front End and Local Injection
circuits are not required because band-pass filters are
employed in the ORION wide-band synthesized radio
receiver.
TEST EQUIPMENT REQUIRED
•
Distortion Analyzer
∗
•
AC Voltmeter
∗
•
RF Signal Generator
∗
•
Frequency Counter (136-174 MHz)
∗
•
4-Ohm, 25 Watt Resistor
•
Audio Isolation Transformer (1:1)
19A116736P1 or equivalent **
∗
These four items can be replaced with a Service
Monitor HP8920A or its equivalent.
** See Figure 4. This is not needed if instrument
input is unbalanced with respect to ground.
Before aligning the receiver or making any
adjustments to the radio, be sure that the outputs
of the 9 Volt Regulators IC230, IC503, and
IC481 are 9.0
±
0.2 VDC.
NOTE
ADJUSTMENT PROCEDURES
Receiver Frequency Adjustment
No receiver frequency adjustment is required.
2nd Receiver Oscillator
Using a frequency counter to monitor Terminal TP5,
set L521 for a frequency of 44.645 MHz
±
200 Hz.
IF/FM Detector Alignment
Apply a 1000 microvolt, on-frequency test signal
modulated by 1000 Hz with standard deviation to antenna
jack J1.
Connect a 4-ohm, 25-watt resistor in place of the
speaker. Connect the isolation transformer input across
the resistor. Connect the isolation transformer output to
the Distortion Analyzer (see Figure 4).
Adjust the VOLUME control for 15 watts output
(7.75 VRMS) using the Distortion Analyzer as a
voltmeter.
Set the output signal level of the RF signal generator
so as to obtain 12 dB SINAD at the audio output.
Adjust coils L502, L504, L505, and L507 to obtain
minimum 12 dB SINAD.
Set the output signal level of the RF generator to
1000 microvolts.
Adjust L523 for maximum audio output.
Adjust RV501 for XTONEDEC output at ORCC to
500 mVRMS.