Ericsson LBI-39175A manual Receiver Alignment, Test Equipment Required, Adjustment Procedures

LBI-39175A

wire board runs to separate from the board. Check for shorts and solder bridges before applying power.

CAUTION

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.

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.

NOTE

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.

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.

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