The manual for the Hallicrafters SX-28 IF alignment procedure provides detailed instructions for aligning the intermediate frequency (IF) section, including steps for rough alignment, finding the crystal filter's resonant frequency, and adjusting specific components like the output slug of T2. It also covers troubleshooting techniques such as cleaning contaminated crystals and emphasizes the importance of repeating the alignment process after replacing components in the IF section.

• Brand: Hallicrafters
• Model: PROCEDUREREV.A
• Type: manual
• File size: 24.5 KB

Manual Overview

The Hallicrafters SX-28 IF Alignment Procedure (Rev A) by Bill Feldmann N6PY provides a detailed guide for aligning the intermediate frequency (IF) section of the SX-28 receiver. The manual suggests using a high impedance DC voltmeter across R25, the audio detector load resistor, to measure carrier signal strength, instead of relying on audio and the BFO. The process begins with a rough IF alignment by connecting a stable signal generator to the stator of C1.1 and adjusting the slugs on T1 and T2 for maximum voltmeter reading. The procedure emphasizes finding the crystal filter’s resonant frequency by sweeping the signal generator’s frequency and adjusting the phasing knob. If no peak is found, cleaning the crystal may be necessary. The manual also details the adjustment of the upper output slug of T2 to achieve a good notch for eliminating heterodynes. Finally, the alignment of the first AVC transformer, T6, is covered, with the voltmeter connected across C66 to ensure proper signal detection.

Quick Issues Covered

• Align SX-28 IF using DC voltmeter across R25 for signal strength.
• Identify crystal filter's resonant frequency by peaking voltmeter response.
• Adjust T2 output slug for optimal notch to reduce heterodynes.

Overview

The document provides a detailed procedure for aligning the intermediate frequency (IF) of the SX-28 receiver. It highlights improvements over the original manual’s method, suggesting the use of a high impedance DC voltmeter for better accuracy. The procedure involves several steps, including rough IF alignment, finding the crystal filter’s resonant frequency, adjusting the output slug of T2, crystal filter alignment, and alignment of the first AVC transformer. The document emphasizes the importance of repeating the alignment after using the receiver for a few weeks, especially after replacing components in the IF section.

Specifications

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Controls & Indicators

Refer to the PDF for details.

Installation / Setup

Refer to the PDF for details.

Operation

Refer to the PDF for details.

Troubleshooting & Error Codes

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Safety & Warnings

Refer to the PDF for details.

Download PROCEDUREREV.A Manual (PDF – 24.5 KB)

Hallicrafters SX-28 IF Alignment Procedure Rev.A: Guide for technicians on aligning intermediate frequency stages. PDF size: 24.5 KB.

• Brand: Hallicrafters-sx-28-if-alignment
• Model: PROCEDUREREV.A
• Type: Manual
• File size: 24.5 KB

Overview

Brief overview of the product.

Specifications

• Key spec 1
• Key spec 2

Controls & Indicators

Control panel/button layout.

Installation / Setup

1. Step 1…
2. Step 2…

Operation

Basic usage, modes, cycles.

Troubleshooting & Error Codes

Safety & Warnings

• Important warning…

Downloads

Download PROCEDUREREV.A manual (PDF)