The Hammarlund service bulletin provides detailed instructions for setting up and operating the HX-500, including modifications for push-to-talk circuits, phone patch connections, and adjustments for audio distortion. It also offers troubleshooting advice for common issues such as blown fuses, intermittent crystal activity, and driving linear amplifiers, ensuring optimal performance and reliability of the unit.

• Brand: Hammarlund
• Model: BULLETIN
• Type: service manual
• File size: 750.5 KB

Manual Overview

The Hammarlund HX-500 service bulletin provides detailed guidance for troubleshooting, diagnostics, and modifications to enhance the unit’s performance. For push-to-talk functionality, technicians are advised to replace the microphone connector with an Amphenol type 80PC2F chassis receptacle and make specific wiring adjustments to energize the VOX and antenna relays. When using phone patches, connecting the output to the microphone input may be necessary for sufficient modulation. The bulletin warns against rapid power cycling to prevent fuse blowing and potential damage to components like the 6146 tubes. If fuses continue to blow, technicians should inspect the 12AX4 and 6AL5 rectifiers. The ALC control should be adjusted for optimal performance, especially when driving linear amplifiers, and a matching unit is recommended to maintain low SWR. For audio distortion issues, modifications to the first audio stage are suggested, including resistor and capacitor changes. Intermittent crystal activity can be addressed by modifying the 6C4 circuit to include feedback with a resistor and capacitor.

Quick Issues Covered

• Diagnose fuse blowing issues; check 12AX4 and 6AL5 rectifiers.
• Adjust ALC control for optimal performance with varying antenna impedance.
• Use schematics for tracing push-to-talk circuit modifications.

Overview

Refer to the PDF for details.

Specifications

Refer to the PDF for details.

Controls & Indicators

Refer to the PDF for details.

Installation / Setup

Refer to the PDF for details.

Operation

The operation of the HX-500 involves several key steps and considerations:

1. Push-to-Talk: To use a microphone with a push-to-talk feature, replace the current connector with an Amphenol type 80PC2F chassis receptacle. Connect the terminals as specified to enable the push-to-talk function, ensuring the operation switch is in the VOX position and the VOX sensitivity control is set to avoid undesired tripping. This setup can also be used for external control or a foot switch.

2. Phone Patch: The phone patch jack is designed for units with 0 db output at 500/600 ohm impedance. If modulation is insufficient, connect the output to the microphone input for additional gain.

3. General Operation: Avoid rapidly switching the transmitter on and off to prevent blowing fuses and damaging components. If a fuse blows, replace it with one of the same rating and check for issues with specific components. Allow tubes to cool for about a minute before turning the transmitter back on.

4. ALC Action: The ALC control adjusts the action, with more action in a counter-clockwise rotation. The function switch can be placed in the DSB position for adjustment. ALC action may be reduced or eliminated if driving a linear amplifier with varying impedance.

5. Driving Linear Amplifiers: Use a matching unit between the HX-500 and the linear amplifier to maintain a low and uniform SWR. Adjust the transmission line length if necessary.

6. Audio Distortion: To handle high-level output from microphones, modify the first audio stage as specified to reduce distortion.

7. Intermittent or Non-Crystal Activity: Modify the 6C4 circuit to provide feedback if the heterodyne oscillator stage fails to oscillate.

Troubleshooting & Error Codes

Refer to the PDF for details.

Safety & Warnings

Do not snap the transmitter on and off rapidly, as this may result in blowing fuses, possibly causing arcing in the high voltage rectifiers and damage to the 6146 tubes. If the fuse blows, replace it with one of the same slo-blo current ratings. If the fuse continues to blow, check for arc-over in the 12AX4’s and also check the 6AL5 bias rectifier, replacing if necessary. If the transmitter is turned off, allow approximately one minute for the tubes to cool before turning it on again.

Download BULLETIN Service manual (PDF – 750.5 KB)

Service manual for Hammarlund-hx-500-mod-BULLETIN; assists technicians in troubleshooting and calibrating the device. File size: 750.5 KB.

• Brand: Hammarlund-hx-500-mod-service
• Model: BULLETIN
• Type: Service manual
• File size: 750.5 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 BULLETIN service manual (PDF)

The Hallicrafters BULLETIN 1951-30 manual provides instructions for enhancing receiver models SX-28 and SX-288 by implementing new noise limiting circuitry and interconnecting with a panoramic unit or oscilloscope. It also details the installation of a crystal marker oscillator and emphasizes the importance of checking IF stage alignment after circuit modifications, recommending professional service if necessary.

• Brand: Hallicrafters
• Model: BULLETIN
• Type: service manual
• File size: 1.2 MB

Manual Overview

The Hallicrafters BULLETIN 1951-30 provides detailed instructions for enhancing the performance of receiver models SX-28 and SX-288 through circuit modifications. The bulletin outlines a new noise limiter system that replaces the existing shunt type limiter circuit with a series limiter circuit using a 6AL5 diode. This modification requires mounting the diode close to the second detector tube V7 (6B8) and making specific adjustments to resistor and capacitor values to minimize capacitance. Additionally, the document describes the integration of a crystal marker oscillator and provisions for connecting to a panoramic unit or oscilloscope. The reconfiguration allows the use of the 6H6 tube socket for these new applications. After implementing these changes, it is crucial to realign the IF stages due to potential detuning. The bulletin advises using authorized Hallicrafters service centers for these conversions if proper equipment and expertise are unavailable, ensuring the receiver operates at peak efficiency.

Quick Issues Covered

• Diagnose noise limiter issues with SX-28 and SX-28A models.
• Adjust IF stages after circuit modifications for optimal performance.
• Trace circuits using provided schematics for noise limiter upgrades.

Overview

The document discusses enhancements for receiver models SX-28 and SX-28A, focusing on noise limiting circuitry and interconnection with a panoramic unit. It describes modifications to improve noise limiting, including changing to a series limiter circuit using a 6AL5 diode. It also covers the integration of a crystal marker oscillator and adjustments for using an oscilloscope or panoramic unit. The document provides guidance on circuit changes and alignment checks, recommending professional service if needed.

Specifications

• – Receiver Models: SX-28, SX-288
• – Provision for 100, 500 RG or 1 MC Crystal
• – Marker Oscillator
• – Noise Limiter System
• – 6AL5 Diode in Series Arrangement
• – 6B8 Second Detector Tube
• – 6H6 Diode
• – Amplified IF Signal from 6SG7 (V9)
• – 6SL7 Tube
• – 455 ke Output
• – Transformer T-5 in Plate Circuit of ABT Tube

Controls & Indicators

Refer to the PDF for details.

Installation / Setup

The source provides information on enhancing the use of certain receiver models by incorporating new developments in noise limiting circuitry and interconnecting with a panoramic unit. It describes changes to the noise limiter circuit, including the addition of a 6AL5 diode and the removal of a resistor diode. The 6AL5 should be mounted close to the second detector tube V7 (6B8). Circuit differences, such as values and interconnections, should be noted, and low-capacity leads are recommended for connections. The 6H6 diode is retained for use in the new noise limiter circuit, and its socket can be used for other applications. After circuit changes, alignment of the IF stages is necessary due to detuning. If the necessary equipment is not available, an authorized service center can perform the conversions and overhaul the receiver.

Operation

Refer to the PDF for details.

Troubleshooting & Error Codes

Refer to the PDF for details.

Safety & Warnings

Refer to the PDF for details.

Download BULLETIN Service manual (PDF – 1.2 MB)

Hallicrafters SX-28 BULLETIN service manual: troubleshoot and calibrate SX-28 receivers. File size: 1.2 MB.

• Brand: Hallicrafters-sx-28-service
• Model: BULLETIN
• Type: Service manual
• File size: 1.2 MB

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 BULLETIN service manual (PDF)

The service manual for Hallicrafters covers the setup, operation, and troubleshooting of the Model SR-400 Cyclone II transceiver, which is designed for SSB and CW signals on various Amateur Bands, and the Model CR-44A portable receiver, which includes a direction finder for multiple frequency bands. It provides details on power supply options for the SR-400 and includes information on obtaining additional service literature.

• Brand: Hallicrafters
• Model: BULLETIN
• Type: service manual
• File size: 110.4 KB

Manual Overview

The service manual for the Hallicrafters models SR-400 “Cyclone II” and CR-44A provides detailed guidance on troubleshooting, diagnostics, calibration, and board-level adjustments. For the SR-400, a precision-built transceiver designed for SSB and CW signals across various amateur bands, the manual outlines a troubleshooting flow that assists technicians in identifying and resolving issues related to signal transmission and reception. Error codes and diagnostics are detailed to facilitate quick identification of common faults. Calibration and adjustments are necessary to maintain optimal performance, especially when switching between the fixed station and mobile operation modes using the PS-500-A-AC or P-500-DC power supplies.

For the CR-44A, a five-band direction finder portable receiver, the manual includes instructions for troubleshooting reception issues across its wide frequency coverage, including AM, FM, longwave navigation, and public safety bands. The manual provides guidance on using the direct readout azimuth indicator and null meter for accurate direction finding. Board-level guidance is available for both models, ensuring technicians can perform necessary repairs and adjustments to maintain device functionality. Additional service data can be acquired from Hallicrafters for further reference.

Quick Issues Covered

• SR-400 Cyclone II: Diagnostics for SSB and CW signal issues.
• CR-44A: Calibration of azimuth indicator and null meter.
• SR-400: Power-up failures with PS-500-A-AC power supply.

Overview

The document provides service data for new Hallicrafters communications products, specifically the Model SR-400 “Cyclone II” and Model CR-44A. The Model SR-400 Cyclone I is a high-performance transceiver designed for SSB and CW signals on various Amateur Bands and operates with specific power supplies for fixed or mobile use. The Model CR-44A is a five-band direction finder portable receiver covering various frequencies with features like a direct readout azimuth indicator and null meter.

Specifications

• MODEL SR-400 CYCLONE II
• – Precision built
• – Compact
• – High performance transceiver
• – Designed for transmission and reception of single sideband (SSB) and continuous wave (CW) signals
• – Operates on 80, 40, 20, 15, and 10 meter Amateur Bands
• – Operates with Model PS-500-A-AC power supply for fixed station
• – Operates with P-500-DC power supply for mobile operation
• MODEL CR-44A
• – Five-band direction finder portable receiver
• – Covers standard AM and FM broadcast
• – Covers longwave navigation (185-400 kHz)
• – Covers marine and shortwave (2-5.2 MHz)
• – Covers public safety, weather, police, and fire (152-174 MHz) frequencies
• – Direct readout azimuth indicator
• – Null meter

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

Refer to the PDF for details.

Safety & Warnings

Refer to the PDF for details.

Download BULLETIN Service manual (PDF – 110.4 KB)

Hallicrafters SR-400 Cyclone II service manual PDF aids technicians in troubleshooting and calibrating the BULLETIN model. File size: 110.4 KB.

• Brand: Hallicrafters-sr-400-cyclone-ii-service
• Model: BULLETIN
• Type: Service manual
• File size: 110.4 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 BULLETIN service manual (PDF)

The service manual for the Hallicrafters Model S-40A covers the setup and operation of the radio, including details on tube configuration, speaker impedance, tuning range, and power supply requirements. It also provides troubleshooting guidance such as replacing dial lamps, restringing the dial cord, and performing alignment procedures to ensure optimal performance.

• Brand: Hallicrafters
• Model: BULLETIN
• Type: service manual
• File size: 1.3 MB

Manual Overview

The Hallicrafters S-40A service manual provides detailed instructions for troubleshooting, calibration, and maintenance of the receiver. For troubleshooting, the manual emphasizes checking tube terminal voltages using a 20,000 ohm/volt meter with specific control settings. Error diagnostics are facilitated by understanding the function of each component, such as the band selector and tuning capacitors. Calibration involves precise alignment procedures, requiring the use of a standard RMA dummy antenna and signal generator, with adjustments made through the cabinet’s top and bottom access points. The alignment chart specifies signal frequencies and corresponding adjustments to achieve maximum audio output. Board-level guidance includes replacing components like dial lamps and restringing dial cords, with diagrams illustrating the correct procedures. The manual also lists service parts, including transformers, resistors, and capacitors, with part numbers for easy identification and replacement.

Quick Issues Covered

• Diagnose power-up failures with voltage chart reference.
• Perform alignment using detailed alignment procedure steps.
• Trace circuits with comprehensive schematic diagrams provided.

Overview

The product is the Hallicrafters Model S-40A, which is a radio receiver. The manual covers various technical specifications and procedures, including tube and speaker details, tuning range and controls, power supply, power consumption, alignment procedures, dial cord restringing, and service parts list.

Specifications

• Tubes: Eight plus rectifier
• Speaker: S-anch PM
• Speaker V.C. Impedance: 3.2 ohms
• Headset Output: Low Impedance
• Antenna: Provision for external antenna
• Tuning: Manual
• Tuning Range: Band Selector Frequency
• Intermediate Frequency: 455 kc
• Power Supply: Standard Model 105-125 V. 60 cycles AC
• Power Supply: Universal Model 105-250 V. 25/60 cycles AC
• Power Consumption: 75 Watts

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

Refer to the PDF for details.

Safety & Warnings

Refer to the PDF for details.

Download BULLETIN Service manual (PDF – 1.3 MB)

Hallicrafters S-40A Service Bulletin: 1.3 MB PDF for troubleshooting and calibrating the S-40A model.

• Brand: Hallicrafters-s-40a-service
• Model: BULLETIN
• Type: Service manual
• File size: 1.3 MB

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 BULLETIN service manual (PDF)

The manual for the Hallicrafters Model HT-46 Transmitter provides modification instructions to address a frequency shift issue on certain bands and corrects the calibrate switching function for CW operation. It includes detailed steps for setup, operation, and troubleshooting, along with a schematic diagram and parts list for the modifications.

• Brand: Hallicrafters
• Model: BULLETIN
• Type: manual
• File size: 980.7 KB

Manual Overview

The Hallicrafters HT-46 Transmitter manual provides detailed modification instructions to address a frequency shift issue on the 40M, 15M, and 10M bands and correct the calibrate switching function for CW operation. The procedure involves several steps, including removing the cabinet and bottom covers, modifying connections at the VFO switch (S-5), and making adjustments to the CAL switch (8-3) and OPERATION switch (8-1). Key steps include clipping and relocating various leads, adding a No. 22 tinned wire jumper, and connecting a 3300-ohm resistor between specified points. The manual emphasizes the importance of using appropriate tools such as screwdrivers, wire cutters, and a soldering iron. A schematic diagram and parts list reflecting these changes are included, and users are advised to replace outdated diagrams with the updated versions provided. This ensures proper calibration and operation of the transmitter following the modifications.

Quick Issues Covered

• Corrects frequency shift on 40M, 15M, and 10M bands.
• Fixes calibrate switching for CW operation.
• Includes updated schematic for circuit tracing.

Overview

Refer to the PDF for details.

Specifications

Refer to the PDF for details.

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

Refer to the PDF for details.

Safety & Warnings

Refer to the PDF for details.

Download BULLETIN Manual (PDF – 980.7 KB)

Hallicrafters HT-46 Bulletin manual assists technicians in troubleshooting and calibrating the HT-46 model. File size: 980.7 KB.

• Brand: Hallicrafters-ht-46-engineering
• Model: BULLETIN
• Type: Manual
• File size: 980.7 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 BULLETIN manual (PDF)

The manual for the Hallicrafters HT-40 provides detailed instructions on setting up and operating the transmitter, including modifications to improve harmonic suppression and VFO operation. It also includes troubleshooting tips such as replacing specific components to enhance performance and installing filters to prevent unwanted radiation.

• Brand: Hallicrafters
• Model: BULLETIN
• Type: manual
• File size: 423.1 KB

Manual Overview

The Hallicrafters HT-40 Engineering Bulletin provides detailed instructions for improving the performance and harmonic suppression of the HT-40 transmitter. For enhanced harmonic suppression, modifications to the Tank Coil L10 are recommended, including removing turns from the coil and adjusting tap positions. Caution is advised during the tuning process to avoid tuning to the second harmonic. For earlier models, replacing the choke coil L12 with a resistor is suggested to improve efficiency. Additionally, reducing turns on the parasitic choke L11 can enhance 6-meter band efficiency. To prevent subharmonic radiation during 50-MC operation, a K-band stop filter is recommended. The bulletin also outlines changes to the VFO circuit to improve operation, involving rerouting wires and adding capacitors. Technicians should ensure all wiring and solder connections are checked after modifications. These adjustments aim to optimize the HT-40’s performance across various bands while maintaining operational integrity.

Quick Issues Covered

• Tank Coil L10 modification for better harmonic suppression.
• Crystal-VFO circuit changes to improve VFO operation.
• Schematic updates for circuit tracing with Crystal-VFO changes.

Overview

Refer to the PDF for details.

Specifications

Refer to the PDF for details.

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

Refer to the PDF for details.

Safety & Warnings

Caution must be exercised in the tune-up procedure in that 80, 40, and 20 meters will be reached at a point beyond half capacity of the plate tuning and any response near minimum capacity will be tuning the PA to the second harmonic and should be avoided.

Download BULLETIN Manual (PDF – 423.1 KB)

Hallicrafters HT-40 Engineering Bulletin PDF: Aids technicians in troubleshooting and calibrating HT-40 models. File size: 423.1 KB.

• Brand: Hallicrafters-ht-40-engineering
• Model: BULLETIN
• Type: Manual
• File size: 423.1 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 BULLETIN manual (PDF)

The manual for the Hallicrafters HT-37 provides instructions for setting up and operating automatic break-in keying by modifying the potentiometer and adjusting the CW DELAY control for desired transmission delay. It also includes troubleshooting steps for restoring normal CW operation and advises on the availability of necessary parts from the service department.

• Brand: Hallicrafters
• Model: BULLETIN
• Type: manual
• File size: 72.9 KB

Manual Overview

The Hallicrafters BULLETIN manual outlines modifications for implementing break-in keying on the HT-37 model. The procedure involves replacing a single potentiometer (R49) with a dual potentiometer (R49A and R49B) and adding a 4.7 megohm resistor. The VOX control adjustment remains unaffected by this change. To enable automatic break-in keying, set the OPERATION control to “MOX” and adjust the CW DELAY control (R49B) counterclockwise until the VOX relay deactivates. This setup ensures the VOX relay activates with the first key press, initiating transmission. The CW DELAY control determines the delay between transmission end and receiver reactivation; for shorter delays, adjust further counterclockwise. For normal CW operation, the CW DELAY should be at its maximum clockwise position. The adjustment of the CW DELAY control is not required when switching to other modes like DSB or SSB. The dual potentiometer is available from the service department.

Quick Issues Covered

• Adjust CW DELAY for break-in keying on HT-37.
• Install dual potentiometer for VOX control modification.
• Add 4.7 megohm resistor for key line adjustment.

Overview

Refer to the PDF for details.

Specifications

“”

Controls & Indicators

Refer to the PDF for details.

Installation / Setup

Refer to the PDF for details.

Operation

Automatic break-in keying is accomplished by placing the OPERATION control in the “MOX” position and adjusting the CW DELAY control (R49B, sleeve shaft) counterclockwise until the VOX relay de-energizes. When the key is closed, the VOX relay energizes, and transmission begins with the first dot. For shorter delays, turn the CW DELAY control further counterclockwise. To restore normal CW operation on “MOX,” return the CW DELAY control to its maximum clockwise position. The CW DELAY control adjustment does not need to be changed when switching to other manually operated modes such as DSB or SSB. For normal manual CW operation, the CW DELAY control must be in its maximum clockwise position.

Troubleshooting & Error Codes

Refer to the PDF for details.

Safety & Warnings

Refer to the PDF for details.

Download BULLETIN Manual (PDF – 72.9 KB)

Hallicrafters HT-37 BULLETIN manual aids technicians in troubleshooting and calibrating the HT-37 transmitter. File size: 72.9 KB.

• Brand: Hallicrafters-ht-37-information
• Model: BULLETIN
• Type: Manual
• File size: 72.9 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 BULLETIN manual (PDF)