PALEOPHONIES FM-DW 2.0

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Summary

FM-DW Converter and AM Saver Installation Guide

Safety and Preliminary Checks

Crucial safety warnings regarding sensitive devices and essential radio checks before installation.

Module Grounding and Tuning Capacitor Integrity

Ensuring proper grounding and the critical condition of the tuning capacitor for optimal performance.

Powering the FM-DW Module

Connecting power to the FM-DW module, covering AC/DC inputs and voltage doubler requirements.

Connecting Antenna, Outputs, and Setup Button

Details on connecting the antenna, audio outputs, and the optional setup push-button.

Mounting and Powering the AM Saver Module

Instructions for physically mounting the AM Saver and connecting its power source.

AM Saver Module Interface Connections

Connecting amplifier inputs, AM detector, tuning capacitor, and switches to the AM Saver.

Advanced Configuration and Troubleshooting

Addressing harmonic interference via vacuum tube modification and AM/FM band switching.

Final Wiring Verification

The final step of checking all wiring connections before powering the radio on.

The Paleophonies FM-DW converter and AM Saver modules are designed to upgrade vintage radios, allowing them to receive FM broadcasts while preserving their original AM functionality and amplifier. The system enables users to tune with the radio's original dial and listen through its existing amplifier, integrating modern FM reception into classic devices.

Function Description

The core of the system is the FM-DW module, which acts as an FM converter. When paired with the AM Saver module, it allows for seamless switching between FM and the radio's original AM bands. The FM-DW module processes FM signals, converting them into a format compatible with the vintage radio's amplifier. The AM Saver module manages the AM circuitry, ensuring that it is properly integrated and protected when the FM-DW module is active. This dual-module approach ensures that the radio's original AM functionality is retained and can be easily accessed.

The system is designed for installation by individuals with sufficient electronics background, particularly those experienced in restoring vintage tube and transistor radios. This is crucial because the modules use electrostatic sensitive devices, and improper handling or installation can lead to damage. The installation process involves careful grounding, power supply integration, and connection to various parts of the radio's existing circuitry, such as the tuning capacitor, antenna, and audio amplifier input.

Important Technical Specifications

Power Supply:
- FM-DW Module: Accepts alternative current (AC) from 4V to 10V or direct current (DC).
- AM Saver Module: Accepts 4V to 6V (AC or DC).
- Current Draw:
  - FM-DW radio section: Under 50mA.
  - On-board 5V regulated power supply (if used): Up to 50mA.
  - AM Saver add-on module: Around 100mA (turned off in FM mode).
- Minimum DC Voltage (with on-board +5V regulated output): 6V (4V otherwise).
Operating Temperature: The FM-DW module operates at a maximum temperature of 50°C. It must be placed far from heat sources like rectifying and output tubes to prevent frequency drift and performance degradation.
Antenna Connections:
- The FM-DW Antenna pad connects differently based on configuration.
- For AC/DC sets, a 1 Megohm resistor should be added between the FM-DW antenna pad and the chassis.
- The AM antenna plug connects to the FM-DW module's antenna pad.
- If AM circuitry attenuates the FM signal, a separate FM antenna is required (a 120 ohms type is recommended, though a 3ft wire is often sufficient).
Audio Output: The FM-DW L OUT and R OUT pads connect to the AM Saver, which then feeds into the radio's LF amplifier input(s). The Amplifier L pad is used for mono receivers, while the Amplifier R pad is for stereophonic amplifiers.
Capacitance: A capacitor (typically 10nF) is recommended before the LF amplifier input(s) for AC/DC radios if not already present.
Diode Requirements: If powering the AM Saver from a 6.3Vac heater circuit, a rectifying diode with a voltage drop of 0.6V to 1.2V and a forward current of at least 200mA must be inserted.

Usage Features

Original Dial Tuning: The system allows users to continue using the radio's original tuning dial for both AM and FM reception, maintaining the vintage aesthetic and user experience.
Original Amplifier Integration: Audio output is routed through the radio's existing amplifier, preserving its characteristic sound.
AM/FM Switching: The AM Saver module facilitates switching between AM and FM modes. This can be done via an external switch connected to the AM/FM Switch pads, potentially utilizing existing band selector terminals or a separate microswitch.
Setup Push-button: The FM-DW module includes a Setup pad for connecting an additional push-button, allowing for configuration and calibration of the module. The AM Saver module has a hole to access this push-button when stacked.
Power Supply Flexibility: The modules can be powered from various sources within the radio, including heater windings (with or without voltage doublers depending on voltage and center tap configuration) or a separate DC power supply for radios with series-connected heaters.

Maintenance Features

Pre-installation Checks: Before installation, it is crucial to ensure the radio is properly restored and its amplifier works correctly. The radio must be unplugged from the mains during the entire installation procedure. The mains switch should be clean and free of excessive arcing, with a suppressor capacitor added if needed.
Heat Management: The FM-DW module must be placed in a cool location, ideally under the chassis, and away from heat-generating components like rectifying and output tubes. This prevents temperature-induced frequency drift and ensures stable performance.
Tuning Capacitor Condition: The tuning capacitor's condition is critical. It must be free of contact faults, excessive dust, and shorts. Its body must be properly grounded, and fixed plates should not be connected to high voltage to prevent damage to the FM-DW module. For DC radios with a chassis connected to the positive terminal, the tuning capacitor's body must be insulated from the chassis.
Oscillator Adjustment: Due to increased capacitance from the FM-DW module, the radio's oscillator should be checked and potentially adjusted before the FM-DW setup.
Harmonic Suppression: If the AM section produces harmonics that interfere with FM reception, a specific modification to the frequency changer tube circuit may be required. This involves disconnecting the cathode from ground and adding an 82-ohm resistor between the cathode and the "Vaccuum Tube" pad on the AM Saver module.
Grounding: Proper grounding of the FM-DW module to the chassis is essential, especially for AC/DC sets, using its three grounded holes and fully grounded bottom side for a solid attachment.
Module Stacking: The AM Saver module mounts directly over the FM-DW module using spacers, ensuring no short-circuits with other pads and that the grounds of both modules are connected.
Wiring Verification: A thorough double-check of all wiring is mandatory before powering on the radio to configure the FM-DW module.