Old tube sets to repair itself often.
Fundamental to TSF
If you find an old tube radio, which was not in operation for years, do not plug it into to the power grid. Verify whether it may be connected to 220 V AC. There are also models that may only be operated with direct current.
- Open the unit to a visual inspection. If it is "burned" look, you should consult a professional. Remove definitely carefully with a vacuum cleaner and a brush the dust inside. It is useful to use the vacuum cleaner to blow.
- The knobs must move easily. If this is not the case, it is usually due to gumming of the associated potentiometer or variable capacitors. Loosen the gumming with penetrating oil. If you can remove the parts, even cleaning with ultrasound is useful. Assemble the parts again only when they are dry. Oil no cables or scales.
- Check if the power cord and the plug are still okay. If the insulation crumble, replace the cable and the plug.
- Because a defective tube device emit a jet of flame and can be very hot, a device from which you know nothing, must be taken with utmost caution in operation. Make sure that nothing can burn around. Ask in doubt from the power at the fuse box when you something uncanny appears.
- If the unit is not running, you can get on troubleshooting. Disconnect it absolutely from the mains again. Unload the power supply with a 30 K-ohm resistance for one minute. If you know neither what a resistance yet what is a power supply, leave the troubleshooting and repair to the expert.
Repair of equipment
The following work may be performed only when the device is without power, so the power supply has been unloaded and your tube radio is not connected to the electricity grid.
- The devices are fuses in the control. Replace them always. Clean the contacts and turn them together so that the fuse is firmly clamped. Since old backups can have a high resistance, it must always be replaced before beginning the repair.
- Look for oxidized contacts. Buttons, sliders, and the connectors of the tubes are often so heavily oxidized that it can not conduct electricity. Clean the contacts. The use of contact spray is problematic because it is hardly to apply metered. Spray the spray in a jar and carry it on with a brush.
- Broken pipes are usually identified by a dark coloring. Replace them against identical tubes. Do not experiment with "similar" versions.
If these measures are useless or if you do not have sufficient knowledge to repair tube radios, contact the Society of Friends of the history of radiocommunications eV There you will find not only professionals, but also schematics and help with the procurement of spare parts.