Got an old radio from the ’20s, and want to bring it back to life? Well, the quickest way is probably be to remove all those dusty components and use the cabinet to hide a new stereo. That’s not what radio hacker Greg Charvat had in mind for his, though. Instead, he restored the original radio circuitry, and even hooked it up to his iPod.
Along the way, he ran into all sorts of neat discoveries, and many potential pitfalls. It turns out that electronics have changed quite a bit in the past 80 years, and even the most basic components such as resistors and capacitors can be unrecognizable. Another issue is that the cloth and rubber used for insulation on the wiring will have dried out, making it necessary to handle everything extremely carefully. One nice thing about equipment of this vintage, however, is that it was usually designed to be repaired, so chances are good that a schematic is available.
To give you an idea of the issues one should expect to encounter when attempting this, here is the overview he gives in a presentation about the project:
- Do not power up your radio!
- yes, it does not work
- more harm than good
- Find service manual
- Replace all electrolytic and paper capacitors
- Replace anything that looks damaged (burned or exploded)
- Try radio (wear safety glasses)
- Signal trace through circuit, replacing resistors where needed
- Radio will work
As usual for high-voltage projects, and especially for high-voltage projects involving unknown vintage equipment, don’t attempt this unless you have the proper training, because the electronics inside are most certainly deadly. Don’t give up though, just make sure you learn enough to know what you are doing!