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When someone says “restoring an old radio,” many of us imagine just a dusty piece of non-functional furniture. But some radios don’t deserve to remain just retro decorations – they deserve a second chance. And the Liberator – the Telegrafia C420 radio from 1945 – is certainly one of them. 

Since this namesake “predecessor” is interwoven with our company’s history, we decided to breathe new life into it. Specifically, the engineers from our hardware development team have placed the shem into this Golem — and thanks to their efforts, we are not only reviving postwar-era technology, but also restoring a piece of our company’s heritage that proudly recalls our roots. 

The Liberator is no ordinary device. Its development began during World War II, but it wasn’t manufactured until after the war ended. That’s why it was given the symbolic name “Liberator.” It was the last model to bear the Telegrafia brand, as shortly thereafter the company was nationalized and absorbed under the Tesla brand (Pardubice, CZ). 

Our specific piece was made in 1945. It was manufactured for just two years and is truly a piece of history – now 80 years old! 

By today’s standards, it may seem like a technological dinosaur. But don’t be fooled – its operating principle is, in many ways, the same as in modern radios. It uses what’s known as a superheterodyne – a signal processing technology that is still used today. Of course, we’re simplifying things a bit – components have shrunk, modulation methods have evolved, but the core principle remains mostly the same. 

The radio has four frequency bands (long wave, medium wave, and two shortwave bands) and even a phonograph input. Its output is around 2.5 W – enough to fill a living room in the mid-20th century with sound. 

When the radio arrived to us, it was clear it had undergone multiple repairs. It already contained some Tesla-branded parts. The first step in the restoration was removing dust, cobwebs, and checking the electronics. Thankfully, this phase didn’t involve removing any dead rodents – which, believe it or not, is not uncommon in similar restorations. 

Back when the Liberator was manufactured, paper capacitors were used as dielectrics. These were impregnated with a special compound and sealed with asphalt in a hard rubber tube. But time changes everything – over the decades, the asphalt lost its seal, the paper absorbed moisture, and failures followed. So we had to replace them all. One of our priorities, however, was to preserve the authentic look of the components, as well as the radio’s original appearance. 

What else? We repaired the volume potentiometer, cleaned the switch mechanism, and gradually restored all functional blocks. One of the biggest challenges was fixing the intermediate frequency transformers. While a previous technician simply disconnected one of them, our team chose not to cut corners – we returned everything to its original state. 

Step by step, wire by wire… the radio was technically functional again. It played beautifully through the phonograph input, received signal from a radio transmitter, and the magical tuning eye on the scale glowed again. It was time to focus on the exterior and refine the appearance. 

The cabinet was left with its original lacquer – we only cleaned it and repaired minor blemishes. We replaced the dirty speaker cloth and added a vintage-style linen-braided power cord. The result? A radio that not only sounds great but looks impressive – a dignified tribute to a time when technology was crafted with both heart and hands. 

Although long and medium wave broadcasts are no longer active in our region, the radio is fully functional. At night, when conditions are best, it can receive shortwave broadcasts from various parts of the world. And if you connect a phonograph – or another analog source – the Liberator becomes a fully functional music player once again. 

Restoring this historical radio was a blend of technical skill, respect for the past, and a touch of patience. But the result – that’s pure nostalgic joy. 

The article was written by

Róbert Jakab

Robert is like a moving photograph – because he is like a video. He can capture 60 frames per second. Whenever something happens, he records it. Currently, he’s working on smaller videos and hoping to make a feature film one day and then its sequel. Telegrafia 2: Monkey Power