Portable 10 transistor multi-band radio: long waves, medium waves and six short waves bands.

It’s a typical superheterodyne set and it’s a successful project, these radios work very well and can receive several stations on medium, long and short waves.
In the front panel you can see: a small knob for the power switch / volume control and a largest knob for the tuning.

On the tuning dial, in the left, there is a pushbutton to illuminate it.

On the right side of the set there is a rotating switch band and a smallest knob for the tone control.

On the rear side you can see: a socket for the external antenna, a plug for an external power supply, a jack for headphones and a DIN socket for a recorder.

Some of this radios have a coaxial socket for the external power source, in this case, the central pin has to be connected to the positive pole of 9 V c.c.

The telescopic antenna, when extract, is 79 cm length.

The main problem this radios have, are the Silver contacts of the rotating band switch.

As the time goes by, they oxidize and this causes the malfunction of the set.

But that isn’t a problem, you only have to clean the contacts of the rotating switch with a cloth to clean the Silver.

After that, you have to lubricate them with a grease for electrical contacts and the radio will work wonderfully for many years.

Avoid using an abrasive cleaner, because it can damage the Silver plating.