ZX hardware - Modifying an EI Nikola Tesla Radio

Radio Amplifier

In the previous issue, we began publishing radio amplifier modifications, and we continue with them in this issue.

Most of you probably have this type of radio: an EI Nikola Tesla. Its modification is just as simple, but it requires a little more time and care. You will need:

• a soldering iron rated up to 25 W;
• two thin wires;
• a banana plug;
• solder wire (some people call it tin);
• a radio;
• and a little luck.

First, open the radio and turn the printed circuit board towards you. You will notice a large white wheel used for tuning stations. The IC pins are located directly above it. The IC is a TDA1083 or a similar TDA chip. There is a small hole at the last pin when viewed from the white wheel, or at the first pin when viewed from above on the left-hand side. On some radios, this hole may be soldered over, so you may not be able to find it; use the picture above as a guide.

Solder one longer wire at that point. Be careful not to let solder drip onto the adjacent track, or accidentally bridge the hole and the uppermost track with solder. If you do, you will not be able to turn up the volume (the author of this section knows this from experience).

Once you have done that, follow the red wire from the batteries—or, if there is no red wire, follow the positive wire. Wherever it meets the board, that is, wherever it is soldered, solder your second wire as well. Connect both of your wires to the banana plug, and that is all.

One more thing: the radio has two switches on the back. If you flip either of them, you will not hear the music, but the sound quality will be better.

Ž.S.