Hi! I managed to sort some things out.

The square ports in the back of the console should be obvious for you but as I can't read Russian, I had the aid of Wikipedia to read what's written on them. They read "Joystick" and are Sinclair Joystick compatible.

The round DIN plug in the back is the tape interface, there it reads "MAGN" (as in Magnetic Tape). Pin 5 is "ear", pin 4 is "mic". I don't know what the other pins are, I don't think they are unused as there are wires coming from them to the board, but I wasn't able to sort them out yet.

The round DIN plug at the side looks like a kempston interface. Not sure. All pins are 5V.

I couldn't dig anything else further because its TV system is SECAM, my TV can only show either NTSC or PAL-M. The image output is almost useless in this TV. I had the hopes to find a composite video out, but to no avail. No hopes for a RGB signal, I think.

Let me know if you have any information, please.

Thanks again.