Hi there Manel and welcome to Electronics Point
Sorry about the slow response!
I got a copy of the service manual from elektrotanya but it doesn't seem to have any information on the external charger. Please tell me if I'm missing something here.
A rapid clicking sound from a switching power supply is called "hiccuping" and it's caused by one of the safety circuits activating. The power supply starts up, then at a certain point, the current or voltage exceeds the safety limit, and the safety circuit kicks in, shutting the power supply down. Then it starts up and tries again. This can happen pretty quickly, leading to a clicking or even a low-pitched buzzing sound.
There are several types of faults that can cause this symptom. Blown fuses are not generally one of them. It may be as simple as a shorted diode in the output circuit, or even just an electrolytic, but it may require some diagnosis.
If you want to fix it, we will help, but we need you to understand that switching power supplies are potentially very dangerous. The live side has a voltage of at least 160V DC, often 320V DC, both of which can kill you if you connect yourself across it the wrong way! You need to be very careful making measurements when the power supply is running. Initially your measurements can be made with it unplugged, but the large cylindrical electrolytic(s) (one or two of them, usually) can store enough energy to kill you, and they may need to be discharged.
The best way to discharge them is with a power resistor of about 10 kΩ rated for 5W (see
http://www.digikey.com/product-detail/en/AC05000001002JAC00/PPC5W10.0KCT-ND/596680) which you connect across each capacitor for at least 20 seconds (making sure you don't touch either of the wires - or the resistor, as it will get hot for a short time). But you can just short it out with an insulated screwdriver (as long as you don't mind a loud BANG! and a chunk being taken out of the screwdriver and the pin)!
The capacitors often have a "bleeder resistor" across them, which will discharge them within 5~10 minutes after the power has been removed.
You will also need a multimeter and basic knowledge of how to use it.
Are you confident you can work safely on the power supply and make measurements? If so, open it up and upload some photos of both sides of the board. See
https://www.electronicspoint.com/resources/how-to-take-photos-of-circuit-boards.6/ for guidelines on how to take good useful photos.
Edit: In your original post you say the recorder unit, not the power supply, is the problem, and you know this because you've tried a different power supply. How sure are you that the power supply you tried was working, and had the right voltage and current ratings and the right polarity on the connector? My first suspicion is that you should fix the power supply that's supposed to work with that unit, then see if the unit works.
