Alchemist travels in time from Middle Ages to the present day, using a magic portal. He meets with a boy, who is living with his parents in a huge old house, that dates back to the Middle Ages. Alchemist is searching for 12 pieces to an ancient compass or device that would point him to the treasure. Treasure is some machine, that makes people fly like birds. The alchemist tells the boy that the machine comes from old times from "before his times".
I remember only two phrases.
#1. Boy asks him where the machine comes from and he says "it was built by a Great Wise man, many generations ago when a Great Sea Empire ruled all of Earth. They warred with another Empire. After the last war, they set off in ships that sailed across Black Sky. And their great city sunk into the ocean."
So, references to Atlantis. After the war, they boarded spaceships and left Earth across Black Sky (Space) and their city disappeared in the sea.
The alchemist was thinking that if find all 12 pieces of the puzzle, a compass would show where the last Atlantian Wiseman/Priest have hidden his machine. So, the boy makes deal with him that the alchemist gets the machine and he gets any gold or treasure that is found with the machine. I don't remember exactly, but I think the boy's parents were having a financial crisis and were on verge of losing their old house due to debts or unpaid bills.
#2. Alchemist finds a hand grenade and thinks it is a piece of his puzzle. He runs about with it thinking about how to activate it. He goes on a golf course, pulls the ring from the grenade, and drops it on the ground. A guy that was playing golf knocks it away just before it explodes. The guy is told, "That was your best shot to date."
I missed many episodes and saw only its end. They find a compass and the treasure, but there was no machine, only gold. So, the boy buys the alchemist a hot air balloon. The last shot was of the alchemist flying in the balloon over the countryside.
If I remember right, Alchemist's name was Grendfield or Klendfield TV Series could be French or British. Not American, but I am not sure.
I watched it maybe in 1991-1995. It was running on Channel 1. Russian state channel. All foreign TV & Movies were fitted with Russian audio. The original audio was always deleted. It was always a synchronous voice-over. Credits also were always deleted. Start and end credits. This was rated as a children's series.