MK191 : How to start the game?

Hi !
My son just completed the mini-kit of this electronic tennis game.
It seems to be working : when plugged to the TV, we can see the rackets and the ball, move them with the knobs, change mode with the push button on the main board… but the game never starts.

Is there something we missed ?
We thought it could start with a press on the push button on the left pad… but it doesn’t.
Is it a wrong soldering ?

Thank you for any help.

Instructions are on top of the board.
You will need to press and hold the left up player and then press restart.

Hello, my son has the same problem, and i don’t see any instruction on the board? It only says short =off long =game mode. The restart button only changes the game mode, also in combination with the smash button. Any other ideas?

If you can move the bat on the left, then the left button should start the game.
To test the button, you can also bridge the 2 wires on the board, this has the same function like the button.
PS. make sure you have good batteries