First of all I am not an electrician qulified or any other kind.
Most of the users of this forum will be conversant with this, but it may help someone in the future.
Recently a member of the forum posted a post that referred to the installation of a wallbox2mp3 unit in a Rockola 507.
It became clear later that one of the problems that he was having was down to the fact that his transformer had been incorrectly connected, & was not producing
25 V AC.
Originally wallbox’s were connected to a Jukebox which in most cases had a transformer that dropped the voltage down from the mains supply to 25 V AC
When using a wallbox independently it is necessary to supply it with a 25v AC power source, many of the transformers that I have used have six wires for the three windings one pair for the primary winding (mains supply) and two other pairs for the two secondary windings.
If the two secondary windings are wired in parallel you will get half the voltage of what you would get if you were to connect the two secondary windings in series.
It is important to read & understand the infomation for the transformer you are using before making any electrical connections.