Hello,
it seems, that this case will be very complicated.
Which model is it exactly?
There was a model 23LG and a model 23LW.
LG stands for DC and LW for AC.
Your picture shows 3 tubes. That should mean, that you got the 'LW' version. Even the RMorg has no wiring diagram.
As an exception, the small pictures at RM.org are able to enlarge.
http://www.radiomuseum.org/r/tefag_tefagon_23lg.html
The third tube is possibly a rectifier. But then, the radio shown in the picture should be the model Tefagon 23LW.
The only chance is to search for a similar radio with an almost similar schema.
Maybe the people at wumpus do know something more.
Greetings
Rocco11