The problem with transformers is that if a turn shorts out to an adjacent turn, it totally destroys its transformer action but its resistance changes by only .01% or so.
What should its resistance be? Looking at your picture, at a guess the transformer should handle 25 Watts, as they are about 90% efficient, it will dissipate 10% X 25W = 2.5 W. One half of this will be in the iron loss and a half in the copper loss due to the resistance of the windings. So loss in resistance of copper is 1/2 X 2.5 = 1.25W. Again a half should be lost in the primary winding, so the primary winding losses .625 Watts. The current it takes is 25W/230 ~ .1 A. P = I^2 X R, .625 = .1 X.1 X R , R = 62.5 ohms. So give or take your 105 Ohms is correct, its just that the transformer has a different power rating with different losses.
Inspect the transformer carefully to see if there is any damage - knocks to the windings or blackened areas. It might just be possible to carefully pull the turns apart at an area of damage to fix the problem.
Frank