Hi again,
thanks so much Uwe and Klaus, for all the info, i really appreciated it. Sorry to say that I had not read it until this morning, after working on my psu...this is what i did;
I checked all the components carefully and discover that R3 and R4 were 10k instead of the 5k of the original schematic. I swapped them for two 8.2 kohms resistors and now i have gotten 119,5 at B+.
I really don´t know if i have acted correctly but the fact is that B+ is nearer from its ideal value now.
Many thanks again and let me know if i should correct something..
Alfredo