It is a regulator or control of the source unfortunately it could not be read but in the diagram said ncp1251 and I replaced it x the tea1507p nc I know if it is well as I did but it is as I said in the other forums and videos.
Now change the two diodes vd817 and 819 and I got 9 volts in the secondary where I have to have 12 I have 9 to 10 and in the others nothing x that would know if the n801 replace it well xq in the opto I have 9 volts
If I have it connect everything like that with the replacement but less the fb q is connected in the replacement two resistors q and the name is connected to the 1k on the ground and the other one in the opto and joined them and you connect the cable to the replacement would be fb
https://www.youtube.com/watch?v=5cJkk3qH7nw, this video can serve as a guide, login to me repro and everyone starts calling no joda