power supply not work



hi everyon
i have a problem with my bench power supply (ps 305 d)
it from today not work correctly.
the output voltage not can be regulated and is maxim value (32 volts)
on web i found only one schematic, but is different from my board.
on the diagram there is an op-amp lm 324 and another ic, i think an op-amp too, while on my board there are 4 ic. two of these are lm 301 an and others two i not can see the label.
have you some ideas for solve the problem or give me some suggestions for...

power supply not work