mpg hb04 fault

hi, I have the mpg hb04 wireless configured and working at least until yesterday... when it started not responding by turning counterclockwise, neither as axis movement nor as override. first I replaced the batteries has improved but always with tears on the usual side. then I opened the case and checked with an oscilloscope the phases a and b and they seem to be fine, then the two signals enter the trigger 74hc14d and come out squared and always ok. then they go into an anonymous 20 pin integrated circuit ... if someone has some information it would be useful since there is nothing on the net. regards Mauro

If it can be useful to someone I have solved it. signals a and b were present but the phase was wrong, I recovered a phototransistor from an old mouse (wheel) and by cutting a piece of plastic I was able to change it.
the problem was then to move the photodiode to get the two right signals.