IC7812 measurement (19) leg VDD+9v and (12) feet -9V power supply voltage are normal and stable. Fly line IC7812 (1), (5) foot connected test machine, there is signal output. CE were tested using an oscilloscope (13) feet, DI (14) feet, and CL (15) foot CPU control signal is normal.qXTservice manual download site
Check Ic7812 for Reset PIN (Resee) (18) feet for low-level 0V, so analysts believe that ReseeIN low level, all the analog Ic selection switch is turned off, natural path is disconnected. Check (18) leg reset circuit for peripheral components, C333 has measured significant leakage. With authentic symbol substitution test machine and output returns to normal.qXTservice manual download site