After the 7th LED flash, does the LED go out completely or does it stay dimly lit?
I would check the following signals on the MPU board with your scope for approximate correct frequencies:
Pin 18 of U10; 120Hz - Zero Crossing Detector signal
Pin 40 of U11; 320Hz - Display Interrupt Generator signal
The symptom you're seeing with attract mode not proceeding can be indicative of issues with the zero crossing signal.