The RTC's time pulse is too slow or too fast. It should be no less than 57 frames (0.963s), and no more than 64 (1.081s).
Can happen if traces are cut.
- Check 32768Hz crystal
- Check uPD4990 traces, especially pin 11 (TP) and pins 5, 6 and 7.
- Check 74HC32 and traces to uPD4990
- Try to reset Backup RAM content:
- Either remove battery
- Or flip all dip switches to on and then power on the board. Then turn off the board and return all dips to normal settings
- You can use unibios to skip this error