Because "SPD" is a generic term across brands, there is no universal key sequence. However, 90% of SPD-based monitors and controllers use one of the following three methods. Try them in order.
If your SPD unit came with an infrared remote:
Note: If that fails, try INFO → FACTORY → 0 → 0 → 0 → 0 on the numeric keypad.
Proceed at your own risk. Modifying system partitions or enabling diagnostic modes can void your warranty or potentially brick your device if not done correctly. Ensure you have a backup of your data.
You have successfully entered diagnostic mode. Now what? Here is the most effective workflow: