Brushroll Performance Indicator (BPI)...
The BPI indicator light is not a light bulb, but a green colored LED which should never burn out! So if it doesn't light, there are several possibilities:
1. The Brushroll is not spinning because the belt is not properly engaged.
2. The Brushroll is not spinning because the belt is broken or missing.
3.The Brushroll is installed backward.
4. The Brushroll is the wrong one for the 9700. It may not have a magnet imbedded into the wood at one end. The magnet is what energizes the BPI light. AS the brushroll spins the magnet passes very closely to a tightly wound coil of wire on each revolution. This induces a small current in the coil which lights the LED.
5. If the brushroll bearings are imbedded with hair and dirt/crud, the brushroll may not reach full speed of approx. 3900 RPM. If not, the BPI will blink rapidly. I have seen brushrolls so clogged up with hair and gunk, that they are completely seized and won't spin at all.
Here is a very good video of how to replace the Belt and Brushroll on your Royal: