A Type 5491 shaver by Braun with many similarities to the models 7570, 7564, 7664, and 7690.
it has 3 options to operate . it will operate on all 33 but will not come down to off
This might help: Braun Shaver Model 7680 Battery Replacement
Open the case as per tutorial to change the battery. I had similar issue but just not turning on, case was full of hair which prevented the correct operation.