Here’s an owners manual I found on-line for you:
Bunn NHBX-B Coffeemaker User Manual
Your coffee brewer is a HOME unit. We only address COMMERCIAL equipment here.
However, I DO know that there’s no market for repairing home countertop appliances since the cost for a repairman showing up at your door would quickly surpass the cost of your $150 coffee maker. As such, there’s no parts stream on the market to make repairs.
SO, the bad news is…there’s nothing you can do to fix you existing coffee brewer.
The good news is…it has a three year warranty (per the manual I provided you).