Mark S New Durham , NH November 09, 2019 Appliance: Bosch Electric Wall Oven HBL5450UC/06 Bosch Wall Oven Hbl5450uc/06: Display only showed 4 small bars in upper left corner, oven would not work. How to replace Display Module. Replacing the display module resolved the problem. It was a fairly easy fix. 6 People found this story helpful Do-It-Yourself Rating: Repair Time Estimate: 30-60 minutes