Oster Control board initialization or display test mode

Display shows 8888 or all segments lit and the microwave is unresponsive.

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

Possible Causes

Control board stuck in self-test, Power surge affecting microcontroller, Faulty display driver on PCB

Safety first: Unplug the microwave before extended troubleshooting.

Power cycle: Unplug for 10–15 minutes, then plug back in. Many boards will reset from a stuck test mode.
Button test: Try pressing CLEAR/STOP or CANCEL several times. If the display remains stuck, the control board may be locked.
If condition persists: The main control board or display module is likely defective and will need replacement with an Oster-compatible board.

Hard 4/5

Main Control Board (PCB)

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