Oven does not respond to any button presses, display shows E0 shortly after power-up.

Safety first: Unplug the oven or switch off the circuit breaker before opening any panels. Capacitors on the control board can retain charge; avoid touching bare circuitry.

• Power reset: Disconnect power for 5 minutes, then restore power and check if E0 clears. Sometimes a transient communication error is cleared by a reset.
• Check control panel ribbon: Remove the top or front trim to access the control panel on your Tristar oven. Locate the flat ribbon cable from the touch panel to the main PCB. Reseat both ends by gently pulling out and reinserting, ensuring the locking tabs are fully engaged.
• Inspect for corrosion or burns: Examine the display/control PCB for darkened areas, burnt smell, or green/white corrosion on connectors. Clean light oxidation with isopropyl alcohol and a soft brush; if tracks are burnt, the board must be replaced.
• Test buttons: With power restored and panels reassembled, test each key. If some keys are dead or E0 returns immediately, replace the touch control panel / keypad assembly specific to your Tristar model.

If the error persists after reseating cables and the keypad tests good, the main control PCB is likely defective and should be replaced by a qualified technician.