Oven does not reach set temperature; preheat takes very long or never completes, but some warmth is present.

Safety first: Disconnect mains power before removing any panels.

• Test top and bottom elements: Access the top grill and bottom bake elements (Toshiba often uses separate elements for upper grill and lower bake). Disconnect each and measure resistance. Replace any element that reads open circuit.
• Check for single-phase loss: For hard‑wired 220–240V Toshiba ovens, verify at the terminal block (with power off first, then carefully with a meter if qualified) that both live lines are present. A missing phase can cause weak heating. This is typically an electrician’s job.
• Inspect element connectors: Loose or oxidized spade terminals can cause partial heating. Clean and tighten connections; replace burnt terminals.
• Control board relay: If elements and wiring are good, the bake or grill relay on the control PCB may not be closing fully. Look for heat damage around the relay. Replace the control board if faulty.

If you are not trained to work on live circuits, limit your work to visual checks and continuity tests with power off, and call a professional for supply and PCB diagnosis.