Freezer shows AL07; compressor may run continuously or not at all, and temperature control is lost.

Safety first: Unplug the freezer before accessing the control module. Electronic boards contain live and sharp-edged components.

• Power cycle: Disconnect power for 10 minutes, then reconnect. Sometimes transient control errors clear after a full reset.
• Access control board: On De Dietrich freezers, the main PCB is often located behind the top front control panel or in a rear electronics box. Remove the screws and carefully lower the panel.
• Inspect the PCB: Look for burnt components, darkened areas, swollen capacitors, or signs of moisture damage. Check that all connectors are firmly seated.
• Check supply voltage (advanced users): With extreme caution and only if competent, verify that the board is receiving mains power at its input connector. Do not touch exposed live parts.
• Board replacement: If visible damage is present or AL07 persists after checks, the main control board will typically need replacement. Transfer any wiring harnesses one by one to the new OEM De Dietrich board to avoid misconnection.

Because of the risk of electric shock and miswiring, board replacement is best handled by a qualified technician.