3M DX70 Guide D'utilisation page 193

The projector keeps track of the lamp usage. It will show you a warning
message:
When you see this message, change the lamp as soon as possible. Make sure
the projector has cooled down for at least 30 minutes before changing the
lamp.
Warning: Lamp compartment is hot! Allow 30 minutes to cool down before
changing lamp!
1. Turn off the power by pressing the Power/Standby button.
2. Allow the projector to cool down for at least 30 minutes.
3. Disconnect the power cord.
4. Push up and remove the cover.