Sennheiser HE 1 User Manual page 30

Using the HE 1 | Switching the tube headphone amplifier on
28
Deactivating the blockage protection
If, during initialization, the operating elements and the amplifier tubes cannot
extend automatically because they are blocked or if the glass cover cannot
open because it is blocked, the blockage protection will be activated. The
status LED flashes red. In this case, the HE 1 cannot be used.
To deactivate the blockage protection of the HE 1:
Set the power switch to
▷
LED goes off (up to 30 seconds).
Make sure that the operating elements, the amplifier tubes and the glass
▷
cover are not blocked.
Set the power switch to
▷
It might be that the operating elements retract to the "off" position.
Press the on/off button.
▷
The HE 1 switches on normally (see previous page).
OFF to switch the HE 1 off and wait until the status
ON to switch the HE 1 on again.