Sennheiser HE 1 TUBE SET Bedienungsanleitung Seite 5

English | Replacing the amplifier tubes
Replacing the amplifier tubes
Illustrations for the instructions can be found
on the fold-out page at the beginning of this
instruction manual.
ATTENTION!
Do not use the HE 1 when the protective cylinders of the amp-
▷
lifier tubes are removed.
When replacing the tubes, wear the supplied gloves so as not
▷
to damage or contaminate the indium tin oxide (ITO) coating
of the protective cylinders and the quartz glass housings of
the tubes.
Always replace all 8 tubes with new ones. Arrange the tubes
▷
in the amplifier exactly as the tubes were arranged in the box
when delivered.
1. Put on the supplied gloves and switch on the amplifier so that
the amplifier tubes fully extend.
2. Set the power switch to
until the status LED goes off (up to 30 seconds).
3. Push and hold the safety pin on the power plug and pull the
power plug from the IEC mains socket.
4. Loosen the quarter turn fastener of the two front protective
cylinders by turning the protective cylinders a quarter turn
counter-clockwise.
5. Remove the old tubes and dispose of them at collection points
for waste electrical and electronic equipment or return them to
your specialist dealer.
2
OFF to switch the HE 1 off and wait