True to the Music
Radial Engineering Ltd.
Space Heater™ User Guide
11
CHANGING THE TUBES
The Space Heater is equipped with four 12AX7 tubes. Although the
Space Heater is intended to provide many years of problem free
service, the tubes are designed to be user replaceable when required.
ONLY use 12AX7 tubes in the Space Heater. Other tubes such as
the 12AT7 and 12AU7 are not suitable, as they operate at different
voltages.
Step 1:
Remove the top cover of the Space Heater. There are
seven hex-style screws on the sides and back of the chassis,
and two Phillips screws on the top panel.
Step 2:
Carefully wiggle each tube out of their socket. Be sure
to apply even pressure to the base of the tube as you pull the
tube out of its socket.
Step 3:
Replace each tube by aligning the pins up with the
socket. Tubes are ‘keyed’ so that they can only be installed
in one position. Once aligned, carefully push the tube in by
applying even pressure across the top of the tube.
Step 4:
Re-install and fasten top cover.
CAUTION: THE SPACE HEATER IS A HIGH VOLTAGE DEVICE.
TURN OFF THE UNIT AND DISCONNECT THE POWER
SUPPLY FOR 10-15 MINUTES BEFORE ATTEMPTING TO
CHANGE THE TUBES. THIS WILL ALLOW THEM TIME TO
COOL AND REDUCE THE CHANCE OF ELECTRIC SHOCK
BY GIVING THE SPACE HEATER’S INTERNAL CAPACITORS
TIME TO DISCHARGE.
STEP 1
STEP 3
STEP 2
STEP 4
