Changing Tubes - VTL S-400 II series Owner's Manual

Changing Tubes

If the amplifier displays a tube fault (either Tube Green or Tube Red fault,) you should replace the faulty tube
according to the tube number displayed on the Display Window. Also if the results of the TUBE BIAS test
indicates that a tube is not operating within the recommended range, you should also replace those tubes as well .
Read the following procedures before changing tubes in your amplifier. If you do not feel comfortable doing the
procedure yourself, please contact your authorized VTL dealer or the VTL factory service department and
request the service to be performed by a trained technician.
Warning: Lethal voltages and high, internal temperatures. Under no
circumstances should the amplifier be operated without the cover.
Open the protective cover:
of the amplifier cover, which can expose potentially lethal voltages. Be sure to only touch the tubes
themselves, and do not allow any part of your body or hanging jewelry to come into contact with any part of
the circuit inside the unit.
Removing the top cover to gain access to the tubes.
When the amplifier was first shipped from the factory, the top cover was installed with locking screws. The screw
should be removed by the customer for easy access to the tubes inside the amplifiers.
User input: The top cover of the amplifier is fitted with thee long screws in three strategic locations along the top
cover. To remove the top cover, the user need to remove these three screws. (See Fig. 7). After the
three long screws are removed, gently lift up the top cover. Enclosed in the customer care package
are three shorter replacements screws. Install these three shorter screws to replace the three removed
screws. This shorter screw will allow the user to remove or replace the top cover without using any
tool in the future.
Locations of the Top Cover Screws on the back and side of the Amplifier
Status: Save the three long screws. The user will need to replace the three newly install short screws with the
three long screw to lock the top cover before shipping the unit.
S-400 Amplifier Owner's Manual
VTL
Re-tubing the VTL amplifier requires the removal
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