Thermionic Culture The ULTRA Vulture, Руководство по эксплуатации

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Thermionic Culture Ltd. 2021 9
5 Servicing & Maintenance
5.1 Valves
The unit comes with a 12 month warranty covering all
parts, including valves, and it is essential that it is returned
to our factory or to the dealer from which it was purchased
for repairs to be carried out otherwise the warranty is
invalidated. There is, however, one important exception to
this rule:
Valves are quite delicate items and the most common
cause of failure, despite our choice of highest quality ones.
If
a fault occurs on one channel, a valve is quite likely to be
the cause, so if you feel confident and willing to do the
following, here
’
s the procedure:
Unplug the power and remove the top by undoing screws
which attach it. Note: 1 screw is silver and must be
replaced in the same place. The unit can be powered up
safely without the top on provided that the screening plate
above the circuit board is not removed and reasonable care
is taken not to touch exposed connections, but don
’
t
change valves with the power on! Change over the 2 input
valves. These are the ones with metal screening cans
nearest the left & right sides. If you press down a little and
twist the can anti-clockwise it will come off, then gently pull
out the valve. Be careful when replacing valves that the
pins line up. Do not bend them! Plug back in and see if the
fault has changed sides, if not try changing the next pair
inwards (the
“
distortion” valve). Be sure not to mix up the
valves as they are different types and have different pin
connections!
The valve in the centre is the output valve and is a double
triode common to both channels. This is very robust – the
type 5963 has top marks for reliability. If you want to be
sure, you can replace it with the common ECC82 (12AU7)