Audio Space GALAXY 34 Manual - page 6
6
pre-marked 0.3V point on the lower scale of the meter as shown in the diagram
below.
Repeat the above procedure for each of the output tubes (V1 to V4).
Alternatively, a voltmeter can be used to measure the bias voltage if higher accuracy
is desired. Bias voltage is measured across the +/- test point pair closest to the
selected output tube as marked on the top of the chassis. In this case the “METER
RANGE” knob need not be used. With a small flathead screwdriver, turn the bias pot
of the selected output tube (V1, V2, V3, or V4) until the bias voltage is set at 0.3V.
Repeat the procedure for each of the output tubes.
(VIII) REPLACING VACUUM TUBES
Follow the guidelines below if and when it becomes necessary to replace any vacuum
tube of the amplifier. Be sure to turn off the power and disconnect the power cord
from the amplifier before replacing any vacuum tube.
• Front-end & Buffer Stage tubes (6N9P, 6N8P or 6SL7, 6SN7)
Any of the tubes can be replaced with tubes of the same type or equivalence.
• Output tubes (EL34)
The output tubes should be replaced in pairs. The pair on the left and the pair on
the right should be matched pairs. A matched quad (all 4 tubes) is highly
recommended. Be sure to verify the correct bias voltage afterward.
TROUBLESHOOTING
Basic troubleshooting of an amplifier is similar to troubleshooting of any other
electrical or electronic equipment. Always check the most obvious possible causes
first. The table below contains some common problems, causes, and remedies.
Problem
Cause
Remedy
No power when POWER is
turned on
§
Power plug not inserted
correctly
§
The fuse is shorted out
§
Plug in securely.
§
Replace the fuse with a
new one of the same type.
Soundstage and image seem to
float and not focused
L and R of input or output are
reversed or positive and
negative of speaker terminal is
reversed
§
Reconnect properly
No sound
§
Volume control is set to
minimum
§
Source Selector set to
wrong position
§
Speakers are not connected
§
Wrong input is selected
§
Turn up the volume
§
Check Selector
§
Check speaker cables
§
Check input selection
Background noise too loud
§
Bad signal cable
§
Signal cable, power supply
cord and the video
frequency cable are placed
too close or get tangled up
§
Faulty components or
§
Replace signal cable
§
Re-arrange connections to
good order. Keep signal
cables away from the others.
§
Contact authorized dealer.