Fisher X-100 - Tube Layout; Service Notes; Bias Adjust Control

TUBE LAYOUT |
VOLTAGE AMPLIFIER
HIGH
LEVEL
AND
TAPE
HEAD
AND
AND
PHASE
INVERTER
TONE
CONTROL
AMPLIFIER
PHONO PREAMP.
CHANNEL B CHANNEL A
CHANNEL A CHANNEL B
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CHANNEL
B
CHANNEL
A
POWER
AMPLIFIERS
POWER
AMPLIFIERS
GND 4 °8 16 AUX AUX TUNER CER MAG MAG
7247
SPACEXPANDER
RECTIFIER
CHANNEL B (RIGHT)
| 2 | PHONO 2. 1
B INPUTS L__ 8 inputs-—J
INS-100
SERVICE NOTES
BIAS ADJUST CONTROL
This
control,
located
on
top
of
the
chassis
(see
Tube
Layout),
establishes
the
bias
voltage
on
the
grids
of
the
power
amplifier
tubes
in
each
channel.
Adjust
this
control
as
follows:
1
—
Turn
on
the
power,
leaving
the
Master
Volume
control
at
MINI-
MUM.
The
position
of
the
other
controls
is
not
significant.
2
—
Connect
the
positive
lead
of
a
DC
voltmeter
to
cathode
(pin
#3)
of
any
of
the
power
amplifier
tubes
(V4,
5,
9
or
10,)
and
the
ground
lead
to
chassis
ground.
Turn
the
Bias
Adjust
to
obtain
a
reading
of
+
44
volts
DC.
SERVICE
NOTES
PRINTED IN U.S.A.
©1961 FISHER
RADIO CORPORATION
B4U9—-W12C-111