Fisher 80 T Service Manual

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THIS FISHER

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FM -AM TUNER

INSTALLATION, OPERATING
AND SERVICE INSTRUCTIONS

MODEL 80-T

PRICE: $1.00

FISHER RADIO CORPORATION NEW YORK

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FISHER

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FM-AM TUNER

MODEL 80-T

GENERAL INFORMATION
THE FISHER FM-AM Tuner, Model 80-T is

designed to meet the requirements of the most
exacting user, having been planned to profession-
al standards from its inception. Despite its full
complement of tubes and components the 80-T
features an unusually compact chassis of fine
design. It incorporates a two-band superhetero-

dyne circuit with completely independent RF
channels for FM and AM.

The FM section comprises a dual triode, cascode,
tuned RF stage (for maximum signal-to-noise
ratio) and two IF stages followed by two
cascaded limiters. These are combined with a
Foster-Seeley discriminator to produce a genuine
Armstrong system, universally recognized as the
ultimate in FM receivers. The Automatic Fre-
quency Control (AFC) on FM assures accurate
tuning and freedom from drift. The range of
lock-in is adjustable from. the front panel. It
features a separate tuning meter for FM and dual
antenna inputs: 72-ohm or 300-- -ohm balanced.

A tuned RF stage and two adjustable band width
IF stages are incorporated in the AM section.
Because of the adjustable band-width, selectivity
can be varied to achieve the maximum fidelity
possible under the reception conditions prevailing
at the time. The diode detector has been designed
for minimum distortion under all operating
conditions. A sharply tuned 10 Kc filter has been
incorporated for rejection of adjacent channel
heterodyne whistle. Dual antenna inputs on both

__...

A." . . . .
AM and FM afford max1mum flex1b111ty 1n
antenna matching. A professional-type AM tun-
ing meter permits micro-accurate tuning on AM.

A carefully designed flywheel tuning mechanism,
equipped with an anti- backlash gear, makes
selection of stations extremely simple and smooth.
The edge-lighted glass slide-rule scale has large,
easy-to-read numerals as well as a 0 to 100 log-
ging scale for convenient spotting of the stations
most frequently used. The front panel of the
Model 80-T is a handsome brushed-brass fascia

that adds distinction to any group of equipment.

A second integrated chassis houses all of the
audio and preamplifier stages. A dual VOLUME
Control with an optional LOUDNESS position
assures maximum signal-to-hum ratio, regardless
of the setting of the Control. Both RECORDER and
MAIN amplifier Outputs are of the cathode fol-
lower type to provide independence from output
load characteristics and cable lengths. The
RECORDER Output does not include the use of

M'TONE Controls or VOLUME LOUDNESS Control

for use in recording applications or where a
second remote control chassis is to be used.

A complete phonograph and tape preamplifier
for low-level magnetic cartridges and direct tape
head playback is included in THE FISHER
Model 80~T and provides six separate and com-
plete record equalization settings to accommodate
all of the popular records manufactured. There
is also a correctly equalized setting for the
standard NARTB tape playback characteristic.