Fisher RS 1052 L Service Manual

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(EUROPE)

Thefirst name in high fidelity

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TABLE OF CONTENTS

Specifications ......................................................... 3
Recommended Test Equipment ............................................. 4
Disassembly Instructions .................................................. 5
Exploded View of Cabinet

and Chassis Front Mounted Assemblies ........................................ 6
Exploded View of Chassis _

and Rear Mounted Assemblies .............................................. 7
Parts List ............................................................ 8
Functional Block Diagram ................................................. 9
Dial Cord Stringing ..................................................... 9
AM-FM Multiplex Alignment .............................................. 10

Alignment Wave Forms ..............

AM-FM RF/IF MPX Board Layout ......

RF, IF MPX, P.C.B. Assy Parts List ......

AM-FM RF/IF MPX P.C. Board ........

FM lF IC LA1230 Signal Flow .................................... 13
FM MPX IC LA3350 Signal Flow ..................................

AM RF IF IC HA1151 Signal Flow .......................................... 14
LW/MW Converter P.C. Board ............................................. 15
EOP.C. Board ....................................................... 15
Booster P.C. Board .................................................... 16
Tone Control and Mode Selector P.C. Board .................................. 15, 16
Power Amp P.C. Board ................................................ 17, 18
Power Supply P.C. Board ............ 17
Dial Lamp P.C. Board ................................................... 18
E0, Tone, Boostor. P.C.B. Assy Parts List ..................................... 19
Power Amp, Power Supply, Dial Lamp, P.C.B. Assy Parts List ........................ 20
LW/MW Conv. P.C.B. Assy Parts List ......................................... 20
Power Amp IC STK-084 Schematic .......................................... 20
Point to Point Wiring Diagram Top View .................................... 21, 22
Point to Point Wiring Diagram Bottom View .................................. 23, 24
Schematic Diagram .................................................. 25, 26

EXPLANATION OF PROTECTIVE CIRCUITS

For about two seconds after the power switch is turned on,
the speakers remain silent because the power muting circuit
operates during this time.

If this unit is operated with speakers of 4 ohm or less, or by
being Operated to drive two pairs of speakers of 8 ohm or less
simultaneously, its power limitter will start to operate.

If under these conditions the volume is raised to a high level
the sound from the speakers may be distorted.

* If the speaker terminals are short-circuited or the ventilation
holes at the cabinet top are blocked during long periods of
operation. the internal temperature may rise abnormally.
At about 90°C, the thermal sensor (temperature detection)
circuit becomes activated and will interrupt the signal. If the
cause is removed and the internal temperature is back to
normal, the unit automatically resets itself to restore normal
opration.