Marantz 1090 User manual

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TABLE OF CONTENTS
SECTION PAGE
1s INFRODUCTION) 2:2 hed eet 4 ae PERE ON GNA Maia wee Siac? eee aeRO ees Sek 1
22: PRE-AMPLIBUER: cc. < hse cies ca beter gy ee 8 Ook oi le ee Si a iw hs Mit ete eg ee LAG. ete ea’s 1
3.7 MAIN (AMPLIFIER: c5.ccocceaea elise scaateasdeecas tin ends 8 Os reie OW 6 de wel a. os 9S aoa a Aad Rhee See Ae a 1
4. TROUBLESHOOTING ANALYSIS ......... 0... ccc cece cee eee eee eee eee e eee e nena 1
5. POWER AMPLIFIER ADJUSTMENT ......... 0... . ccc ee teens eee e een neneaee 1
6. TEST EQUIPMENT REQUIRED FOR SERVICING ........... 0... 0c ccc cece ee eee eens 2
7. PERFORMANCE VERIFICATION ......... 0.0... cc ccc cee te ee ee eee eee n ee ee eennaee 2
8. VOLTAGE. CONVERSION 36.5 itnd sek 0.6 wore nies Gwate Ouse VAww eA et hawt wee oe eee 5
8:1 Voltage Conversion: Chart. -2:ccie:ei ccc eect anda wa ee Madar wad, Sees ad ese arare aitansaha ek, Sie Giver els Bea tee 5
9, MAJOR COMPONENT LOCATIONS ........ 0... ccc cee cece eee eee ene eeenanae 6
9.1 Front Panel Adjustment and Component Locations ..... 0... cece eee ee ee eee ee eee enna 6
9.2 Main Chassis Component Locations (Top View) ....... ccc cence eee eee cece ec eeeennnetnvenes 6
9.3 Rear Panel Adjustment and Component Locations ..... 0... 0. cc eee ee ee eee eee een e anne 7
9.4 Main Chassis Component Locations (Bottom View) ........ cc eee eee ee ee eee ee ee ee tence nnn 7
10. DIAGRAM AND COMPONENT LOCATIONS ........ 0... ccc cee eee eee een ee 8
10.1. Tone Component Assembly (PFO1) Schematic Diagram and Component Locations .........0.ee eee eee 8
10.2 Rear Panel Assembly (PVOO) Schematic Diagram and Component Locations .........0.0ce eee ee eaae 9
10.3 Speaker Switch Assembly (PSO1) Schematic Diagram and Component Locations .......eee eee eeeees 10
10.4 Pre-Amp. Assembly (P400) Schematic Diagram and Component Locations ........ cece eee eect eeaee 11
10.5 Main Amp. Assembly (P700) Schematic Diagram and Component Locations .........0cececeeuecees 13
11. CONNECTION DIAGRAM .......... ee ee ee ene eee neta een neenans 15
12. SCHEMATIC DIAGRAM «3 occ eee eee cee er ee aa band ode ep eine es eu eee ee dees aes 17
13. EXPLODED MECHANICAL DIAGRAM ........... 0... ccc cece ee eee eee nent e eee e nes 19
14. PACKING MATERIAL EXPLODED VIEW ............ 0... ccc ccc cece cece ee ee eee e enn ennes 22
15: BLOCK: DIAGRAM. .¢ s:icse¢ o(e08 ett we Pe ie whe dian eae aoe daa gate Ha ak WE Se WE Bea des Bares 23
163 PARTS: LIST) os beets Seed wieatat Beste Aion suck we OF ale Recede damier binds Ber 24
17. TECHNICAL SPECIFICATIONS

1. INTRODUCTION
This service manual was prepared for use by Authorized
Warranty Stations and contains service information for
the Marantz Model 1090 Stereo Console Amplifier.
Servicing information and voltage data included in this
manual are intended for use by knowledgeable and expe-
rienced personnel only. All instructions shouid be read
carefully. No attempt should be made to proceed without
a good understanding of circuitry operation.
The parts list furnishes complete ordering information.
Most replacement parts should be ordered from the
Marantz Company. However, a simple description is
included for parts which can be obtained locally.
2. PRE-AMPLIFIER
Signals from the input jacks (TUNER, AUX, TAPE 1
& TAPE 2) are applied to the selector switch.
Signals from the PHONO 71 and PHONO 2 jacks are
applied to the other section of the selector switch, then
to the phono-amplifier and equalized for proper frequen-
3. MAIN AMPLIFIER
The main amplifier consists of differential pre-amplifiers
Q701 and Q703, class ‘A’ driver Q707, Q709 and direct-
coupled drivers Q717 and Q719.
Q713 and O715 act as current limiters.
cy response. The gain of the phono-amplifier (Q401,
Q403 and Q405) is 40dB.
The outputs of the phono-amplifier are fed to the selector
switch. The selector switch selects one of signals from
PHONO 1, PHONO 2, TUNER, AUX, TAPE 1, TAPE 2
jacks and feeds it to the TAPE MONITOR switch and
TAPE OUT jacks. The selected signal is then applied to
the MODE switch, to the balance and volume controls,
and finally to the pre-amplifier consisting of QEO1,QE03,
QE05 and QE07.
The frequency response is controlled by the Bass, Middle
and Treble controls and the resultant output is passed
to the PRE OUT jacks through the High-cut filter net-
works. These networks are switched in and out of the
circuit by the filter switches.
4. TROUBLESHOOTING ANALYSIS
1. Excessive line consumption
a. Check for shorted 0801, through 0804.
b. Check for shorted transistor HOO1, through HO04.
c. Check for open HOO5, HOO6, R733, R734.
2. No line consumption or zero bias voltage
a. Check line cord, fuse, check for shorted H005,
HO06, R733, R734.
b. Check for open rectifiers Q801, Q802 or open
L001.
3. High hum and noise level
a. Check filter capacitors C809, C810, C803, C807.
4. Parasitic oscillation
a. Check C707, C708, C709, C710, C727, C728.
5. POWER AMPLIFIER ADJUSTMENT
ADJUSTMENT OF IDLING CURRENT
Connect a vacuum voltmeter to between emitters Q721
and 0723. Adjust R771 until 12 mA is reached, Likewise,
adjust Q724, Q722 and R722.

6.
TEST
EQUIPMENT
REQUIRED
FOR
SERVICING
Line
Switch
OFF
Variable-line
switch
Variable
Table
1
lists
the
test
equipment
required
for
servicing
the
Wattmeter
Switch
ON
Mode!i
1090
Stereo
Console
Amplifier.
The
wattmeter,
Variable
Autotransformer
0
V
(fully
CCW)
AC
voltmeter,
and
variable
autotransformer
may
be
assem-
Load
8 ohms
(0.5
mfd
—
OFF)
bled
as
a
test
fixture
as
shown
schematically
in
Figure.
Audio
Generator
1kHz
The
load
resistors
and
AC
ammeter
may
be
assembled
into
Output
5
V
range
a
second
test
fixture
as
shown
in
Figure
2.
Gain
Minimum
AC
VTVM
30
V
range
7. PERFORMANCE VERIFICATION
2. Make sure that connections between the resistive
TEST PROCEDURE load and the system terminals of the Model 1090
have negligible resistance when compared with the
A. TEST EQUIPMENT resistance of the load itself. Appreciable resistance
Refer to Table1 for required test equipment. in wiring adds to the total load, resulting in inaccu-
rate measurements of output power.
B. PRELIMINARY PROCEDURES xe
3. Connect amplifier output to load and connect AC
1. Make the test setup shown in Figure 1 with the cord to line power. Connect shorting plugs to the
instrument controls set in the following positions: Phono input jacks of the Model 1090.
Table 1. Test Equipment Required for Servicing
Item Manufacturer and Model No. l Use
\ ss S = eee oer
Distortion Analyzer Distortion measurements
Audio Oscillator Sound Technology Model 1700B Sinewave and squarewave signal source
AC VTVM voltage measurements (AC}
. Tektronix Model T932 Waveform analysis and trouble shooting and
Oscilloscope i F
Philips Model 3232 ASO alignment
Circuit Tester a ad —- : Trouble shooting
‘ Fluke Model 8000 “Digital” Simpson
M Voltage measurements (DC
Oey Model 313, Triplet Model 801 pe
AC Wattmeter lr. Simpson Model 1379 _ Monitors primary power to amplifier
{ pee es ppeerllen. ee . 4
Moni ifi ircui
ReReameter Conmercial Graded S10-A) OGiEOTs armel: ier output under short circuit
condition
= ae 1 nee ate St Sete os ast a
Moni ; :
Line Voltmeter Simpson Model 1359 SPuOlS Potential OR PU Maly BOWEr TO
amplifier
ae
|
shan
|
Superior Electronic Co., . . fat
Variable Autotransformer Pee Model 116B-10A Adjusts level of primary power to amplifier
l . > Use phono plug with 600 ohm i Shorts amplifier input to eliminate noise
Shorting Plug . :
across center pin and shell pickup
Output Load Conaiarsial Grade Provides 8-ohm load for amplifier output
(8 ohms, +0.5% 100 W) termination
t Load Provides 4-ohm load for amplifier output
Commercial Grade
(4 ohms, 0.5% 100 W) termination
Output Load Capacitor Mytar Provides capacitive load for instability checks
(0.5 mfd)
AC ve Goal Bax Optional Item. Rabricate in Monitors and controls primary power for
accordance with Figure 1 amplifier
upline Outaue bakBox Optional Item. Fabricate in Provides various amplifier loads and can
accordance with Figure 2 monitor shorted output

105 TO 125VAC
50/60 Hz
l- LINE SWITCH
SLO-BLO
VARIAC
VARIABLE
OQ
AC OUTLETS
AC WATTMETER
0 TO 150 WATTS
AC VOLTMETER
0 TO 150VAC
Figure
1.
AC
Power
Control
Box
Simplified
Schematic
,
(MOMENTARY
SWITCH)
O
AC AMMETER
QO TO 10 AMPERES
oO
INPUT OUTPUT
GRD
{GRD
Figure 2. Amplifier Output Load Box Simplified Schematic

TOTAL HUM AND NOISE TEST
With shorting plugs connected to the Phono input
jacks and an 8 ohm resistive load connected across
HARMONIC DISTORTION TEST
. Set the frequency of the audio oscillator and the
distortion analyzer to 20 kHz.
the speaker system output terminals, connect a dis- 2
; . Set the controls of the analyzer for voltage measure-
tortion analyzer across the load.
ment on the 30 volt scale.
NOTE: 3. Adjust the audio oscillator output level until the
analyzer meter indicates 16.8 VAC.
If the distortion analyzer does not contain a built-in volt- 4
meter, an AC VTVM may be substituted.
. Switch the distortion analyzer to Set Level and
adjust SENSITIVITY for full scale readingon O~ 1%
scale.
Set the distortion analyzer controls for voltage 5
measurements and apply power to the amplifier.
Set the volume contro! fully CCW. Set the
SELECTOR switch to PHONO.
. Measure the total harmonic distortion with the
analyzer and verify it is less than 0.1%.
3. If the distortion analyzer indicates more than 2.0 mV, NOTE:
refer to the trouble analysis section of this manual.
Any parasitic oscillation in the amplifier will be displayed
on the oscilloscope when capacitance is switched into
the load.
4. Set the volume control fully CW. If the distortion
analyzer indicates more than 20 mV, refer to the
trouble analysis section of this manual.
MAXIMUM POWER OUTPUT
Connect the audio oscillator to the AUX input. Set
. Switch the distortion analyzer back to SET LEVEL.
(Do not readjust sensitivity of analyzer.)
audio oscillator frequency to 1 kHz. Set SELECTOR 7. Change the frequency of the audio oscillator and dis-
switch to AUX. tortion analyzer to 1 kHz. Adjust audio oscillator
j ~ Q
With the distortion analyzer connected across the GURUS fOr ¢. ull <seale Neading onthe O ~cle-scale:
output load (8-ohm), set the analyzer on the 30 VAC 8. Measure the distortion, verifying it'is no greater than
scale. 0.1%.
Turn the analyzer on and increase the audio oscillator 9. Repeat steps 7 and 8, changing frequency to 20 Hz.
output to 180 mV. The AC VTVM should read 16.8 Distortion should be no more than 0.1%,
VAC : an :
i 10. Check for parasitic oscillation; there should 9e none.

@ EUROPEAN MODEL ONLY
8. VOLTAGE CONVERSION
This Model is equipped with a universal power transform-
er to permit operation at 110, 120, 220 and 240 V AC CAUTION
50/60 Hz.
DISCONNECT POWER SUPPLY CORD FROM AC
To convert the unit to the required voltage, set the piug as OUTLET BEFORE CONVERTING VOLTAGE.
illustrated so that you can adjust the voltage as required.
8.1 Voltage Conversion Chart
For 110V Operation
For
120V
Operation
For
220V
Operation
For
240V
Operation

9. MAJOR COMPONENT LOCATIONS
9.1 Front Panel Adjustment and Component Locations
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9.3
Rear
Panel
Adjustment
and
Component
Locations
SPEAKER SYSTEMS:
CRUTION #1 \eUED
YECTION AGAINST FIRE HAZ
REPLACE GALY WITH SAME TYPE
SS AMP 2500 FUSE
——
3005
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10. DIAGRAM AND COMPONENT LOCATIONS
10.1 Tone Component Assembly (PF01) Schematic Diagram and Component Locations
RFO2 22k 100k RFO4 22k
CFO! CFOS
0.015 9.015
50V iv
8
1
T
8
RF20
cFr12 e-{ Fe