Akai AS-8100 User manual

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TABLE OF CONTENTS
SPECIFICATIONS. .......0..:ccceeceeee ee eee tere neta nese ereen ees
I.
DISMANTLING OF AMPLIFIERS ............-:.20::seeeeee
DISPOSITION OF P.C. BOARD
I.
Il.
AS WELL AS CONDENSER OUTPUT ............0:205
TUNER SECTION ADJUSTMENT .............:::cceeeeees
V.
V..
I
0 1
MAIN AMPLIFIER ADJUSTMENT .................00
EPC (ELECTRONIC PROTECTION
VI.
CIRCUIT) ADJUSTMENT ..........ccccceceeeee erent etee ees
DISPOSITION OF EACH ADJUSTMENT
kes
12
14
COMPOSITE VIEWS OF COMPONENTS ..............-+5+
VI.
Vill.
When placing order for parts,
please use separate PARTS LIST.

1. SPECIFICATIONS
An asterisk next to a figure, indicates the minimum guaranteed performance.
AMPLIFIER SECTION
OUTPUT
MUSIC POWER OUTPUT
30 W each channel] at 8 2, 4-channel
60 W each channel at 8 2, 2-channel
RATED POWER OUTPUT
18 W each channel at 8 2, 4-channel
40 W each channel at 8 2, 2-channel
REC. OUTPUT
Din: 25 mV
Pin: 150 mV
INPUT SENSITIVITY
Phono: 3mV
AUx.: 150 mV
Tape 1,2: 150mV
FREQUENCY RESPONSE
20 to 100,000 Hz + 0/-3 dB at 8 2
(20 to 50,000 Hz +0/-1 dB at 8 2*)
POWER BAND WIDTH
20 to 30,000 Hz at 8 2
HARMONIC DISTORTION
Less than 0.1% at 8 2
HUM AND NOISE
-48 dBm
SIGNAL TO NOISE RATIO
Phono: 70 dB (65 dB*)
Aux.: 80 dB (75 dB*)
Tape: 80 dB (75 dB*)
TONE CONTROL
Base: +10 dB at 100 Hz
Treble: +10 dB at 10,000 Hz
LOUDNESS CONTROL
+7 £2 dB at 100 Hz
+4 +2 dB at 10,000 Hz
FILTERS
High Cut Filter: -9 £2 dB at 50 Hz
-6 +2 dB at 10,000 Hz
FM TUNER SECTION
FREQUENCY RANGE
75 to 91 MHz £800 KHz (JAPAN)
87 to 109 MHZ +800 KHz (U.S.A. and S. AFRICA)
IF FREQUENCY
10.7 MHz
SENSITIVITY
Less than 10 dB
HARMONIC DISTORTION
Mono: Less than 0.5%
Stereo: Less than 0.8% (1.0%*)
SIGNAL TO NOISE RATIO
Better than 60 dB
SELECTIVITY
Better than 60 dB (40 dB*)
IMAGE INTERFERENCE RATIO
Better than 100 dB (80 dB*)
IF INTERFERENCE RATIO
Better than 100 dB (90 dB*)
CAPTURE RATIO
Better than 1.5 dB (2 dB*)
SPURIOUS RATIO
Better than 34 dB
MUTING SENSITIVITY
20 +3 dB
SCA INTERFERENCE RATIO
Better than 50 dB
SEPARATION
Better than 35 dB
ANTENNA INPUT IMPEDANCE
300 2 balanced; 752 unbalanced
AM TUNER SECTION
FREQUENCY RANGE
525 £5 KHz to 1630 +15 KHz
IF FREQUENCY
455 KHz
SENSITIVITY
Dummy: Less than 15 dB
Loop: Less than 46 dB
HARMONIC DISTORTION
Less than 1.5%
SIGNAL TO NOISE RATIO
Better than 50 dB (40 dB*)
SELECTIVITY
30 dB (20 dB*)
IMAGE INTERFERENCE RATIO
Better than 70 dB
IF INTERFERENCE RATIO
Better than 70 dB
TRANSISTORS USED
4 .....2SA545 (M) 2 .....28C535
5 .....28C838 (H) 8 .....28C853 (M)
12.....2SC900 (F, H) 3 .....28C945 (R)
1 .....28C968 (3) 2 .....28C1014 (D1, D2)
8 .....28D313 1 .....SE3001
FET USED:
1.....28K30
IC USED:
2....LALI11
6.....LD3120
1.....A3300
DIODES USED
6 .....IN34A 4 .....1N60
8.....10D1 1.....5B2
1....1RCS Fees 1S337A
4....VD1211
THERMISTORS USED:
4.....23D29
POWER SUPPLY
100 V to 240 V AC, 50/60 Hz
U.S.A.: 117 V AC, 60 Hz as per U/L
POWER CONSUMPTION
200 W
DIMENSIONS
487(W) X 165(H) X 346(D) mm (19%" X 7" X 14%")
WEIGHT
16 kg. (35.3 lbs.)

ll. DISMANTLING OF AMPLIFIERS
In case of trouble, etc. necessitating disassembly, please
disassemble in the order shown in photographs.
Reassemble in reverse order.
UPPER COVER
LOWER COVER

i. DISPOSITION OF P.C. BOARD AS WELL AS
CONDENSER OUTPUT
EQUALIZER AMP. oy op ‘ mon |
P.C. BOARD —. ‘ ‘ coat AM IF AMP.
P.C. BOARD
MPX AMP.
P.C. BOARD
: 2a: FRONT END
: awe ns (TUNER)
FM IF AMP. : bya : oe
P.C. BOARD i). es :
MAIN AVE
P.C. BOARD a
POWER
TRANSFORMER
POWER
TRANSFORMER
PHASE INVERTER
POWER SUPPLY
AMP. P.C. BOARD
P.C. BOARD
TONE CONTROL
AMP. P.C. BOARD
VOLUME CONTROL
P.C. BOARD

IV. TUNER SECTION ADJUSTMENT
1.
TERMINATION PAD
(MODEL 2151-8)
FM IF CIRCUIT ADJUSTMENTS
(See Figs. 1 and 2)
FM IF PC.
BOARD
2).
3)
4)
5)
AM-FM RADIO IF GENESCOPE
(MODEL MSW~721C)
Fig. 1
10.7 MHz
Fig. 2
Adjust V-Gain Volume to obtain a 2 cm amplitude
of 0.3V p-p AM FM Radio IF Genescope cali-
bration voltage on screen and set Genescope
Cutput to 50 dB.
Connect Genescope Output to point (1) (FM IF
Input), and Genescope Input to point (8) (AF
Output).
Set Mode Switch to “FM” and set dial to about
109 MHz reception frequency.
Adjust the upper core of IFT “L,” of FM IF
Amp. P.C. Board so that the S Curve output
voltage is maximum. Also adjust the lower core to
obtain optimum S Curve linearity.
In making this adjustment, in some cases the rank
of the ceramic filter causes a discrepancy in the S
Curve Marker Point, but it is satisfactory if
through adjustment a margin of within +500 Hz
can be obtained (See Fig. 3).
Ceramic Filter Rank
Center Frequency | Error Tolerance
10.60 MHz
10.65 MHz
10.70 MHz
10.75 MHz
10.80 MHz
as
2)
3)
4)
COLOR MARK
CERAMIC FILTER
Fig. 3
FRONT END AND FM IF MATCHING
ADJUSTMENT (See Fig. 6)
IF COIL (Front end) Fig. 4
Fig. 5
Adjust V-Gain Volume to obtain a 2 cm amplitude
of 0.3V p-p AM FM Radio IF Genescope cali-
bration voltage on screen, and set Genescope
Output to 90 dB.
Connect Genescope Output to 3002 impedance
FM Antenna Terminal, and Genescope Input to
Terminal (8) (AF Output) of FM IF P.C. Board.
Set Mode Switch to “FM” and set the tuning
indicator to the right end of the dial.
Adjust the upper core of IF Adjustment Core in
front end so that the value of the S Curve wave
height is maximum. Then adjust the lower core so
that the noise element is maximum and the upper
and lower reaches of the scanning line are the same
level (See Figs. 4, 5 and 7).

3.
1)
2)
AS-8100
TERMINATION PAD
bY
LA]
INPUT OUTPUT
(MODEL 2151-8)
<<. _ ~ AM-FM RADIO IF GENESCOPE
(MODEL MSW-72IC)
Fig. 6
© 66 66
AM AM AM tS
= jae
LO IF -LR2 LRI LA
(
TOP
VIEW
OF
FRONT
END
Fig.
7
AS-8100
-_ +O, nomen ye)
OUTPUT 30020 LCH : INPUT
O-— —~ SPEAKER ~+——-O
FM ANTENNA OUTPUT 80 45W
TERMINATION PAD INEUT
(MODEL MR-200)
FM SIGNAL GENERATOR DISTORTION METER
(MODEL MSG-278G) (MODEL 750C)
. Fig. 8
FM RECEPTION FREQUENCY RANGE
ADJUSTMENT (See Figs. 7 and 8).
Connect the FM Signal Generator Output to the
3002 impedance FM Antenna Terminal of Model
AS-8100 through the termination pad. Introduce
an 882 45W dummy load resistor to the left
channel speaker output and connect a distortion
meter to this output. At this time, with speaker
output at 10 dB, set Speaker Surround Balance
Shift to Front/Left position.
Set the FM Signal Generator to 90 MHz (400 Hz,
30% internal modulation and the output to 90 dB.
4)
5)
6)
Adjust the core of Oscillator Coil “Lo” of FM:
Local Oscillator in front end so that the distortion
meter level is maximum and the distortion factor
is minimum,
Set the tuning indicator to the right end of the
dial. Set the FM Signal Generator frequency to
106 MHz.
Adjust Trimmer Condenser **TCO” in front end so
that the distortion meter level is maximum and the
distortion factor is minimum.
Repeat items 2) through 5) two or. three times
until perfect reception is obtained in the reception
frequency range of 87 to 109 MHz.

4.
OUTPUT
TERMINATION PAD
{MODEL MR-201I0) TERMINAL
FM SIGNAL GENERATOR
(MODEL MSG-2786)
DISTORTION METER
| OSCILLOSCOPE
- (MODEL 760C)
Fig. 9
fs
FM TUNER TRACKING ADJUSTMENT
(See Figs. 7 and 8)
Use the same instruments as in item 3 (Fig. 8) and
connect them in the same way.
1)
2)
4)
5)
Set the FM Signal Generator frequency to 98 MHz
(400 Hz, 75% internal modulation) and the output
to 16 dB.
Set the Tuning Dial to receive the 98 MHz signal.
Adjust core “IF’’ of coil in front end so that the
distortion meter level is maximum and the dis-
tortion factor is less than 0.3%.
Set the FM Signal Generator frequency to 106
MHz and set the tuning dial to receive the 106
MHz signal. Adjust Trimmer Condensers “TCA”,
“TCR 1” and “TCR 2” in the front end so that
the distortion meter level is maximum and the
distortion factor is less than 0.3%.
Set the FM Signal Generator frequency to 90 MHz
and set the tuning dial to receive the 90 MHz
signal. Adjust cores “LA”, “LR 1” and “LR 2” in
front end so that the distortion meter level is
maximum and the distortion factor is minimum.
Repeat items 1) through 4) two or three times
until perfect tracking and maximum reception
sensitivity is obtained at 90 MHz, 98 MHz, and
106 MHz.
Note: When the distortion factor is 0.3%, the generator
3.
1)
output level is less than 16 dB.
MUTING SENSITIVITY ADJUSTMENT
(See Figs. 9 and 10)
Set the Signal Generator output level to 26 dB (+3
dB) and connect this output to the FM Antenna
Terminal of Model AS-8100 through the termi-
nation pad, and connect the vertical input of the
Oscilloscope as well as the distortion meter input
-to Terminal (8) (AF Output) of AM IF PC. Board.
3)
4)
2)
4)
Fig. 10
Turn Muting Level Adjustment Semi-Fixed Re-
sistor VR-1 (68 KB) in FM IF P.C. Board fully
clockwise and set FM Mute Lever to “Off”
position.
Turn semi-fixed resistor VR-1 counter-clockwise
to position at which Oscilloscope sine wave-
form is completely erased (do not turn beyond
this point).
If in this waveform erasing process, the waveform
is not erased and appears as in Fig. 10, the mute
circuit is defective. .
If perfect adjustment cannot be made by adjusting
muting sensitivity volume VR-1, because this is
due to poor alignment of Coil ““L,” (05M-755), in
the mute circuit, adjust the core of “L,” for
improved mute circuit sensitivity.
TUNING INDICATOR CHECK AND
DISTORTION ADJUSTMENT
Use the same instruments as in Section 5 (Muting
Sensitivity Adjustment) and connect them in the
same way.
Set the FM Signal Generator Output to 66 dB, and
connect this output to the FM Antenna Terminal
of Model AS-8100 through the termination pad.
Connect the Oscilloscope Vertical Input as well as
the Distortion Meter Input to Terminal (8) (AF
Output Terminal) of FM IF P.C. Board.
Set the FM Signal Generator frequency to 98
MHz, and set the tuning dial of Model AS-8100 to
the same 98 MHz frequency.
Adjust the upper core of “Ly” (O05M-775A) so
that the tuning indicator needle is centered, and
adjust the lower core of “L,” to obtain the least
distortion.

FM STEREO FM SIGNAL
MODULATOR GENERATOR
(MSG- 2110) (MSG -278G)
OUTPUT
TERMINATION PAD
AS-8100
SPEAKER
(MODEL 2151B)
7. SEPARATION ADJUSTMENT
1)
2)
3)
4)
5)
6)
(See Fig. 11)
Set the FM Stereo Modulator Pilot Signal 19 KHz
to 10% modulation and the main signal (L + R) to
400 Hz, 90% modulation. Connect this composite
signal (ratio 9:1) to the EXT MOD Terminal of the
FM Signal Generator.
Set the FM Signal frequency to 98 MHz and set
this output level to 66 dB, and connect to the FM
Antenna Terminal of Model AS-8100.
Connect a high sensitivity V.T.V.M. or an 8Q
more than 45W dummy load resistor to the various
speaker output terminals. Set Tone Control to
“Flat” position and then set the tuning dial to 98
MHz and speaker output to 20 dB.
Turn Separation Adjustment Volume VR-3 (1 KB)
fully clockwise. Set the FM Stereo Modulator to
right channel, and adjust the cores of “L,” and
“L,” coils so that the indication of V.T.V.M.
(connected to left channel) is minimum. Then turn
VR-3 counter-clockwise to position at which the
V.T.V.M. indication is minimum.
Set FM Stereo Modulator to left channel and
adjust the cores of “L,” and “L,” so that the
indication of V.T.V.M. (connected to right chan-
nel) is minimum. Then adjust VR-3 so that the
V.T.V.M. indication is minimum.
If separation is not better than 35 dB, repeat the
above adjustments again. Avoid turning the coil
cores too much when making this second adjust-
ment.
If the FM Signal Generator output has been
decreased to 26 dB (+3 dB), check to see whether
the stereo indicator lamp has been extinquished.
8.
1)
2)
3)
4)
OUTPUT (MODEL 164)
V.LV.M.
Fig. 11
"AM-FM RADIO IF GENESCOPE
(MODEL MSW-72IC)
Fig. 12
AM IF CIRCUIT ADJUSTMENT
(See Figs. 12 and 13)
Adjust the V-Gain Volume to obtain a 2 cm
amplitude of 0.3V p-p AM FM Radio IF Gene-
scope calibration voltage on screen, and set the
Genescope output to 60 dB.
2cm
pr een Fig. 13
Connect Genescope output to Test Point (TP) and
Genescope Input to Point (8) (AF Output).
Set Mode Switch to “AM” and reception fre-
quency to about 1630 kHz.
Adjust cores of IFT, T,;, T,, and T,; of AM IF
Amp P.C. Board so that the waveform (Fig. 13)
level is maximum and center frequency is 455 kHz
(Center frequency differs according to country.
Adjust according to country’s center frequency).

9.
1)
2)
3)
4)
5)
6)
OUTPUT
TERMINATION PAD
(MR-2010)
AS-8100
EXT AM
ANTENNA INPUT
L-CH an 45w
SPEAKER
OUTPUT
AM SIGNAL GENERATOR
(MSG-230E)
AS-8100
TERMINATION PAD
(MR-2010)
DISTORTION METER
(MODEL 760C)
Fig. 14
AM SIGNAL GENERATOR
(MSG -230E)
AM RECEPTION FREQUENCY RANGE
ADJUSTMENT (See Fig. 14.)
Connect the AM Signal Generator output to the
EXT AM Antenna input terminal of Model AS-
8100 through the termination pad. Introduce an
8Q more than 45W dummy load resistor to the
left channel speaker output and connect a dis-
tortion meter to this output. At this time, set
speaker output level to 10 dB and the Surround
Balance Shift to Front/Left position.
Set the tuning indicator to the left end of the dial.
Set the AM Signal Generator frequency to 525
kHz (+5 kHz), (400 Hz, 30% modulation) and the
output to 70 to 80 dB.
Adjust the core of AM Local Oscillator Coil “L”
(094-465) in the AM IF P.C. Board so that the
distortion meter level is maximum and the dis-
tortion factor is minimum.
Set the tuning indicator to the right end of the
dial. Set the AM Signal Generator frequency to
1530 kHz (£5 kHz).
Adjust Trimmer Condenser “TC3” in front end
block so that the distortion meter level is. maxi-
mum and the distortion factor is minimum.
Repeat adjustments outlined in items 2) through
5) above two or three times until perfect reception
is obtained in the reception frequency range of
525 to 1530 kHz.
2)
3)
4)
5)
6)
7)
8)
DISTORTION METER
(MODEL 760C)
Fig. 15
AM TUNER TRACKING ADJUSTMENT
(See Fig. 15)
Connect the Signal Generator output to the AM
input point of Mode! AS-8100 through the termi-
nation pad. Introduce an 882 more than 45W
dummy load resistor to the left channel speaker
output and connect this output to the distortion
meter input.
At this time, with speaker output level at 10 dB,
set Speaker Surround Balance Shift to Front/Left
and Tone Control] to “Flat” position.
Set the AM Signal Generator frequency to 1400
kHz (400 Hz, 30% internal modulation) and the
output to 21 dB. Set the tuning dial to receive the
1400 kHz signal.
Adjust Trimmer Condensers “TC 1” and “TC 2”
in the front end so that the distortion meter level
is maximum and the distortion factor is minimum.
Set the AM Signal Generator frequency to 600
kHz and set the tuning dial to receive the 600 kHz
signal.
Adjust the core of coil “L,” (05M-741 A) in AM
IF P.C. Board as well as core of the Bar Antenna
so that the distortion meter level is maximum and
the distortion factor is less than 10%.
Set the AM Signal Generator frequency to 1,000
kHz and set the tuning dial to receive the 1,000
kHz signal.
Check to confirm that the distortion meter level is
maximum and the distortion factor is less than
10%.
Repeat items 2) through 6) above two or three
times until perfect tracking is obtained at these
three frequencies.
Note: When the distortion factor is 10%, the Generator
output level is less than 21 dB.