Akai GXC-570D Troubleshooting guide

SERVICE MANUAL
PARTS LIST
MODEL
GAC
_
OD

CASSETTE STEREO TAPE DECK
voor. GXC-570D
* SECTION 1 SERVICE MANUAL......................... 3
SECTION 2 PARTS LIST .............................. 4
SECTION 3 SCHEMATIC DIAGRAM...................... 64
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SECTION 1
SERVICE MANUAL
TABLE OF CONTENTS
TECHNICAL DATA: scien su cles ser stig oa aoe wees 4
DISMANTLING OF UNIT 2255.5/2043, se ee Ge Seca deecees 5
PRINCIPAL PARTS LOCATION ..........0-20-0002ecceeeeeeeee 7
CIRCUIT OPERATING PRINCIPLES .............. Pp snse. cateret 8
1. SYSTEM CONTROL OPERATION ..........-2--2002002000- 8
2. TOUCH BUTTON SYSTEM OPERATION ............-2.-2-5- 12
MECHANISM ADJUSTMENT .........---2--20200 ccc eee eee 14
1. CAPSTAN SHAFT LOOSE PLAY ADJUSTMENT ”............-- 14
2. MOTOR PULLEY INSTALLATION POSITION ADJUSTMENT ..... 14
3. REEL TABLE INSTALLATION POSITION ADJUSTMENT ........ 14
4. PINCH ROLLER PRESSURE ADJUSTMENT ...............-- 15
5. PLAY SOLENOID INSTALLATION POSITION ADJUSTMENT ..... 15
6. ADJUSTMENT OF EJECT MICRO SWITCH ACTUATION POSITION. 16
7. ADJUSTMENT OF RECORDING MICRO SWITCH (SW3) AND
CASSETTE MICRO SWITCH (SW6) ACTUATING POSITION .. 16
8. REEL MOTOR (GSM-300) REPLACEMENT ..........--.--+-- 17
9. FRONT PANEL LID CASE SPACING ADJUSTMENT ........... 17
10. POSITION ADJUSTMENT OF LID CASE ............-----0-- 18
11. CLEARANCE ADJUSTMENT BETWEEN HALL IC AND
ROTARY MAGNETS: 9609 aden bogs cry eae ewevsaues 18
HEAD ADJUSIMEND ©. 2..6.044 4 222i o$vass ow ee eae kee twas 19
1. TAPE GUIDE HEIGHT ADJUSTMENT..........-...-2..-05- 19
2, . HEIGHT ADJUSTMENT OF RECORDING/PLAYBACK
COMBINATION HEAD...........--200-0005- uasaes 19
3. AZIMUTH ALIGNMENT ADJUSTMENT OF
RECORDING/PLAYBACK COMBINATION HEAD.......... 19
AMPLIFIER ADJUSTMENT ...........-0 02002002 cece eee ee ee 20
1. RECORDING/PLAYBACK AMPLIFIER ADJUSTMENT .......... 22
2. DOLBY NOISE REDUCTION CIRCUIT ADJUSTMENT .......... 23
3. RECORDING DOLBY NOISE-REDUCTION AMPLIFIER
JADTUSTMENT scx S4 cieonca wi tone a a8 Marmara oz 23
4, PLAYBACK DOLBY NOISE REDUCTION AMPLIFIER
ADJUSTMENT ...........-..-- sens Dease eases 23
DC RESISTANCE OF VARIOUS COILS ...... 2.222200 -0 002 eee ee 24
CLASSIFICATION OF VARIOUS P.C BOARDS ..........-...--.+- 25
1. RELATION OF VARIOUS P.C BOARDS TITLE AND. NUMBER ..... 25
2. COMPOSITION OF VARIOUS P.C BOARDS ....... wseuiated, gush sew rea 26
For basic adjustments, measuring methods, and operating principles, refer to GENERAL OPERATING
PRINCIPLES AND ADJUSTMENTS. ;
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|. TECHNICAL DATA
TRACK SYSTEM
4 track 2 channel stereo system
TAPE Philips type cassette
TAPE SPEED 1-7/8 ips (Pitch Control +5%) =e
WOW AND FLUTTER Less than 0.06% WRMS
Less than 0.17% (DIN 45500)
FREQUENCY RESPONSE
. 30 Hz to 19,000 Hz (+3 dB) using Fe-Cr tape -
30 Hz to 15,000 Hz (+3 dB) using low noise tape
30 Hz to 16,000 Hz (+3 dB) using C,O, tape
DISTORTION Less than 1% (1,000 Hz “0” VU) using low noise tape
SIGNAL-TO-NOISE RATIO Better than 52 dB (measured via tape with peak recording level of +5 VU)
Dolby Switch ON: Improves up to 10 dB above 5 kHz g
ERASE RATIO Better than 70 dB ‘
BIAS FREQUENCY 100 kHz :
HEADS GX recording/playback head and erase head (3 head system)
MOTORS One AC Servo outer rotor motor for capstan drive and two DC motors
for reel drive
FAST FORWARD AND REWIND TIME 60 to 80 seconds (variable) using 4 C-60 cassette tape
OUTPUT JACKS Line (2): 0.775V (0” VU)
Required load impedance: More than 20 k ohms’
Phono (1): 50 mV/8 ohms ies.
INPUT JACKS = Microphone (2): 0.3 mV
ae Required microphone impedance: 600@’ohms -
Line (2): 70 mV/100 k ohms
TRANSISTOR 2SA628 (E) (F) .....-....--- 3 -
2SB605 (K) (L) ..........:-. 2
2SC458LG (C) ..... Waites: ahah ate 8
2SC945L (P) (Q) (R).-.--. ee 75
2SC1175 (E) (F) -....-.-+.-- 3
2SC1211 (E) (F) ...-. 6.6666. 1
28C1222 (E) (F) .....-.----. 4
2SC1647 (S) (E) ............ 6
2SC1683 (P) (Q) ............ 1 gses
2SD360 (D) (E) .........-.. 1
2SD361 (D) (E) (D1) ........ 2
2SD401 (K) (L) .....-...6.- 1
2SD571 (K) (L) (M)...... bad
FET 2SK30A (D) (GR) ....-...--5 10
2SK68A (L) (M) ...........- 2
IC wPCLO23H..............-..- 2
wPC10O24H.... 0... eee 4
TATL22AP posit ata ee 8 2
DN835) 2 2. eee eee esis 1
DIODE ENB 4 Aire oi. eens ane Meter eee 8
18247330 ei et ee es 59
IS2473VE «5 eee-o ed sere eae 88
LOD 2S te ee aes pa 4
MODS i. 2 eee AAS Se os 1
LODS tes canted seat ePned ". 6
7 WZ085 ....... 02 cee eee 2
WZ 240» iio cia Decale pirat ae 2
POWER REQUIREMENTS
CSA, UL and LA Models: 120V, 60 Hz only
CEE Models: 220V, 50 Hz only
Other Models: 100V to 240V, 50/60 Hz, (switchable)
DIMENSIONS
WEIGHT .
440(W) x 255(H) x 225(D) mm
(17.3 x 10.0 x 8.9")
13.5 kg (28.5 Ibs)
NOTES: 1. For improvement purposes, specifications and design are subject to change without notice.
2. Noise reduction circuit made under license from Dolby Laboratories Inc.
The word ‘DOLBY’ and the Double-D symbol are trademarks of Dolby Laboratories Inc.

ll. DISMANTLING OF UNIT
In case of trouble, etc. necessitating disassembly, please disassemble in the order shown in photographs. Reassemble
in reverse order. ie
‘ Co
SCREWS
SCREWS
SCREWS
10 PANEL -
He SCREWS
CONNECTORS
SCREWS & CONTROL KNOBS
otis 5.

at
SCREWS
SCREWS
AMP BLOCK
MECHA BLOCK
“-

lll.
PRINCIPAL
PARTS
LOCATION
TAPE SELECTOR REC CALIBRATION DOLBY N.R
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PiTCH CONT CAL TONE DOLBY N.R IND MPX FILTER
FF-RWD SPEED
LIMITER
VU METER
DOOR
EVECT
PEAK METER
VU METER
TAPE COUNTER
HEAD BLOCK
METER SELECTOR
LINE REC LEVEL
MIC REC LEVEL
TOUCH
BUTTON
SWITCH
OUTPUT
MIC
JACK
REPEAT
MEMORY
SES.
MONITOR
Py
POWER
SUPPLY
&
OSC
DOOR
SWITCH
PC
:
PRE
AMP
P.C
BOARD
CA-5205
RC
BOARD
CI-5030
BOARD
Cl-5026
CAPACITOR C4 330/160
POWER TRANSFORMER
POWER
HEADPHONE JACK
Fig.1 Front View
DOOR OPEN MOTOR
RF -260-09400
CAPSTAN MOTOR SCM-700
SERVO PRC BOARD CI-2020
cit-1
f : VOLT SELECTOR
REMOTE CONTROL JACK
MONITOR SWITCH PRC
BOARD CI-5003 i
SYSCON
PC
BOARD
TOUCH
SWITCH
RC
BOARD
CB
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5004
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CAPACITOR C3 6/150
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Fig.2 Rear View

IV. CIRCUIT OPERATING PRINCIPLES
1. SYSTEM CONTROL OPERATION
|, |NOSE FILTER
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WIND SPEED CONTROL,
BACK TENSION CASSETTE PACK OETECTION
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STOP DETECTION RC
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BOARD Cl:
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BOARD CB-5004
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SCHEMATIC-4 FF MODE
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