Akai CD 79 Service Manual

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Akai CD 79 Service Manual

Extracted text from Akai CD 79 Service Manual (Ocr-read)

Page 1




Mr mum on







Pickup ............................ 3 beam Laser pick up
Pick-up system .......... ...Linear tracking

Sampling frequency.. 44.1 kHz
Digital filter ................ ...20 bit, 8 times over sampling
D/A converter .................. Sign magnitude

L, Ft independent
Error correction system ..Cross lnterleave Reed
Number of channels ........ 2 channels stereo
Frequency response ...... 2 Hz to 20 kHz :05 dB
Dynamic range

CD-69 ................ 100 dB
CD-79 ................ 101 dB
CD-69 .......................... 114 dB
CD-79 .......................... 116 dB
Total harmonic distortion
CD~69 .......................... 00022 % or less
(DD-79 ....... ...0.0018 % or less

Wow & flutter (Less than measurable limits

Output level/impedance
Analog (Fixed) ..
Analog (Variable) .
Digital (Coaxial) ........ 0.5 Vp-p/75 ohms
Digital (Optical)..

Power requirementst

25 mW/82 ohms

except UK
240 V, 50 Hz for U K
Dimensions .................... 425 (W) x 120 (H)x 348 (D)mm
00.69 ..5.7 kg

CD-79 .. .. 9.3 kg

,. -22 st,wave lergth 660 nm

.. 220 V~230 V, 50 Hz for Europe

Standard accessories
Connection cord ..........
Remote control unit .
Batteries for remote control unit ...... 2
Operators manual .......................... 1

>l< For improvement purposes, specifications and design are subject to change without notice.

Page 2

r... .



1. Parts indentitied by the .1. (*) symbol are critical lor
salety. Replace them only with the pans number speci-

. In addition to salety. other parts and assemblies are

specilled tor oonlormarice Wllh suoh regulations as

those applying to spurious radiation,

These must also be replaced only with the specilled ra-


Examples: FlF converters, tuner units, antenna selec-
tor switches. RF cables. noise blocking ca-
pacitors. noise blocking litters. etc.

Use specified internal wiring, Note especmlly:

t)Wires oovered with PVC tubing

2) Double insulated wires

3) High voltage leads

4 Use specified insulating materials tor hazardous live

parts. Note especially

1) Insulation Tape

2) PVC tubing

3) Spacers ilnsulatirig barriers)

4) Insulation sheets lot transistors

5) Plastic suews tor tlxlng microsztol (especially in

.Wlien replaong AC primary sioe components (trans-

iormers, power oords. noise blocking capacitors. etc).
wrap the ends at the wires securely about the termi-

nals oetore soldering





. Make sure that wires do riot contact heat producing
pans (heatsmks. oxide metal Illm resistors. lusible re-
slstors. eta).

.cheok that replaoed wires do not contact sharp edged
or pointed parts.

8 Also check areas surrounding repaired locations.

Make sure that totalng obiects (suews. solder drop~

lets. etc.) do not remain inside the set.



- ssnwc: MANUAL


After servicing. make measurements at leakage-current
or resistance in order to determine that exposed pans are
aweptably insulated trom the supply circuit,

The Ieakage~current measurement should be done be-
tween aooessiole metal pans (such as chassis. ground
terminal. microphone tacks. signal input] output connec-
tors. etc.) and the earth ground through a resistor or 1500
ohms paralleled with a o,i5 pF capacitor. under the

units normal working conditions, The leakage-current
should be less than 0.5 mA rms AC.

The re5lstanbe measurement should be done between
accessible exposed metalparts and power oord plug prongs
with the power swttcn (it included) 'ON". The reelstanoe
should be more than 2 2 Mohms,


Used batterles with the lSO symbol lot recy-

ding as well as small accumulators (recharge~%
able batteries). mini-batteries (cells) and starter

batteries should not be thrown into the garbage can.
Please leave them at an appropriate depot, All other

household batteries can be thrown but with the household


This product oontains a low power laser device.

.To ensure continued safely. do not remove any oovers
lor attempt to gain access to the inside oi the product,
'Fleler any servicing to ooalnied personnel.

Use actual size stickers

555 t usen noou
Luolwi I user: units

st ussii nan

willows. me am a. ..
Safe-511??? it?! :"" ""°'
VANO m... .




When repairing or adjusmg the unit. please note the lol-

Iowing points.

i. Do not put excessive pressure on the mechanical part
(operation part). including the pick-up block. as ex-
tremely high mechanical precision is required in these

2. When the base is removed tor repair or adjustment.
make sure that there are no metal oblects in the nar-
row gap between the F.C.buard or the mecha parts
and the base.

3 The Micro-Computer and the on signal processing le
man be damaged by static electricity or leakage from a
soldering iron during repairing
While soldering. please take the precautions against
leakage as in the illustration.

, mo

4, Do not loosen arty screws in the pick-up blade
When handing the pick-up bloat. please rater to the
points to NOTE when replaong the plot-up block.

5. Keep salety for hazardous invisible Laser Radiation.
DO NOT watch the Laser Beam (Obiective lens) di-

6. Models lor the some countries. laser warning labels
are attixod on the unit and inside 01 the unit, as shown

Read it welully tor your safety. when repairing or ad-
justing the unit.

Primary destination at unit: are indicated with the loltow-
inn alphabet.


Universal Area
Custom version

Page 26



Pin No. Symbol no Description Pin No. Symbol IIO Description . .

1 TE I Tracking error Input terminal. 43 CE I DEFECT bottom hold capacitor connecting terminal.

a TDFOT I Time constant a. wile! eonnating terminal at time at aetect. 44 CF I Terminal tor connection or MIRR hold capacflnr-

3 ATSC I Window corrparator input terminal tor ATSC detection. (Non inverted inPUl B'mjlal 0' MIR comratori)

4 F20 I Terminal lor locus zero comparator input. 45 RFI I Input terminal ol RF summing amp output which is supplied through a

5 FE I Focus error input terminal capacitori

l5 FDFCT I Time constant ca acitor oennetlng terminal at time at detect. as RFO 0 RF summing arrlp output terminal (Check point lor eye pattern.)

7 vs I Center voltage Input terminal 47 DVEE - '5 V

8 Feb I In case, reducing hlgh range gain of locus servo amp, connect a 45 TZC I Input terminal ol tracking zero cross comparator.
capacitor beMeen the F53 terminal and this terminal.

9 F53 | Switches high range gain at locus servo amp according to whether
F8: is on or oll.

10 FLB I External terminal for controlling limo costant lor boosting locus servo OXA157IS (RF AMP)
low mega 93m Pin No. Symbol No Description

It FEO 0 Focus drlve outpuL 1 NC _ No connection

12 FE - I Inverted input terminal at locus amp, 2 LD 0 APO amp output terminal

13 SRCH I External terminal lor controlling time constant tor producing locus 3 PD l APC amp input terminal.
59 3 '°" . 4 PDI l FIF I-V amp inverted input terminal (tor photo diode A+C of pick up)

14 TGU I External terminal lor controlling time constant tor switching ol tracking 5 PD2 | RF l-V amp inverted input terminal (lor photo diode E+D 01 pick up)
amp high range gain. 6 VEE _ _5 V

15 T6 2 I External terminal lor controlling time constant tor switching ol tracking 7 PIN I RF l-V amp inverted input terminal (lor photo diode F at pick up)
amp 9" ""5" 9" a E-IN I RF t-V arrtp inverted input terminal (tor photo diode E at pick up)

"5 0° *5 V e VR 0 tvcc + vaelrz no voltage output terminal.

7 0 ° am"g °"° 9 . to vc l Center voltage input terminal of vc. (Connect to GND when :sv

18 TA ' I Inverted input tenninai ol tracking omp. power supply is used. connect to VR when +5V power supply is used.

19 SL 4, I Input terminal lor sled amp. 1 NC _ No connection

20 SLO O Sled drive output. 12 NC _ No connection

2 5L - I "Wm. input °""'"fl_ tor 5' amp. . _ 13 E0 0 Output terminal tor I-V amp E monitor.

22 FSET I Terminal lol' peak setting Ior locus tracking phase compensation. 14 El _ Terminal lor gain control 0' W amp E.

23 ISET I Terminal 01 source current which dealdes level at locus search. 15 TE 0 Tracking error amp output terminal (E-F signal is output.)
track-lump 9d,? CK , . ~ 16 FE-BLAS l Terminal lor bias adlustmant ol locus error amp inverted side.

24 SSTOP l Termtnal ol llmlt swflch ON/OFF detection tor disk innermost track 17 FE 0 Focus error amp output terminal.
mm"- ta FIFO 0 RF amp output terminal.

25 AVEE ' '5 V . ' Inverted side input terminal at RF amp.

26 DIFlC I used 8' "m9 ol "51? . t9 RFI | (The gain ol RF arrp is decided by the value ol the resistor connected
(7 ms P" 9" afsf '5 59") between this terminal and the FIFO terminal)

27 LOCK 5'9 U" P'°V°"°" cm" was 3 1 20 LD«0N | Terminal tor ON/OFF switching ol APO amp, icnp : ON, Voc : OFF)
(47k ohrm pull up resistor is Inserted.) 21 V00 _ 5 V

28 CLK I Serial data transmission clock input lrom CPU. (No pull up resistor) 22 NC _ No connection

29 XLT I Latch input tram CPU. (No pull up resistor)

30 DATA I Serial data input trom CPUi (No pull up reelstor)

31 XHST I Reset input terminal. (Reset at "L.)

32 SENS o Outputs FZC, AS, TZC. SSTOP etc. according to command lrom

33 C OUT 0 Output Ior track number count signal.

34 D GND - GND

35 MIRR O MIRR comparator output terminal.

36 DFCT O DEFECT comparator output terminal,

37 ASV | Auto asymmetry control input terminal

38 EFM O EFM comparator output terminal.

39 FOK 0 Focus 0K comparator output terminal

40 cor r DEFECT bottom hold output terminal.

41 002 0 Input termlnal cl DEFECT bottom hold output which is supplied
through a capacitor.

42 DVCC - +5 V