Revox B225 Service Manual
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REI/QX
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B225
IiILI„OF_CgNTEyTS page
1. GENERAL
1-1 Index of CO olayer controls 1/i
1*1* 1 General controls 1/1
1*1*2 Special controls 1/2
1*1*3 Rear panel connectors 1/3
2. t REMOVAL OF ASSEHBLIES
2.1 Removing the top cover 2/1
2*2 Removing tne side panels 2/1
2.3 Removing the individual circuit boards 2/1
2*4 Removing the player mechanism 2/1
2®5 Removing the display 2/2
2*6 Removing the po^er
2*7 Removing the drawer motor 2/1
2*8 Removing tne operating panel 2/3
Z«9 Removing the guide rods 2/3
t r
ansf or mator 2/2
3* CIRCUIT DESCRIPTIONS
3.1 SERVO 1 PC3 1.759.310 3/1
3.1®1 Stabilization of the supply voltages 3/1
3*1*2
Orawer position detector 3/1
3*1.3 Focus control loop 3/2
3*1*4
Oisc motor control loop 3/2
3.2 Microprocessor PC3 . 1.769.320 3/3
3.2*1 Microprocessor system 3/3
3^2*2
Drawer motor control 3/4
3*3 SERVO- 2 PCP 1.769*330 3/4
3.3^1 Radial control 3/4
3*3.2
Radial control circuit 3/4
3*3*3
Automatic gain control- {AGC-} circuit 3/5
3«3r-4 Offset control circuit. 3/5
3.3.5 Track detecting circuit 3/6
3*4 Preamplifier and laser PCB 1*769*100*35 3/6
3.4.1 Laser control 3/6
3*4^2
Focus and radial control signals 3/6
3«4*3 HF signal amplifier 3/6
3.5 Decoder PCh l-7o^.300 3/6
3*
t>
• 1 Digital signal processing
3»5«2 Digital sine-wave generator 3/7
3.
5. J
HFL and 0-J detector 3/7
3*o OAC TC3 1.769.23 3 3/7
3.t».l
digital filtering (oversampl ing) and 0/A conversion 3/7
3*6.2
Level adjustment and headphones amplifier 3/3
3/7
mmmm
*• TEST POINTSt ADJUSTMENTS OH E225
4 i Test points on 622^ 4/1
4«-l»l Test points on SERVO I PCB 1«?69*310 4/1
4.1.2 Test points on SERVO 2 PCB 1.769.330 4/3
4.1.3 Test points on microprocessor PCB 1.769*320 4/4
4.1.4 Test points on decoder PCB 1.769.300 4/6
4.1.5 Test points on 0AC- PCB 1.769.260 4/8
4®2 Adjustments on CO player B225 4/9
4.2.1 Aids 4/9
4.2.2 Aligning the player mechanism? general 4/9
4*2®3
4.2.4 Adjusting the balance 4/9
4«Z*5 Adjusting the focus gain 4/10
4*2*6
4*»2#7
4.3 Measuring the audi.o data 4/11
4*3.1
A i 4s
4*3#2
4.3.3 Output level 4/11
4.3*4
4.3.5 Cross talk 4/12
4.3.6 Signal-to-noise ratio* linear 4/12
4.3.7 Signal-to-noise ratio? weighted - ' 4/12
4.3.3 Phase linearity 4/12
4.4 Listening test with reference CO 4/12
eel/ox
Adjusting the laser current 4/9
Checking the -tingle alignment 4/10
Adjusting the DC component of the focus signal 4/11
Harmonic distortion 4/11
Frequency response 4/11
B225
4/i1
5* DIAGRAMS
6. SPARE PARTS
7*
TECHNICAL APPENDIX
7.1 Technical data 7/1
7«Z
Dimensions 7/2"
R^/ax
B225
1.
1.1
1.1.1
1 Ij POWER *
[
2 j
LOAD
[
3 J
STOP *
[
4 J
PLAY/NEXT
H5"f REPEAT
[6j (CD drive)
[7j (Display)
[8j (keys 0-9)
GENERAL
Index of CD player controls
General controls
Key for switching the CD player ON and
OFF.
However, certain assemblies (such
as the IR receiver) remain always switched"
on (in so-called standby
The drawer with the player mechanism
[6j opens or closes when this key is
pressed.
Interrupts the player function. The
optical laser head is retracted to the
starting position and the program is
cancelled if the CD player was in program
mode.
The position in which the laser
pickup was operating before STOP was
pressed cannot be reproduced. If this
is desired, please refer to tJL (PAUSE)
key.
Play key with the following functions;
If pressed after LOAD [2j, the CD starts
to rotate, the content list is read, and
the disc is played starting at the first
selection
(TRACK) is accessed when this key is
pressed again.
If pressed after PROGRAM MODE [26 J has
been selected: play program mode is
activated.
The selection currf.r^ly being played
is repeated immediately when this key
is pressed. If the CD player is in STOP
mode,
disc will be played. If the CD player is
in program mode, the current program step
will be repeated.
Drawer module with CD player mechanism
and liquid-crystal display. The drawer
can be opened or closed with LOAD [2].
Multifunction LC display 'which provides
information on all operating modes of
the CD player and the content of the
loaded compact disc.
Digit keys for direct addressing of
a selection (TRACK) in conjunction with
PLAY/NEXT [4j, or for programming.
(TRACK).
the first selection of the compact
The next selection
mode).
The CD player can be switched on by pressing any of
the controls [ Ij through [8j of the upper row (except
REPEAT [5j and the digit key 0). The CD player starts
in the selected operating mode.
mruim
REVOX
B225
1.1.2
The controls
roughly divided into
for supplementary player functions,
controls.
A Controls
[9] PHONES
[10] VOLUME
[11j VOLUME
[12]
CAL
13] AUTOSTOP
[ 14j
Key •
[ 15 J
VA
[16]
« key
[17] DISPLAY
Special controls
in the
+
-
TONE
*
(pause ) *
lower front-panel section
two
for
Headphones jaGk socket
200
Increases
and
Decreases
and
This calibration button connects
1000
outputs
of a connected tape deck
accurately adjusted.
CAL TONE corresponds
output level. This maximum level
is system-dependent
be exceeded even
pulses.
Interrupts
at
or program step.
is automatically positioned
the beginning
The next selection
immediately when PAUSE
pressed. Upon conclusion
selection,
again
Repositions
location toward
Interrupts
at
Repositions
location toward
Switches over
The time elapsed since
of
in normal PLAY mode.
play time from
current selection
by pressing this
function groups: controls
supplementary player functions
to 600
the
the
Hz
the end of the
any
the
ohms.
the
level
level
calibration tone
so
to
time.
current selection
headphones level
of the
the
headphones level
of the
that
the
of the
the CD
PAUSE mode.
the
the
the
the
can be
and
programming
for
headphones
VARIABLE OUTPUT.
VARIABLE OUTPUT
the
by
playing sequence
current selection
The
is
player switches
pickup from
the end.
playing sequence
pickup from
the
display mode.
the
start
can be
key.
to the
recording level
can be
The 1000 Hz
to the
and
short peak
laser pickup
next selection.
started
start.
The
maximum
will
not
at
TA [15] is
of
this
any
any
the
start
is
displayed
total
to the
displayed
a
These functions
PROGRAMMING keys
18] LOOP
19]
[20]
[21]
[ 22] STORE
[ 23] MARK
[24] TRACK/TIME
+
-
IR
*
SENSOR
can
also
be
programmed.
Command key for repeating the CD
or the proqr^4«until STOP [3j is
pressed.
Forward "paging" in program mode.
Particularly useful for modifying
an existing program.
Same function as [19] but backward
paging.
Infrared receiver window
Memory load key to be pressed after
each program step entry. The next
program step is subsequently
displayed so that the corresponding
entries can be made.
Allows a start and a stop mark
to be set in programming mode while
a selection is being played. Any
CD location can thus be programmed.
Switches the display in programming
mode from selection (track) input
to time input (minutes and
seconds).
mWU\n)MPd
R^OX
B225
[25j CURSOR
[26 J
PROGRAM
Any position on the display can
be edited by approaching it with the
cursor.
TIME mode, the cursor must be
advanced with this key in order to
enter the seconds after the minutes.
Sets the program entry mode. If
PLAY/NEXT [4J is pressed after
the program entries have been
completed, the CD player starts in
PROGRAM mode,
If the CD player is to be started
in normal mode after the program
entries have been completed, press
the PROGRAM key
PLAY/NEXT [4].
NOTE; if the display is in
[ 26 J
again before
1.1.3 Rear-panel connectors
[30] AUDIO OUTPUT FIXED. Output for connecting
[31] AUDIO OUTPUT VARIABLE. Active speakers or
[32] AC POWER. Power inlet (the setting of the
..[33J
• "
an amplifier on which the input can be matched
to the level of the CD player (the REVOX B251
amplifier is ideally matched at the
an output stagef etc. can be connected directly
to this output. The volume can be adjusted
with VOLUME + and - on the front panel of
the CD player.
line voltage selector can be checked adjacent
to it ) .
REMOTE. This connector can be used for: a)
disabling the IR receiver and b) connecting
a cable-type remote control device.
factory).
B^OX
B225
2 . REMOVAL OF ASSEMBLIES
Important:
Disconnect the CD player from the AC supply before
removing any parts of the housing.. For certain work
it is necessary to open or close the drawer module.
This can be done manually without damaging the unit.
2.1 Removing the top cover
- Unfasten five screws [Aj on the rear of the CD player.
- Withdraw cover toward the rear.
2.2 Removing the side panels
- Unfasten two screws on each side panel in order to
remove them.
2
. 3
Removing the individual circuit boards
SECTION 2/1
The circuit boards are accessible when the top cover
is removed (Section 2.1).
The circuit boards 1.769.280 (DAC PCB), 1.769.300
(DECODER PCB), and 1.769.330 (SERVO 2 PCB) can be pulled
out of the interconnection board after the fixing screws
[ B] have been unfastened.
Four connectors must be detached before the PCB 1.769.320
(MICROPROCESSOR) is removed. Then unfasten screw [Bj
and withdraw the PCB from the housing toward the rear.
The SERVO 1 PCB 1.769.310 is connected to the chassis
via the cooling plate of the voltage regulators. First
detach all connectors leading to this PCB. Push the
drawer out completely in order to gain access to the
three fixing screws. The three screws [C] can
subsequently be unfastened and the PCB withdrawn toward
the rear
2
. 4
.
Removing the player mechanism.
- Remove top cover (Section 2.1)
- Push drawer out part of the way and set the CD player
upside down.
- Now pull the drawer out to the point where the screws
[ Dj ^become accessible.
- Unfasten screw [Dj and set the CD player again in its
- . ~ normal operating position on the
fc--^ch
(NOTE; hold the
player mechanism with your hand to prevent it from
falling out of the
drawer).
- Pull drawer out completely and carefully lift the CD
player.
'umrnm ¥%EMOK
Detach the six connectors (see Fig. 2.5).
The player mechanism can now be lifted out of the
drawer»
2.5 Removing the display
B225
SECTION 2/2
- Open the drawer and unfasten two screws [ Ej
on each
side.
- Unfasten cable clamp [F] and detach connector of
cable harness. The display can now be lifted out
by carefully sliding the cable harness out below
the player mechanism.
2 •6
Removing the power transformer
- Remove top cover (see Section 2.1).
•
- JJniiasten four screws [Gj from the bottom.
- Detach the connectors of the power transformer to
the SERVO 1 PCB 1.769.310, remove power inlet by
unfastening the two screws and unfasten screw [Hj
(black cable, soldering tag).
- The transformer can now be removed.
2.7 Removing the drawer motor
- Remove top cover (see Section 2.1).
- Remove power transformer (see Section 2.6).
- Unfasten three screws [Hj from the top, unhook spring
[I],
detach connectors leading from the motor to
the microprocessor PCB 1.769.320, and carefully lift
out the motor.
UJPEMKi KEl/OX
• .
B226
2.8 Removing the operating panel
- Remove top cover (Section 2.1) and side panels
(Section 2.2).
- Unfasten four screws [Kj each on the top and the
bottom of the operating panel.
Carefully withdraw operating panel' from the chassis
and detach the connectors.
2 -9
Removing the guide rods
- Remove top cover (see Section 2.1).
- Unfasten the inner retaining ring [Lj; the rod can
now be pulled out of the unit from the rear.
Note:
Do not lose the small O-ring that cushions the
drawer stop-
2.10 Reassembly
The CD player is reassembled by following the dismantling
steps in the reverse order. It is absolutely essential to
secure the cable harness in the drawer with a clip as
illustrated in Fig. 2.7.
R^OX
3. CIRCUIT DESCRIPTIONS
B225
SECTION 3/1
3.1 SERVO 1 PCB
The following circuits are implemented on the SERVO 1
PCB;
- Stabilization of the supply voltages
- Drawer position detector
- Focus control loop
- Disc motor control loop
3.1.1 Stabilization of the supply voltages
All supply voltages are stabilized by voltage controllers
(IC 4 to IC 9,
The +5V supply (+5 V STBY) is always available. It
supplies the microprocessor system and the IR receiver
even when the CD player is switched off
The remaining supply voltages are switched on or off
by the microprocessor with the PS-OFF signal. When
the CD player is switched off, PS-OFF becomes "H" (+5 V)
and transistors Q9 and Q10 become conductive
(staturated),
to drop to a residual voltage of 1.3 V. The -7 V supply
is switched off through the circuit R38,
the -12 V supply via R52, R54, and Qll; and the -17 V
supply via R51,
supply voltages from becoming negative. The voltage
is doubled through diodes D15, D16, D17 and capacitors
C29,
C30# and taken to the voltage controller IC9 for
the -17 V supply. D18 protects the controller from
an excessive direct-axis component of the voltage.
1.769.310
LM317/LM337).
(standby).
causing the +5 V and +12 V supply voltages
R39? and Q8;
R53f and Q12. This prevents the positive
3.1.2 Drawer position detector
The two light barriers DLQ1 and DLQ2 (on PCB
1.769.310)
check whether the drawer is open or closed. The
corresponding signals indicate the following conditions:
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