Pioneer CT-F615 User manual

waste Pll ease
saws e382200 less
yysssessee
CASSETTE TAPE DECK |
T-FG61
YPIONEER’

MODEL CT-F615 COMES IN ONE VERSION DISTINGUISHED AS FOLLOWS.
Voltage Remarks
120V only U.S.A. model
CONTENTS }
1. SPECIFICATIONS ....... testa dese’ Dede 3 10. SCHEMATIC DIAGRAMS, P.C. BOARD
2. FRONT PANEL FACILITIES ............. 4 PATTERNS CUD EAR sot,
3, DISASSEMBLY ..........0..0es ees ee ee 6 HOSL., MUMpCoM ANOS «sti atte ate tac hcio 24
4. PARTS LOCATION ................22 2. 7 10.2 Schematic Diagram .......... Ae Seah 25
5. LEVEL DIAGRAM ................... 9 10.3. P.C. Board Connection Diagram ...... 28
6. BLOCK DIAGRAM ................... 1 10.4 Connection Diagram ...........-.. 31
7. CIRCUIT DESCRIPTIONS 10.5 F.L.Meter Assembly .............. 32
71 Slafial Pathes+c8) <4 yuanien cca sadee 13 10.6 Mother Assembly .............04- 33
7.2 Recording and Playback Circuit. ...... 13 EO ,7-* sich Smrttch PAsseMINY arse src oth 37
73 Control Circuit... 2... ce cece eee 15 TOE NIUE ROMY ca oes Sra eas 37
7.4 MutingCircuit..........0. 00000. 16 Ore er maa ae reac aenee p ear aes a?
75 Piiniind CHaphes cose hosed ee atescta lod. hs 17 10.10 Timer Switch Assembly ............ 37
8. MECHANICAL ADJUSTMENTS 11. EXPLODED VIEWS AND PARTS LIST
8.1 Pinch Roller Pressure Adjustement..... 19 WT aL PEATE ON COMPODEUE ci 2.aeSpto en ney ve
8.2 AubeliBase Toegue‘Adjustients ao2%0.2 19 11.2 Interior Component .............. 41
g's itaps Sheed Adiustnentes-is eked teae 49 12.< PACKING | 2 assed ae eeu be desde eee ge ee o's 44
8.4 Play Solenoid Adjustment .......... 19
8.5 F.F Solenoid Adjustment ep hb aie. & Ane ie ms 20
8.6 REW Solenoid Adjustment .......... 20
8.7 REC Solenoid Adjustment .......... 20
9. ELECTRICAL ADJUSTMENTS
9.1 Head Azimuth Adjustment........<. 21
9.2 Playback Equalizer Check .......... 21
9.3 Playback Level Adjustment ......... 22
9.4 F.L. Meter Adjustment ............ 22
9.5 Recording Rough Adjustment ........ 22
9.6 Erasure Current Adjustment ......... 22
9.7 Bias Trap Adjustment ............. 22
98 Recording Bias Rough Adjustment... .. 22
9.9 Recording/Playback Frequency
Response Check and Adjustment ...... 22
9.10 Recording Level Adjustment......... 23
NOTE;
@
This
service
manual
is
applicable
to
the
CT-F615/KU
type
which
serial
numbers
from
ZL3600001
through
ZL3600100.
e As an improvement, the mother assembly was modified of which serial numbers are after ZL3600101. For
detailed, refer to the additional service manual on page 45.

1. SPECIFICATIONS
SYSTEMS os gov Ss eS) BOs a Compact cassette, 2-channel stereo
IMOLOt eo ia, gt el ace da et etets ee Us, cane te See ee DC servo motor x 1
Heads ............ “Sendust’’ recording/playback head x 1
: F Erasing head x 1
Fast Winding Time ............ Approximately 100 seconds
(C-60 tape)
Wowand
Flutter...
2.0.2.0...
No
more
than
0.06%
(WRMS)
Frequency
Response
Standard, LH tapes... .............. 20 to 15,000Hz
(25 to 14,000Hz + 3dB)
Ferrichrome tape... 2... 2.2.0.0 0-.0004 20 to 17,000Hz
(25 to 16,000Hz + 3dB)
Chromium dioxide tape .. 2. ....2..20.0. 20 to 17,000Hz
(25 to 16,000Hz + 3dB)
Metal tape............00000eeeee 20 to 18,000Hz
(25 to 17,000Hz + 3dB)
. Dolby NR OFF; More than 58dB
Dolby NR ON; More than 68dB
(over 5kHz)
Harmonic Distortion... ......... No more than 1.3% (QdB)
Input (Sensitivity/Maximum allowable input/Impedance)
MIC (L, R); 0.3mV/100mV/10 kitohms, 6mm diam, jack
(Reference MIC impedance; 250 ohms to 10 kilohms)
LINE x 2; 50mV/25V/75 kilohms Pin jack
Output (Reference level/Load impedance)
LINE x 2; 450mV/50 kilohms Pin jack
HEADPHONES x 1; 73mV/8 ohms, 6mm diam. jack
Semiconductors
Signal-to-Noise Ratio
Amplifier Section ..............00- Transistor x 55
Diodes x 45 (Zener x 3, LED x 3), ICs x 5
Motor control Section. ......... Transistor x 2, Diode x 1
Subfunctions .
e@ Air damp eject function
e@ Fluorescent display level meter (—20 to +8dB)
e 4position tape selector (STD/Fe-Cr/CrO2/METAL)
@ IC logic control
CT-F615
e Dolby NR system (ON/OFF)
e@ Standby mechanism with unattended recording
e REC muting function
e@ Full automatic stop mechanism
Power Requirements. ................. AC120V, 60Hz
Power Consumption .........0..... 0000 aes 31 watts
Dimensions ............ 420(W) x 98(H) x 328(D})mm Max.
16-9/16 x 3-7/8 x 12-15/16in.
Weights o aares dog ete ack be ere hohe algae An is 6kg (13 tb 40z)
Furnished Parts... .. Stereo connecting cords with pin plugs x 2
Head cleaning swabs x 3
Operating instructions x 1
Note:
Specifications and the design subject to possible modification
without notice due to improvements.
NOTES:
1. Reference Recording Level: Meter OdB indicating level (160
nwb/m magnetic level = Philips cassette reference level)
2. Reference Signal: 333Hz
3. Wow & Flutter: @ JIS [3kHz, with acoustic compensation
(weighted), rms value]
4. Frequency Response: @ Measured at —20dB level, DOLBY NR
OFF, level deviation is +6dB without indication.
5. Signal to Noise Ratio: @ Measured at the third harmonic dis-
tortion 3% level, weighted.
6. Sensitivity: Input level (mV) required for reference recording
level with input (REC) controls set to maximum.
7. Maximum Allowable Input: While decreasing settings of input
(REC) level controls and increasing level at input jacks, this is
the maximum input level (mV) at the point where recording
amplifier output waveform becomes clipped.
8. Reference Output Level: Playback output level when meter
indicates OdB. .
* Manufactured under license from Dotby Laboratories,
*Dolby and 90 are trademarks of Dolby Laboratories.

2.
FRONT
PANEL
FACILITIES
@
POWER
SWITCH
Power
is
supplied
to
the
deck
when
this
switch
is
set
to
ON,
and
the
level
meter
lights
up.
To
turn
OFF
the
power,
set
it
to
bottom
position.
@
TIMER
START
SWITCH
This
is
used
when
the
timer
is
employed
along
with
the
deck
for
unattended
recording
and
wake
up
playback.
REC:
Set
to
this
position
to
set
the
deck
automatically
to
the
recording
mode
at
the
time
preset
on
the
timer
and
to
start
the
recording
of
programs
unattended,
for
in-
stance.
OFF:
Set
to
this
position
for
normal
tape
playback
and
record-
ing.
PLAY:
Set
to
this
position
to
set
the
deck
automatically
to
the
playback
mode
at
the
time
preset
on
the
timer
and
to
start
the
playback.
The
tape
playback
function
can
be
used
to
wake
up
in
the
morning
instead
of
an
alarm
clock.
@
CASSETTE
HOLDER/EJECT
BUTTON
The
cassette
tapes
are
loaded
into
this
holder.
It
jumps
out
when
the
EJECT
button
is
depressed.
To
close
the
holder,
push
the
top
back
until
it
locks.
@
REMAINING
TAPE
MARKER
if
this
marker
is
visible,
it
means
that
there
is
enough
tape
remain-
ing
for
several
minutes
of
recording
or
playback.
@
COUNTER
RESET
BUTTON/TAPE
COUNTER
Depress
this
button
to
reset
the
tape
counter
display
to
“000.”
Tape
counter
indicates
the
position
of
the
tape
run.
@®
LEVEL
METERS
These
indicate
the
input
level
during
recording
and
the
output
level
during
playback.
@
INPUT
(RECORDING
LEVEL)
CONTROLS
Use
these
to
adjust
the
level
of
the
input
signals
from
the
MIC
jacks
or
rear
panel
LINE-INPUT.
Turning
these
controls
to
the
right
increases
the
level.
The
controls
are
coupled
to
the
left
and
right
channels,
but
you
can
also
use
them
to
adjust
the
right
channel
(back)
and
the
left
channel
(front)
independently.
HEADPHONE
JACK
This
is
the
output
jack
for
stereo
headphones.
Plug
your
head-
phones
into
this
jack
when
you
want
to
monitor
the
quality
of
a
recording
or
when
you
want
to
listen
to
a
tape
privately.
NOTES:
@
Use
low-impedance
headphones.
If
you
use
a
high-impedance
model,
you
will
not
be
able
to
obtain
sufficient
volume,
©
You
will
damage
the
microphone
if
you
plug
it
into
this
jack
by
mistake.
@ MIC JACKS
These
are
the
input
jacks
for
microphone
recording.
Plug
the
left
channel
microphone
into
the
L
jack
and
the
right
channel
micro-
phone
into
the
R
jack.
REC
MUTE
SWITCH
While
this
switch
is
depressed
(ON)
during
recording
(switch
is
kept
depressed),
blanks
can
be
recorded
on
the
tape
since
the
in-
put
signals
are
not
recorded.
f

@ DOLBY NR SWITCH
Set
this
switch
to
ON
for
recording
with
the
built-in
Dolby
noise
reduction
system
and
for
the
Playback
of
tapes
which
have
been
recorded
using
the
Dolby
NR
system.
@2 TAPE SELECTOR
This
selector
allows
the
bias
and
equalizer
characteristics
to
be
selected
during
recording
and
the
equalizer
characteristics
during
playback
in.
line
with
the
type
of
tape
you
are
using.
STD
position:
For
using
standard
or
LH
tapes
Fe-Cr
position:
For
using
ferrichrome
tapes
HIGH
position:
Set
to
this
Position
when
using
chrome
or
metal
tapes
and
then
set
the
right-hand
switch
to
CrO2
or
METAL.
CrO.;
For
using
chrome
tapes
METAL;
For
using
metal
tapes
(3)
OPERATING
SWITCHES
4
(REW):
Depress
this
switch
to
rewind
the
tape
at
high
Speed.
(The
tape
will
travel
from
right
to
left.)
bP
(FF):
Depress
this
switch
to
send
the
tape
forward
at
high
speed.
(The
tape
will
travel
from
left
to
right.)
m
(Stop):
Depress
this
switch
ta
stop
the
tape
run
and
to
release
the
operating
switches,
>
(Play):
Depress
this
switch
when
playing
back
a
tape.
(The
tape
will
travel
from
left
to
right.)
REC:
Depress
this
switch
together
with
the
»
(Play)
switch
for
recording.
:
This
switch
will
not
work
when
a
Cassette
is
not
loaded
or
when
the
erasure
prevention
tabs
of
a
loaded
cassette
have
been
broken
off,
PAUSE:
Depress
this
switch
to
stop
the
tape
temporarily
during
recording
or
playback.
Depress
>
(Play)
switch
to
allow
the
tape
to
continue
to
travel.
NOTE:
@
The
operating
switches
will
not
return
to
their
original
Posi-
tions
even
when
the
power
is
switched
OFF.
CT-F615

3.
DISASSEMBLY
_
Mechanical
Ass’y
1. Disconnect the sensing belt coupling the take-up
BONNET ree] base to the runner.
Remove
screws
@
.
2.
Remove
screws
@.
Base Plate
Remove screws @.
Front Panel
Remove screws @ .
Bonnet
Fig. 1-1 Disassembly

CT-F615
the importance of the safety factor of the part. There-
:
fore,
when
replacing,
be
sure
to
use
parts
of
identical
Front Panel View designation.
4 PARTS LO CATION e The (\ mark found on some component parts indicates
Front panel sub assembly
RXX-285
Knob B (INPUT)
Eject knob (EJECT)
:
RAA-319
RAC-126
Knob A (INPUT)
Stand-by
knob
RAA-318
(TIMER START}
RAC-127
Lever knob A (POWER)
RAC-124
Lever KnobA
(TAPE SECLECTOR, DOLBY NR,
REC MUTE)
Pocket
door
assembly
RAC-124
a Lever knob B (TAPE SELECT)
RAC-125
Control knob
RAC-126
Front View with Front Panel Removed
F,L, meter
FIP 19A 14YS
Counter
F.L. meter assembly
RAW-130
RWX-352
Variable resistor (INPUT)
Timer switch assembly RCV-080
RWS-082
A Power switch Headphones jack
RSA-039 RIKN-060
Erase head MIC jack
PPB-056 RKN-059
REC/PB head
RPB-070
Lever switch C (REC MUTE)
RSK-060
Function switch assembly
RWS-081
Lever switch W
; (DOLBY NR)
RSK-061
Lt ver switch B (TAPE SELECT)
RSK-059
Lever switch A (TAPE SELECT)
RSK-058

Top
View
with
Bonnet
Removed
yg)
Mother
assembly
/\Power
transformer
RTT-207
PNA
A
Solenoid
Slide
switch
(REC/
RXP-085
PLAYBACK)
RSH-049
VR
assembly
RWX-353
Sensor assembly
RWX-354
Rear Panel Removed
Bonnet
RNA462
ass
S|
SSG)
.
A\
Strain
relief
Baad
ee
ence
Sarr
ra
tee
REC-272
AA
Power
code
RDG-022
4P mount pin jack
(LINE)
RKB014

5. LEVEL DIAGRAM
Playback
P-B Head 5
Level (dBv)
20
fe)
-20
—31.7dBV
(26mv)
—40
-40dBV
(10mvV)
P.B. Amp.
Gain =41.8dB
—-60
-73.5dBV
(0.21mvV)
-80
|
|
|
|
|
|
|
|
|
|
|
|
|
|
I
|
|
|
|
|
|
|
5.6dBV
(1.9V)
Head
On re
p Amp.
ey
Gain=124
DOLBY NR ee
& in=9,
i
ey
Gain
6dB
-~7dBV
1
Y
(0.44V)
Headphones
LINE
OUTPUT ue
Flat
Amp.
cara
(72.4mV)
Gain = 274dB
NOTE:
OdBV = 1V
Frequency : 333Hz
LINE
OUTPUT
;
Recording
Level (dBv)
10
-20
LINE
INPUT
—10dBV
(0.31V)
MIC Input
—21.8dBV
(81.3mv)
—28.8dBV
(36.3mvV)
MIC Amp.
Gain : 31.2dBV
-—40dBV
(lOmv)
—3dBV
-12.6dBV Gain:964B
(0.23V)
-6.8dBV
(0.45v)
CT-F615
LINE
OUT PUT
5.6dBV
(1.9V)
Headphones Amp
Gain =12.44B
LINE OUTPUT
-7dBV
(0.44V)
REC Head
xc
Headphones
Headphone
\ Output
Flat
Amp
—22.8dBV
(17.8mv) (72.4mV)
Gain :27.4dB
-35.4dBV (17 mV)
-33.8dBV(20.4mv)
—33.2dBV(21.9mvV)
NOTE;
OdBV = 1V
Frequency : 333Hz
10

6. BLOCK
LINE
INPUT
REC/PB Head
osc
LINE
ee
CT-F615
DIAGRAM
S6-1:MIC/LINE
VR601: INPUT VR
Flat Amp
Biastrap
S1:REC/PLAYBACK
$2:D0LBY NR
Fe-Cr
O=—O—> 24V
S3-1
VR101 Hi
S3: TAPE SELECTOR
PB
S1-7
REC
Q109
Headphone Amp Meter Amp
Q111
ang
# S
ait2 WW
VR304
Q110
Qn4s
24v
Dolby NR
REC Amp
Q108
L102
[ at, |
ie
Sensing Circuit
Headphones
Erase Head
REC/PB Head
RCR
RCH
VR 302 VR301
OSC Circuit
—_— 24Vv
LCH
S3: TAPE SELECTOR
S4: TAPE SELECTOR
ey Peal
Photo
interrupter
11
Muting Circuit
pt
$14: EJECT
S4-2 OMETAL
OFF
S3: TAPE SELECTOR
S4: TAPE SELECTOR
MUTE
S5: REC
Q314
Q321
REC/PB Head
S7
$B
so
S11
S16:
: PLAY
: STOP
DAF
S10:
REW
: PAUSE
S12:
S13:
REC
ERASE
PREVENT
DETECTOR
TIMER
12V
SL2
©)
:
5V
rey
Sy
alee
Q309
osi5 Q317
4
Qx16
Q306
AC3V
Q318
SL3
1 $L1:Pinch salenoid
$L2:F.F. solenoid
s_3: REW solenoid
sia: REC solenoid
S15
$15: POWER
AC120V
60Hz
12
SV
sié
°
5v (PLAY)
HOLE
NO HOLE
$13
Q325
REC/PLAY

7. CIRCUIT DESCRIPTIONS
7.1 SIGNAL PATHS
For an outline of the overall circuitry, see the
block diagram on page 11.
Play Mode
The output signal from the playback head is
first equalized in the playback equalizer amplifier
(Q101, Q102) according to the type of tape being
employed, and then passed to the flat amplifier
(Q104, Q105) where it is amplified to a fixed level.
The output of this stage is then applied to the
LINE OUTPUT via the Dolby amplifier.
Recording Mode
The input signal from MIC is first amplified to
a fixed level by the MIC amplifier (Q101, Q102),
and then applied via the MIC position of the S6-1
MIC/LINE switch (MIC position switched in auto-
matically when microphone plugged into the
microphone jacks) to the INPUT volume control,
flat amplifier, and Dolby amplifier. Part of the
Dolby amplifier output is applied to the LINE
OUTPUT, while the other part is applied to the
recording amplifier via the REC LEVEL ADJ.
VR108 control. After the frequency response
has been equalized by the recording amplifier
equalizer circuit (according to the type of tape
being employed), the signal is applied to the
recording head.
The input signal from the LINE INPUT is
passed via S6-1 to the flat amplifier, MPX filter,
and Dolby amplifier.
7.2 RECORDING AND PLAYBACK CIRCUITS
MIC/Equalizer Amplifier (Q101, Q102)
Consisting of 2 NPN transistors, this 2-stage
direct-coupled NFB amplifier is used as the MIC
amplifier (flat frequency response) during record-
ing mode by switching out the NFB circuit. Dur-
ing playback mode, the NFB circuit is used as a
time constant circuit for use as the playback
equalizer amplifier.
Flat Amplifier (0104, 0105)
The flat amplifier is also a 2-stage direct coupled
amplifier, but consisting of one NPN and one PNP
transistor. With flat frequency response, this line
amplifier amplifies recording inputs and playback
inputs prior to being applied to the Dolby amplifier.
Dolby Amplifier
The Dolby noise reduction system employed
in the CT-F615 is the Dolby B circuit. In the
mid and high frequency ranges where unwanted
REC/PB Head { 1301
CT-FG615
noise is more prominent, the level of input signals
whose input level is below a certain fixed level
(the Dolby level) is boosted prior to recording,
and automatically reduced again (by the same
amount) during playback. Tape hiss is also re-
duced by the same amount, resulting in the S/N
ratio being improved by up to 10dB in this region
(above 5kHz).
The Dolby processor in the CT-F615 employs
an IC (PA4005) developed by Pioneer. Unlike
more conventional Dolby ICs which utilize variable
resistance elements, the PA4005 employs a voltage
controlled variable gain circuit (VCA).
Recording Amplifier (107, 0108)
This circuit is another 2-stage direct coupled
amplifier consisting of an NPN and a PNP tran-
sistor. The input circuit has been equipped with
a low end compensatory circuit, the emitter with
a high end compensatory peaking circuit, and the
output circuit with a recording bias trap to prevent
flow back of recording bias.
HEADPHONE AMPLIFIER (0107, 0108)
This SEPP circuit consisting of 2 NPN tran-
sistors and a PNP transistor divides the output
signal by resistors in order to apply the same
signal to both the headphone output and the
meter amplifier.
Oscillator Circuit
An outline of the oscillator circuit is shown in
Fig. 7-1. When the front panel REC and PLAY
keys are pressed together, the IC301 REC output
is switched to high (H) level, resulting in a signal
being passed via R312, R309, Q304, and Q303,
thereby turning these 2 transistors on to start up
the oscillator.
Q301
Q302
Erase head
T3ilet
s 0504 R309 ——- R312
9303 +
MUTING
Fig. 7-1 Oscillator Circuit
13

Meter Amplifier
The level. meter circuit is outlined in Fig. 7—2.
The headphone amplifier output is amplified by
Q118 and rectified by D101, the resultant DC
component then being applied to IC501 (meter
drive).
This IC consists of 12 comparator elements
used for level display purposes. +B is applied to
the minus pole of the comparators to serve as
the reference voltage for each element, these
voltages being set at increasingly higher levels
for each higher level display segment. DC com-
ponents of the D101 rectified signal are compared
with the comparator reference voltages, resulting
in the lighting up of those segments where the
DC component is higher than the reference voltage.
SL 1
(PINCH SOL.) (RE So.)
0318 R348 D323
D320 0322
D316 B
AUTO STOP
circutt
D317
Headphone
(REW. SOL. )
" VR304
D314
Muting Circuit
12 segment
Fig. 7-2 Level Meter Circuit
(REO SOL. )
ao R356
iW
| R346 NK cE
op
Ul
ae
Q320
c335 {+
Ut 0319 stat 4
R347
R345 a
D336
+8
Recording amplifier muting
0330
0334
0337
LINE
OUTPUT
muting
A
D335
Bias
oscillator
S10
Si4 si2
Sry
R365
NO
HOLE | HOLE
S7 PLAY $10 REW siz ERASE PREVENT DETECTOR
$8 sToP S11 PAUSE S14 EJECT
So FF s$i2 REC Si6é TIMER
Fig. 7-3 Control Circuit
14
AUTO STOP circuit
eo

7.3, CONTROL CIRCUIT
See Fig. 7-3 for an outline of the control cir-
cuit.
Play Mode
1. When the PLAY switch S7 is turned on, pin
12 of IC301 is switched to H level, resulting
in +B being applied to Q315 via R346 and
D319, thereby turning the transistor on. .
2.The pinch solenoid SL1 is thus activated to
commence play mode.
Recording Mode
1. Load a cassette half with the erasure prevention
tabs still intact (in which case the erasure
prevention switch $138 will be in the NO HOLE
position). When the PLAY switch S7 switch and
REC switch S12 are turned on together, pins 12
and 10 of IC301 are switched to H level.
2. Due to the H level on pin 10, a current flows
via D330, R356, Q3820 and Q3819, thereby
turning these two transistors on. The REC
solenoid SL4 is thus activated, and the REC/PB
selector switch set to the REC position.
3. And as has already been described under ‘‘Os-
cillator circuit”, the bias oscillator circuit is
also activated when pin 10 of this IC is switched
to H level.
4. As a result of pin 12 being switched to H level,
pinch solenoid SL1 is activated as was described
above under ‘‘Play Mode’”’.
5.If the erasure prevention tabs of the loaded
cassette have been broken off (and S13 thus
switched to the HOLE position), pin 9 of
IC3801 will be shorted to ground, thereby
preventing pin 10 from being switched to
H level. _ Recording mode will therefore not
be possible.
Fast Forward (Rewind) Mode
1.When the FF switch S9 is turned on, pin 15
of IC801 is switched to H level, resulting in
+B being applied to Q317 via R851 and D324
to subsequently turn the transistor on.
2. The FF solenoid SL2 is then activated to start
fast forward mode.
3.The operation is basically the same during
rewind mode. Pin 138 of IC301 is switched
to H level when the REW switch S10 is turned
on, resulting in the activation of the REW
solenoid SL3.
Pause Mode
1.1f the PAUSE switch $11 is turned on during
playback or recording mode, pin 12 of IC801
is switched from H to L level, resulting in
@Q315 being turned off.
CT-F615
2. Pinch solenoid SL1 will thus be released, there-
by temporarily stopping tape transport.
Timer Start
@ Play Mode
1. The timer switch S16 is in the PLAY position
when the power switch is turned on by timer.
2. At the same time that the power supply voltage
rises, Q325 is turned on by the C844 charging
current.
8. And since pin 12 of IC3801 is at H level, current
will be applied to the base of Q315. However,
because of the time constant circuit consisting
of R348, C334 and R347, Q316 will be turned
on for 2 to 3 seconds, consequently keeping
Q315 turned off during this period.
4. Once C334 is fully charged up, Q316 is turned
off and Q815 turned on. Pinch solenoid SL1
is then activated to start playback mode.
® Recording Mode
1. The timer switch S16 is in the REC position
when the power switch is turned on by timer.
2.Pin 12 and 10 of IC301 are both switched to
H level at the initial onset of power. The REC
solenoid is thereby activated (since pin 10 is
at H level) and the bias oscillator started.
38. And as was described above for ‘“‘Timer Play
Mode’’, the pinch solenoid SL1 is activated
some 2 to 3 seconds after the power switch
is turned on.
Timing for Direct Switching Operations
To enable the CT-F615 to be switched direct-
ly from fast forward or rewind mode to playback
mode without generating tape slack or other
mechanical trouble, tape transport has been
designed to stop for fixed period of times during
such switching operations.
Direct Switching from Fast Forward (Rewind)
Mode to Playback Mode
1.Since pin 14 of IC801 is at H level during
fast forward (or rewind) mode, a charging
current is applied to C355 via D822. At the
same time, a current is also applied to Q316
via D822 and R349, thereby maintaining Q316
on.
2. When the PLAY switch S7 is turned on, pin
12 of IC301 is switched to H level, and pin 14
to -L level. The C835 discharge current, how-
ever, is applied to Q316 via R349 for about
0.3 seconds longer, thereby keeping this tran-
sistor turned on for that extra time. Activation
of pinch solenoid SL1 is thus delayed by that
same period of time.
15

Auto Stop Circuit
When tape transport stops, IC301 is put into
STOP mode, and the mechanism brought to a
stop by this auto stop circuit (see Fig. 7-4). Tape
transport detection involves a photo-interrupter
system — a runner (which cuts across a light beam)
coupled by belt to the take-up reel base.
1. During tape transport, the photo-interrupter
generates pulse signals by means of the rotating
runner. Consequently, Q310 is turned on and
off repeatedly, and C3382 charged up and dis-
charged with equal frequency.
2.When tape transport stops and the runner
ceases to rotate, the photo-interrupter stops
generating pulse signals, and the Q310 switch-
ing action stops. +B is then applied to C332
via R884 and R335 to charge up the capacitor.
8. Charging up of C332 is also accompanied by
an increase in the Q311 base potential, resulting
in the transistor being turned off. Q312 is
then turned on, and IC301 put into STOP
mode. Note that the auto stop circuit involving
Q313 and Q314 is activated during playback,
fast forward and rewind modes only.
1C304
Fig. 7-4 Auto Stop Circuit
16
7.4 MUTING CIRCUIT
See Fig. 7-5.
When Power Switch is Turned On
1.When the power switch is turned on, +B is
applied Q306 via R321 and C318. However,
Q306 does not turn on until C318 is charged
up about 3 seconds later.
2. Since Q307 is turned on at this time, +B is
applied to Q109 (Q209) via D316, Q307,
D302, and R170 (R270). And once Q109
(Q209) is turned on, the LINE OUTPUT is
muted.
3.+B is also applied via Q307 and D305 to Q114
(Q214) to mute the level meter. Furthermore,
by applying +B to Q106 (Q206) via Q307,
D306, and R146 (R246), the recording amplifier
is also muted.
Muting During Fast Forward, Rewind and Stop
Modes
1. Since both pin 10 and pin 12 of IC801 are
switched to L level during fast forward, rewind
and stop modes, the Q321 base potential is
dropped, resulting in this transistor being
turned on.
2.+B is then applied to Q306 via R358 and Q321
to turn Q306 on, resulting in the LINE OUT-
PUT, recording amplifier and level meter being
muted in the same way as when the power
switch is turned on.
When Switching from Stop to Recording Mode
This muting circuit mutes the noise generated
when the REC selector is switched, and therefore
prevents this noise from being recorded during
“after recording’’.
Although pin 10 of IC301 is kept at H level
during recording mode, current continues to pass
via R366, C345 and Q306 until C345 is fully
charged (taking about 0.8 seconds). So while
Q306 remains on, the LINE OUTPUT, record-
ing amplifier and level meter are muted.

{C301
CT-F615
Oscillator
circuit
Fig. 7-5 Muting Circuit
Recording
amplifier
7.5 TIMING CHART
NORMAL OPERATE
Pinch solenoid
Tape transport
Mechanical system
POWER
ON PLAY STOP FForREW |} STOP
-_—-
REC
REC/ POWER
pray | STOP | oFF
LINE
OUTPUT
muting
Recording
amplifier
muting
Amplifier
Power switch
on/off muting
T1; O.28sec
Fig. 7-6 Time Chart
T3; 0.31sec
17

18
DIRECT CHANGE
Mechanical system
Amplifier
Pinch solenoid
Tape transport
LINE
OUTPUT
muting
Recording
amplifier
muting
BIAS OSC.
T4.0.35sec 1T5:0.28sec T6:0.31sec T7:0,31sec T8:0.34sec
Fig. 7-7 Time Chart
AUTO START AUTO STOP
PLAY REC PLAY REC FF or
oTANe BY|/STAND BY / PLAY REW
Pinch solenoid
Tape transport
Mechanical system
LINE
OUTPUT
& {| muting
©
eo
£ | Recording
* amplifier
muting
ee -Eicfae
T12; 2.0 sec T13 5 3.1sec 714; 3.5sec T15; 1.5sec S16 ; 0.8 sec T17; 2sec
Fig. 7-8 Time Chart

CT-F615
8. MECHANICAL ADJUSTMENTS
8.1 PINCH ROLLER PRESSURE ADJUSTMENT
1. Put the deck into playback mode.
2. Gently push against the pinch roller arm with
a tension gauge (spring balance of approximately
500g full scale) and separate the pinch roller
slightly from the capstan.
3. Then ease the pinch roller back onto the cap-
stan, and read off the value when the pinch
roller starts to rotate. If the reading fails to lie
within 240 to 350g, replace the pinch roller
pressure spring (RBH-651).
f
Li ttial
Pinch roller
Fig. 8-1 Pinch Roller Pressure Adjustment
8.2 REEL BASE TORQUE ADJUSTMENT
Prior to Adjusting
Wipe both reel bases, the capstan shaft and the
pinch roller with Daiflon dipped in a little an-
hydrous alcohol.
Adjustment
Measure the torque with a torque meter during
playback, fast forward and rewind modes. The
measured values should normally lie within the
allowable ranges listed in the following table. If
the measured values lie outside the relevant ranges,
replace the take-up reel base ass’y (RXB-272)
and/or the drive arm ass’y (RXB-274).
Take-up Supply
reel base reel base
Playback mode | 35~55g-cm *2~6g*cm
F.F mode 70~120g-cm | *2~6g°cm
REW mode *2~6g°cm 70~120g°cm
* denotes back tension torque
8.3 TAPE SPEED ADJUSTMENT
1. Connect a frequency counter to the output
terminals.
2. Playback the 3kHz portion of the STD-301
test tape. At the beginning, the frequency
should lie within the 2995 to 3010Hz range,
and may be adjusted by turning the semi-fixed
resistor located in the capstan motor adjustment
hole (using a suitable size screw-driver). (See
Fig.8—2).
8. Tape speed is increased by turning the resistor
clockwise, and decreased by turning counter
clockwise.
Speed increased
Speed
Minus decreased
screwdriver
Fig. 8-2 Tape Speed Adjustment
8.4 PLAY SOLENOID ADJUSTMENT
1. Put the deck into playback mode.
2. Loosen screws @ and adjust the mounting
position of the play solenoid so that the square
hole of the head chassis ass’y fits flush against
the shaft bearing holder (i.e. 0 separation), as
shown in Fig.8—3.
Play lever
holder
Play
solenoid
bearing
0
Fig. 8-3 Play Solenoid Adjustment
193

8.5 F.F SOLENOID ADJUSTMENT
1.
2.
8.
1. Put the deck into rewind mode.
2.
8.
1.
2.
Put the deck into fast forward mode.
Loosen screws @ and adjust the fast forward
solenoid mounting position so that the square
hole of the reel base ass’y is flush against the
boss of the drive arm ass’y (i.e. 0 separation)
as shown in Fig.8—4.
6 REW SOLENOID ADJUSTMENT
Loosen screws @ and adjust the rewind solenoid
mounting position so that the boss of the drive
arm ass’y fits flush against the square hole of
the reel base ass’y (i.e. 0 separation) as shown
in Fig.8—4.
7 REC SOLENOID ADJUSTMENT
Put the deck into recording mode.
Loosen screws @ and adjust the recording
solenoid mounting position so that the record-
ing spring is stretched by 0.5 to 1mm as shown
in Feg.8—5.
Fast forward solenoid § Rewind solenoid
bn Gee
yer,
“Driving gear / Driving arm
ass’y
S reel base ass’y S reel base ass’y
idler gear
Driving gear
Fig. 8-4 Fast Forward and Rewind Solenoid Adjustment
20
Slide switch
‘Recording spring
Fig. 8-5 Recording Solenoid Adjustment

9. ELECTRICAL ADJUSTMENS
Before Starting Any Electrical Adjustments,
First Check Through the Following List of
Preparatory Items.
1.
9.1
. Connect the AC millivoltmeter to the OUTPUT
. Levels
. Unless
Electrical adjustments should only be com-
menced after all mechanical adjustments have
been completed.
during measurements are based on
OdBv = 1V. Connect a 50kQ (47 ~ 52k)
dummy resistor to the OUTPUT terminals.
. Designated test tapes must be used for all
relevant adjustments. Although both side A
and B of the test tapes have been prepared, it
is recommended that only side A (the side
with the label) be used.
STD-331A: general purpose during playback
mode.
adjustments during playback mode.
STD blank tape.
STD-608: CrO2 blank tape.
STD-604: METAL blank tape.
SONY DUAD C-60: Fe-Cr blank tape
STD-341A:
STD-601:
. Prepare the following measuring apparatus.
AC millivoltmeter, low frequency oscillator,
attenuator, oscilloscope.
otherwise specified, all adjustments
are for both left and right channels.
. Clean and demagnify the head.
. Leave the DOLBY NR switch off unless di-
rected otherwise.
. Let the deck warm up (aging) for a few minutes
before proceeding with the adjustments. Before
starting the recording and playback frequency
response adjustments, wait for about 3 to 5
minutes.
9.
CT-F615
Proceed with each adjustment in the specified
order. Altering the order can hinder proper
adjustment, resulting in loss of performance.
Adjustment Order
WoONIBAMA WHE
10.
- 204 333Hz
. Head azimuth adjustment
. Playback equalizer check
. Playback level adjustment
. F.L. meter adjustment
. Recording rough adjustment
. Erasure current adjustment
. Bias trap adjustment
. Recording bias rough adjustment
Recording/playback frequency response adjust-
ment/check
Recording level adjustment
LEVEL(d8)
333Hz
333Hr | 6.3kHz
100sec 00sec 50sec [00sec
Fig. 9-1 Test tape STD-341A
LEVEL (dB)
BOsec 30sec lOsec 10sec GOsec 10sec 30sec
Fig. 9-2 Test tape STD-331A
HEAD AZIMUTH ADJUSTMENT
terminals.
. Turn up the OUTPUT level control to maximum
position, and set the TAPE switch to the STD
position. Then turn VR101 (Lch) and VR201
(Rch) up to maximum positions.
.Play the 10kHz/—20dB portion of the STD-
831A test tape, and turn the head azimuth
adjustment screw so as to obtain maximum
output levels in both left and right channels.
. After completing this adjust, lock the screw
with “‘screw lock’’.
9.2 PLAYBACK EQUALIZER CHECK
1.
Again connect the AC millivoltmeter to the
OUTPUT terminals, and set the TAPE switch
to STD.
. Play the 333Hz (—20dB) and 6.3kHz portions
of the STD-341A test tape, and check that
the difference in output level between the two
is +0.5 + 1dB.
. Next set the TAPE switch to the Fe-Cr position
(or the CrOz2 or METAL position), and repeat
step 2. In this case, the 6.8kHz output should
differ from the 333Hz output level by —3.5
+ 1dB.
21

9.3 PLAYBACK LEVEL ADJUSTMENT
1.
and TP4 (Rch) of the mother ass’y. (The
OUTPUT level control may be set to any po-
sition).
2. Play the 333 Hz/OdB portion of the STD-341A
test tape, and adjust VR101(Lch) and VR201
(Reh) so that the AC millivoltmeter reads 1 dBv
(1.1V).
9.4 F.L METER ADJUSTMENT
1. Apply a 383Hz/—10dBv (316mV) signal to the
INPUT terminals with the deck in recording
mode.
2. Connect the AC millivoltmeter to TP1(Lch)
and TP2(Rch) of the mother ass’y, and adjust
the INPUT level control to obtain a millivolt-
meter reading of —23dBv (70mV).
3. Once the above settings have been completed,
turn VR3804 (mother ass’y) counter clockwise
to the point where the —20dB segment of
the F.L meter goes out (i.e. at the very instant).
4. Then adjust the INPUT level control to obtain
a millivoltmeter reading of —3dBv (700mV),
and adjust VR501(Lch) and VR502(Rch) on
the F.L meter ass’y so that the F.L meter
reads OdB (turn VR501 and VR502 around
clockwise and stop at the point where the
OdB segment lights up).
5. While turning the INPUT level control up gradu-
ally from minimum position, check that the
AC millivoltmeter gives the following reading
at the corresponding F.L meter positions.
F.L Meter Reading AC mV Meter Reading
—20aB 234 - aBv (56mV~112mV)
+5dB +2+2dBv (1V~1.58V)
Note: If the above ranges are not satisfied, repeat
steps 3 and 4 several times to readjust.
9.5 RECORDING ROUGH ADJUSTMENT
1. Apply a 333Hz/—10dBv (3816mV) signal to the
INPUT terminals with the deck in recording
mode. (Since the bias oscillator becomes
operable during: recording mode, short circuit
the base of Q304 to ground).
‘2. Connect the AC millivoltmeter to TP1 (Lch)
and TP2 (Rch) of the mother ass’y; and adjust
the INPUT level control so that the millivolt-
meter reads — 3dBv (700mV).
22
Connect. the AC millivoltmeter to TP3 (Lich)
3. Then set the TAPE switch to the STD position,
and connect the AC millivoltmeter to terminals
no.69 and no.70 (and then no.78 and no.79)
on the mother ass’y.
4. Adjust VR103 (Lch) and VR203 (Rch) so
that the millivoltmeter reads 0.84mV (834A).
9.6 ERASURE CURRENT ADJUSTMENT
1. Adjust VR303 on the mother ass’y to the
mechanical center position, and put the deck
into recording mode.
2. Turn the INPUT. level control down to mini-
mum position (but without short circuiting the
base of Q304 to ground).
3. Next set the TAPE switch to the METAL
position, and connect the AC millivoltmeter
to terminals no.41 and no.37 (ground) on
the mother ass’y. Adjust VR303 until the
millivoltmeter reads 180mV (180mA).
9.7 BIAS TRAP ADJUSTMENT
1. Put the deck into recording mode, and turn
the INPUT level control down to minimum
position.
2. With the TAPE switch still in the METAL
position, connect the AC millivoltmeter to
TP3 (Lch) and TP4 (Rch) on the mother ass’y.
Adjust L102 (Lch) and L202 (Rch) to obtain
minimum millivoltmeter reading.
9.8 RECORDING BIAS ROUGH ADJUSTMENT
1. Put the deck into recording mode and turn the
INPUT level control down to minimum po-
sition.
2. Set the TAPE switch to the STD position, and
connect the AC millivoltmeter to the mother
ass’y terminals no.71 and no.72 (and then
no.76 and no.77). Adjust VR3801 (Lch) and
VR302 (Rech) to obtain a millivoltmeter reading
of 3.4mV (340uA).
9.9 RECORDING/PLAYBACK FREQUENCY
RESPONSE CHECK AND ADJUSTMENT
1. Connect the AC millivoltmeter to the OUTPUT
terminals, set the TAPE switch to STD, and
turn the DOLBY NR switch off.
2. Apply a 338Hz/—80dB (31.6mV) signal to the
INPUT. terminals, and adjust the INPUT level
control to obtain a millivoltmeter reading of
—27dBv (44.6mV).
8. Record and then play back the 383Hz and
6.3kHz signal in the STD—601 test tape, and
adjust VR301 (Lech) and VR802 (Rch) to
obtain a difference in output level of +0.5dB.