TANDBERG EDUCATIONAL TCR 222 User manual

TANDBERG
§DUCATIONAL
TCR
222
Service
Manual
Contents Page
1. Control functions ..........++++. 3
2.
Dismantling
........--..
eee
sees
3
3.
Regular
maintenance.......+-+.++>
5
4. Mechanical servicing .....--.+++-- 6
5. Circuit description. .......--.+.++- 13
6. Electrical adjustments..........-- 16
7. Diagrams. ......- ese eee cere eee 17
TANDBERG
=
CR
222
a
——
3
MOTORS
DUAL
CAPSTAN
——
REWIND STOP WIND PLAY RECORD EJECT

General specification:
Adjusted
for
Tandberg
Tape
or
any
other
high
equal
quality
tape.
Can
be
used
in
a
vertical
position
or
mounted
on
the
wall.
Dimensions:
Breadth
16
7/8”
(43.5
cm),
height
4
1/8”
(10.5 23 cm). Weight: 13.5 lb (6 kg).
Technical specification:
Power requirements: 230 V, 50 Hz.
Power consumption: 60 watts max.
Tape speed: 1 7/8 ips (4.75 cm/s).
Speed
tolerance
with
nominal
mains
voltage
and
normal
operating
temperature:
+
1%.
Wow
and
flutter,
max:
DIN
45500
peak
value
better
than
0.2%.
Frequency
response,
Tandberg
XD
tape:
40
—
14
000
Hz
(DIN
45500).
Signal/tape
noise
ratio,
DIN
45500:
Better
than
58
dB
(Gerduschspannung),
A-curve
and
better
than
55
dB
(Fremd-
spannung).
Distortion,
max.:
From
tape
at
0
dB
record
level:
3%.
Inputs:
MIC:
Suitable
for
dynamic
microphone
with
impedance
less
than
700
ohms.
Sensitivity
0.1
mV
to
17
mV
at
200
ohms.
RADIO:
Input
impedance
47
k
ohms.
Sensitivity
10
mV
to2
V.
PHONO:
Input
impedance
3
M
ohms.
Sensitivity
45
mV
to
5.0
V.
Outputs:
RADIO: Output voltage 0.8 V.
EXT.
SPEAKER
4
-
8
ohms.
Output
power
12
watts
in
4
ohms.
Tone
controls:
Treble control: -8 dB to + 8 dB at 10 000 Hz.
Bass control: -8 dB to + 8 dB at 100 Hz.
Transistors: 39.
Motors:
1
hysteresis
synchronous
motor
115
V,
50
Hz.
2
DC
winding
motors,
14
V.
IN ANY COMMUNICATION PERTAINING
TO THE EQUIPMENT, PLEASE SPECIFY
TYPE NUMBER AND SERIAL NUMBER

1.
CONTROL
FUNCTIONS
OUTPUT LEVEL. BASS — TREBLE. INPUT LEVEL. Adjust until the Program meter.
Volume control for Tone controls. program meter needle hits the edge Shows the level of
speaker(s). Use for of the red zone. Use for recording the input signal.
playback and when and when the TCR 222 is used as
TCR 222 is used as an amplifier for e.g. a microphone
an amplifier. program.
On/off indicator
lamp.
POWER.
On/off
button. Counter with
zero-button.
REWIND. PAUSE. For short
Fast backward pauses during record
tape winding. or playback.
STOP.
Stops the tape
WIND.
PLAY.
Press
to
playback
a
cassette.
RECORD.
Press
torecord
ona
EJECT.
Opens
the
cassette
Fast
forward
Control
speaker
volume
with
OUT-
cassette.
Adjust
until
the
program
compartment.
tape winding. PUT LEVEL knob. Set the INPUT meter needle hits the edge of the NB! The STOP button must be de-
LEVEL knob to 0 to avoid input red zone. pressed before the EJECT button
programs mixing with the playback NB! The PAUSE button must be can be used. Underneath the re-
program. depressed before the RECORD corder there is also a manual cassette
button can be used. eject lever that can be used when the
recorder is not connected to the
power supply.
2.
DISMANTLING
2.1
REMOVAL
OF
TOP
PANEL
1.
Release
the
cassette
compartment
by
pressing
the
EJECT
button,
or
operate
the
manual
cas-
sette
release
lever
as
shown
in
fig.
2.1,
2. Remove the plastic lid from the cassette com-
partment by pulling it upwards.
Push
the
compartment
down
to
closed
posi-
tion.
LOOK OK AGEL HOKOEROHSY
3.
Remove
3
screws
on
the
top
panel,
and
3
YRMORERG
0s
TrereRreee
este
NT
eEe:
DQAPHAHOKAOKATILOL KOOKS
PHIL POR OGAP EL HOKGOROH
Pen
screws
at
the
top
of
the
rear
panel
according
SPE
P
eR
PRET
to
fig.
2.2
SonezonoeRoreanesenoe
yy
awe
BRLE
SOK
AO
RPK
LYON
OKO
SHUOXAORDHSHOLGOKOKAOA
POXOKR SYS LSD KOKRAGALH SEY
KAGELESKOKAOAGHA WOR IO
PHLWOKEOAPK AYER AOKOKA
OX SOKOK AVE LEO KOK AOKESY
ROKRAGSLHSKOKAGKALS VOR,
VALS OHSK ROK SHAVES HOKE
SLELHOKOSALELHOKACAIA
2.
4.
Remove
the
top
panel
by
lifting
the
right
edge
first.
IMPORTANT! Note the position of the colored
wires before disconnecting the loudspeaker and the
mains indicator LED.
Fig. 2.2 Removal of top panel

2.2 REMOVAL OF SWITCH ASSEMBLY/
AMPLIFIER 2 BOARD
The Amplifier 2 Board is soldered onto the switch
assembly, and the switch assembly is mounted on
a bracket which is fastened to the front panel with
2 screws.
To remove the switch assembly/ Amplifier 2 Board,
see figures 2.3 and 2.4.
Proceed as follows:
Remove Amplifier 1 Board.
Remove 3 screws marked Al-A3.
Remove bracket B.
Remove the PAUSE switch button C.
Remove the switch assembly.
2.3 MOUNTING THE SWITCH ASSEMBLY/
AMPLIFIER 2 BOARD
Berfore mounting the switch assembly, make
sure that the transistor leads of Q 207 is not shor-
ted. Q 207 is positioned at the right side edge of
the board.
See fig. 2.4 and proceed as follows:
1. Re-install the assembly by plugging the con-
nectors at the bottom of the board.
Fasten assembly with screws Al and A2.
2. Place the lugs of lever D into slots E.
3. Re-install the PAUSE switch button C.
4. Operate the PAUSE switch button several
times to make sure that nylon slide F moves
far enough to allow the RECORD switch to
be operated.
5. Re-install bracket B and fasten with screw A3.
6. Re-install Amplifier 1 Board.
AMPLIFIER 1 BOARD
AMPLIFIER 2 BOARD
Fig. 2.3 Position of printed circuit boards
2.4
SERVICING
THE
AMPLIFIER
1
AND
AMPLIFIER
2
BOARDS
A special service kit consisting of two extender
boards is available, to simplify the servicing of
Amplifier 1 and Amplifier 2 Boards.
The
extender
boards
can
be
ordered
under
Part
No.
994
178.
m
Oo
co)
wo
Fig. 2.4 Switch assembly

3.
REGULAR
MAINTENANCE
3.1 CLEANING
The
parts
of
the
cassette
deck
that
are
in
contact
with
the
tape
surface
should
be
cleaned
regularly,
otherwise
the
sound
quality
will
be
greatly
reduced.
Cleaning
of
capstans
and
pinch
rollers
is
particularly
important
to
avoid
wow
and
flutter.
If
the
cassette
deck
is
used
every
day,
cleaning
should
be
performed
at
least.once
a
month.
The
cleaning
can
be
done
with
cotton
wool
or
a
piece
of
flannel
wrapped
around
a
small
stick
and
moistened
with
pure
alcohol
or
methylated
spirit.
A
kit
intended
for
this
purpose,
”
Tandberg
Profes-
sional
Tape
Head
Cleaner”,
is
available
under
part
no.
352
156.
NOTE!
Do
not
use
solvents,
such
as
acetone
or
trichlor-
ethylene,
as
these
may
damage
the
heads.
How to clean
1.
Release
the
cassette
compartment
by
pressing
the
EJECT
button
or
operate
the
manual
cas-
sette
release lever.
Remove
the
plastic
lid
from
the
cassette
com-
partment
by
pulling
it
upwards.
Push
the
cassette
compartment
down
to
closed
position.
9.
Clean
the
record/playback
head
(A),
erase
head
(B),
tape
guide
(C),
capstans
(D)
and
pinch
rollers
(E).
Do
not
use
too
much
cleaning
liquid
on
the
pinch
rollers,
and
dry
them
afterwards.
DO
NOT
USE
ANY
SHARP
OBJECTS
WHEN
CLEANING. DO NOT TOUCH THE ADJUST-
MENT SCREWS.
3.
Check
the
surrounding
area
for
dust
and
de-
posits
from
the
tape.
Clean
if
required.
Cleaning
should
be
performed
both
before
and
after
adjustments.
Fig. 3.1 Parts to be cleaned
3.2 DEGAUSSING
A marked increase in background noise from the
tape may indicate that the heads or other parts
in the tape path should have the residual magnetism
removed (degaussing).
If required, degaussing should be carried out as
follows. Switch off the deck. Remove the
cassette from the deck. Remove the plastic
cassette compartment lid and move the de-
gausser slowly past each one of the metal parts
normally in contact with the tape. Take great care
not to let the degausser touch the heads or metal
parts in the tape path. Do not switch off the de-
gausser until it is at least 3 ft away from the recorder.
Degaussing should be performed both before and
after adjustments.
3.3 LUBRICATION
The capstan motor and the reel motors rnay
require lubrication from time to time. T he
interval between each lubrication should. be
at least 3000 hours of operation.
Use the following types of oil:
Capstan motor: ANDEROL 465 fromTenneco
Chemicals, USA., or oil supplied by Tincherg,
under part no. 713 368.
Reel motors: NUTO H36 (also called SPENESSO
34) from Esso.
NOTE!
Use only one drop of oil for each moor.

4. MECHANICAL SERVICING
4.1 MICROSWITCH MS 1
Pinch rollers released:
Check that there is a gap of about 1 mm
between the connecting arm and the middle
leaf of the switch. See fig. 4.1.
Pinch rollers operated:
Check that the left and the middle leaf are
pressed together.
4.2 TAPE PATH ADJUSTMENTS
If parts in the tape path have to be replaced, a more or less
complete adjustment procedure should be carried out.
This adjustment procedure requires the use of special tools,
and should be carried out by a Tandberg representative.
If the tape path only needs minor adjustments, only visual
inspection and one single electric measurement is ordinarily
needed. Then see 4.2.1, "Outline of the adjustment proce-
dure’.
IMPORTANT! DO NOT USE MAGNETIC TOOLS
WHEN ADJUSTING PARTS IN THE TAPE PATH!
4.2.1 Outline of the adjustment
procedure
The following equipment is needed:
— Tandberg Test Tape No. 23 (Azimuth)
— Tandberg Test Tape No. 29 (Open cassette)
Instead of the Tandberg Test Tape No. 29, one may use an
ordinary high quality cassette which has been cut open,
so that the tape is visible. See fig. 4.2.
Insert Tandberg Test Tape No. 29.
Check that the tape does not climb” on the
capstans and is not bent or folded at the tape
guides. Also check that the tape does not ”bulge”
at the heads (”*bulging” indicates wrong azimuth
adjustment of the heads). When viewed from above
the tape should be seen as an almost invisible line.
Also check that the top of the erase head (Japan-
ese heads only) is flush with the top edge of the tape.
The erase head should not be visible above the tape.
If the erase head is made by Tandberg, and marked
with a Tandberg label, the top of the erase head should
be 0,82 mm above the top edge of the tape.
See fig. 4.3.
LG: |
coach ie
lever
> Bracket
ao *, i
gue arm
zi Pa P|
Fig. 4.1 Pinch rollers released
Fig. 4.2 Tandberg Test Tape No. 29
Open cassette
Erase head made
by Tandberg
Japanese made
erase head
Fig. 4.3 Adjusting the height of the erase head

If
erratic
tape
motion
is
observed,
try
to
eliminate
it
by
turning
the
adjustment
screws
for
heads
or
pinch
rollers.
Insert
a
Tandberg
test
tape
No.
23
and
adjust
with
the
screw
AZ
on
the
record/playback
head
to
maximum
output
signal
on
a
VIVM,
connected
to
the
RADIO
socket.
See
fig.
4.4.
4.2.2
Adjustment
procedure
The
following
equipment
is
needed:
—
Tandberg
Adjustment
Plate,
part
No.
713 537
—
Adjustment
Tool
No.
2,
part
No.
716
391
-
Adjustment
Tool
No.
3,
part
No.
716
406
—
Adjustment
Tool
No.
4,
part
No.
716
502
—
Tandberg
Test
Tape
No.
23
(Azimuth)
—
Tandberg
Test
Tape
No.
29
(Open
cassette)
Adjustment
Tool
No.
2
is
packed
with
the
adjustment
plate.
IMPORTANT!
Take
great
care
not
to
damage
the
head
fronts
when
using
the
tools
No.
2
and
3.
Ferrite
heads
are
easily
damaged.
DO
NOT
depress
the
PLAY-button
when
the
tools
are
in
use.
When
adjusting,
first
move
the
mounting
plate
with
the
pinch
rollers
and
the
heads
by
hand,
then
hold
the
mounting
plate
with
one
hand
and
move
the
tool
towards
the
head
with
the
other.
Be
sure
to
move
the
mounting
plate
strictly
horizon-
tally,
not
pressing
it
downwards
nor
lifting
it.
This is of great importance to the result of the ad-
justments.
4.2.2.1 Pinch rollers
Height.
Insert
the
Tandberg
Adjustment
Plate
and
move
the
mounting
plate
inwards
until
the
pinch
rollers
almost
touch
the
capstans.
Holding
the
mounting
plate
in
position
with
one
hand,
place
Tool
No.
2
on
the
Adjustment
Plate
as
shown
in
fig.
4.8.
Adjust
with
the
screw
P
on
roller
1
so
that
the
tip
of
Tool
2
fits
into
the
tape
guide
of
the
roller.
Also
adjust
the
two
screws
H
if
neccesary.
Turn
both
screws
equal
amounts.
Also
turn
the
azimuth
screw
AZ
correspondingly
in
the
op-
posite
direction
to
keep
the
roller
roughly
in
correct
azimuth
position.
Parallelity.
Remove
pitch
roller
1
and
look
at
figures
4.6
and
4.8.1.
for
the
following
procedure:
Install
Tool
No.
4
as
shown
in
the
figure.
The
capstan
should
fit
into
the
gap
of
the
tool.
Put
a
miniature
bulb
down
into
the
sylindric
hole
of
the
tool
.
The
light
from
the
bulb
shines
through
the
gap
to
simp-
lify
the
adjustments.
Fig. 4.5
Height
Azimuth Parallelity
Fig. 4.6 Parallelity of pinch roller
~,
wernt:
Ke
Fig. 4.7 Adjustment screws for firtch rollers
Fig. 4.8
Tandberg Adjustment Plate
with Tool No. 2
Fig. 4.8.1 B
Positioning
Tool No. 4 90°
aa &
CAPSTAN
PINCH ROLLER SHAFT Ol NO. 4

Move the mounting plate inwards. Adjust the screws H to
minimize the gap as viewed from direction A.
Observe the gap from direction B and adjust the screw AZ
so that the capstan is perfectly parallel to the tool, or at
least minimize the gap as far as possible.
By adjusting the screws H and AZ several times the capstan
should be perfectly parallel to the tool.
Adjust pinch roller 2 following the same procedure.
Adjusting height and parallelity without using Tool No. 4.
Insert Tandberg Test Tape No. 29, the open cassette.
Move the mounting plate inwards. Look at fig. 4.7 and
adjust with the screw P on roller 1 so that the tape fits into
the tape guide of the roller.
Also adjust the two screws H if neccesary. Turn both screws
equal amounts. Also turn the azimuth screw correspondingly
in the opposite direction to keep the roller roughly in cor-
rect azimuth position.
Adjust pinch roller 2 to corresponding height. This adjust-
ment is not critical.
See figures 4.6 and 4.7, and adjust with the screws P,
so that both rollers are in parallel with the capstans.
A white piece of paper can be inserted behind the pinch
rollers and the capstans to make in easier to observe the gap
between them. See fig. 4.6.
Check that the tape is not bent or folded at the tape guides,
or clims the capstans.. If neccesary, adjust the screw AZ.
Pinch roller operation. Remove the Adjustment Plate or
the cassette. Move the mounting plate inwards. Check that
both pinch rollers touch the capstans at exactly the same
time. The pinch rollers will start rotating when they meet
the capstans. If required, adjust the eccentric screw shown
in fig. 4.9.
4.2.2.2 Erase head
Preadjustment
of
head
mounting
plate.
Adjust
with
the
screws
H
and
AZ
shown
in
fig.
4.12
so
that
the
head
moun-
ting
plate
is parallel
to
the
underlying
mounting
plate.
The gap between them should be approx. 1 mm.
To check this the right chassis plate must be removed.
Adjustment of erase head made by Tandberg. Insert the
Tandberg Adjustment Plate and move the mounting plate
inwards. Keep the mounting plate in position with one hand.
Place Tool No. 3 on the Adjustment Plate according to
fig. 4.11.
See also fig. 4.12 and adjust the screws H and AZ so that
the top of the erase head is flush with the tool.
The front of the erase head should be parallel to the front
of the tool.
Adjustment of Japanese made erase head. Replace tool No.3
with Tool No. 2 and carry out the adjustment described
above.
Adjusting the erase head using Tandberg Test Tape No. 29.
In this case, insert the cassette and move the mounting
plate inwards. If the erase head is Japanese made, adjust
with the screws H and AZ as shown in fig. 4.12, so that the
top of the erase head is flush with the top edge of the tape.
If the erase head is made by Tandberg, and marked with
a Tandberg label, the top of the erase head should be
0.82 mm above the top edge of the tape. See fig. 4.3.
. Eccentric screw
Sf
oe
Fig. 4.9 Adjustment screw for pinch roller operation
Head
mounting
plate
Mounting plate
Fig. 4.11 Tandberg Adjustment Phte
with Tool No, 3.
Fig.
4.12
Adjustment
screws
for
the
erage
head

4.2.2.3
Record/
Playback
head
The
position
of
the
record/
playback
head
is
adjusted
by
turning
the
screws
on
the
head
bracket
shown
in
fig.
4.13.
Do
not
touch
the
adjustment
screws
on
the
head
mounting
plate,
as
it
isassummed
that
this
plate
has
already
been
cor-
rectly
adjusted
according
to
4.2.2.2
”Erase
head”’.
Height
and
parallelity.
Insert
the
Tandberg
Adjustment
Plate
and
move
the
mounting
plate
inwards.
Hold
the
moun-
ting
plate
in
position
while
placing
Tool
No.
2
as
shown
in
fig.
4.14.
See
also
fig.
4.13,
and
adjust
with
the
screws
H
and
P
so
that
the
tool
fits
into
the
tape
guide
on
the
head.
The
front
of
the
head
should
be
parallel
with
the
tip
front
of
the
tool.
Adjusting
height
and
parallelity
using
Tandberg
Test
Tape
No.
29.
After
having
inserted
the
cassette,
move
the
moun-
ting
plate
inwards.
See
fig.
4.13
and
adjust
with
the
screws
H
and
P
so
that
the
tape
fits
exactly
into
the
tape
guide
of
the
head.
The
front
of
the
head
should
be
parallel]
to
the
tape.
If
not
already
done,
insert
Tandberg
Test
Tape
No.
29,
the
open
cassette
shown
in
fig.
4.2.
Set
the
recorder
to
PLAY.
Check
that
the
tape
is
not
bent
nor
folded
at
the
tape
guides
and
does
not
bulge
at
the
heads.
Azimuth.
Insert
Tandberg
Test
Tape
No.
23
(6300
HZ).
Connect
a
VTVM
to
the
RADIO
socket
at
the
rear
panel.
Set
the
recorder
to
PLAY
and
adjust
with
the
screw
AZ
as
shown
in
fig.
4.13
to
maximum
output
reading
on
the
VTVM.
Finally,
check
the
height
and
parallelity
again.
Readjust
if
neccesary.
If
any
readjustment
is
made,
azimuth
must
also
be
checked.
4.3
REPLACING
THE
DRIVE
BELT
Before
starting
this
operation
remove
the
top
plate
and
the
cassette
compartment
lid.
1.
Wind
a
piece
of
sellotape
a
few
times
around
each
capstan
(see
fig.).
This
is
done
to
ensure
that
the
capstans
and
flywheels
will
stay
in
place
during
the
dismantling.
2.
Unhook
the
connecting
spring
from
the
mounting
plate.
Be
sure
to
note
which
notch
the
spring
is
fastened
to,
so
that
you
will
be
able
to
replace
it
correctly.
3.
Unhook
the
drive
belt
from
the
pulley.
Remove
the
circlip
on
the
front
side
of
the
cassette
compartment
(see
fig.).
5.
Unhook
the
locking
lever
from
the
cassette
compartment.
The
cassette
compartment
can
now
swing
upwards.
ape guide
pee & oy
NE ee)
L~ 9) Head bracket
HP sa iN Z
a ion Non f
Fig.
4.13
Adjustment
screws
for
record/playback
head
Fig.
4.14
Tandberg
Adjustment
Plate
with
Tool
No.
2.
Connecting spring
Mounting plate
{
Pulley |
Drive belt
i
i
i
4
\
{
| aes Locking lever
reed ,
s.
#
Fig. 4.16
Removing circlip from cassette confoartment

a or |
|e 7 fee : Guide bracket
we, oe re :
Fig. 4.17 Position of the guide brackets
6.
Unscrew
the
two
screws
(B)
holding
the
guide
brackets
for
the
mounting
plate.
Fig.
4.18
Unhooking
of
guide
brackets
7.
Unhook
the
two
guide
brackets
and
pull
them
out
through
the
holes
(C).
Flywheel mounting plate
(a
9.
Unscrew
the
three
screws
(D)
holding
the
flywheel
mounting
plate
and
—
—
lift
out
the
flywheel
mounting
plate
with
capstans
and
flywheels.
10. Remove the old drive belt.
11.
Place
the
new
drive
belt
around
the
flywheels
and
hook
it
around
the
cassette
guides
(see
fig.)
TAKE
CARE
NOT
TO
GET
OIL
OR
GREASE
ON
THE
DRIVE
BELT.
12.
Replace
the
flywheel
mounting
plateand
hook
the
drive
belt
around
the
pulley.
NOTE!
The
drive
belt
should
pass
under
the
courte
r
drive
belt.
13.
Replace
the
mounting
plate
and
check
that
it
runs
freely
back
and
forth.
Add
a
litte
grease
on
the
ball
bearings
if
required.
Use
Mobilplex
grease
No.
47
or
equvalent.
14.
Replace
all
other
parts.
Remove
the
s|Jotape
from
the
capstans
and
CLEAN
THE
CAP-
STANS
THOROUGHLY.
Insert
a
caset:te
and
check
that
the
tape
does
not
stick
to
he
capstans.

4.4
CASSETTE
ARM
The
cassette
arm
can
be
adjusted
by
bending
the
end
which
normally
rests
against
the
cassette
See
fig.
4.23.
Insert
a
cassette,
close
the
cassette
compartment
and
check
the
following:
—
The
cassette
should
rest
against
the
cassette
guides.
—
Microswitch
MS
3
should
be
closed.
(If
neces-
sary,
MS
3can
be
adjusted
by
bending
the
support
bracket
for
the
microswitch).
NOTE! If the cassette arm is bent too much to
the
right,
the
locking
lever
will
be
moved
so
far
to the left that it will not lock the cassette
compartment in the lower position.
—
When
the
cassette
compartment
is
released,
the
cassette
arm
should
push
the
cassette
half-way
out
of
the
compartment.
4.5
PINCH
ROLLER
SOLENOID
1. Set the deck to play.
9,
Check
that
the
connecting
spring
is
stretched
approximately
0.5
-
0.7
mm.
The
figure
shows
how
this
check
is
made.
(The
microswitches
are
not
shown
in
fig.
4.24.)
3.
If
necessary,
adjust
by
turning
the
nylon
screw
in
the
armature
of
the
solenoid.
To
reach
this
screw:
Switch
off
the
power,
lift
the
inner
top
plate
(with
the
indicators)
to
vertical
position.
Adjust
by
angling
the
screwdriver
towards
the
armature
from
the
left.
4,
Check
with
a
gauge
that
the
force
needed
to
lift
the
pinch
rollers
away
from
the
capstans
is
1000
-
1200
grams.
5.
If
necessary,
this
force
can
be
adjusted
by
moving
the
connecting
spring
to
another
notch.
If
the
spring
is
moved,
the
spring
tension
must
be
checked
again
as
explained
in
2.
~ is Adjust by
m uy bending here
| ut
. q a
wh ‘
H
Motor support plate
Support bracket
Loe
Fig.
4.23
Adjustment
of
cassetie
arm
Connecting spring
WWW
Spring lension
(cassette
deck
in
PLAY)
Place gauge fee ;
1000 - 1200 g
Fig, 4.24 Pinch roller pressir €

4.6 PAUSE SWITCH OPERATION
When the PAUSE button is depressed, the gap be-
tween pinch rollers and capstans should be approx.
0,5 mm, which can be adjusted with the screw
marked ”PAUSE ADJUST””. See fig. 4.25.
The screw can be reached by removing the right
side wall. Usea 1,5 mm ALLEN key when adjus-
ting.
Insert a cassette and set the deck to PLAY.
Depress the PAUSE button a few times, and check
the following:
—
The
PAUSE
lever
should
move
freely,
without
touching
the
motor
support
plate
or
the
bracket
of
the
PAUSE
switch.
If
required,
this
bracket
can
be
bent
a
little
with
a
screwdriver.
—
When
the
PAUSE
button
is
depressed,
the
tape
should
stop,
and
the
pinch
rollers
should
be
lifted
away
from
the
capstans.
The
gap
must
be
wide
enough
that
neither
of
the
pinch
rollers
touch
the
capstans
under
any
circumstance.
If
required,
adjust
with
the
PAUSE
ADJUST
screw.
—
At
the
same
time,
the
gap
must
be
so
narrow
that
the
pinch
roller
solenoid
will
pull
the
pinch
rollers
in again
when
the
PAUSE
button
is
re-
leased,
both
during
PLAY
and
RECORD.
a
an
PAUSE ADJUST
fig.
4.25
Position
of
the
PAUSE
ADJUST
screw
IMPORTANT!
With
the
deck
in
PLAY,
release
the
PAUSE
button
and
check
that
the
PAUSE
lever
can
be
moved
a
little
up
and
down
(as
indicated
with
an
arrow
in
the
figure).
If
the
lever
cannot
be
moved,
the
reason
is
probably
that
the
PAUSE
ADJUST
screw
butts
against
the
lever,
and
the
force
of
the
pinch
roller
solenoid
is
transferred
to
the
lever.
The
pressure
of
the
pinch
rollers
is
then
comespondingly
reduced.
Fig. 4.26 Checking the pause lever
4.7 ADJUSTING THE POSITION OF A
REEL MOTOR
Insert
a
high
quality
cassette
and
close
the
cassette
compartment.
Check
that
the
tape
spindle
on
the
motor
is
exactly
in
the
center
of
the
correspond-
ing
hub
on
the
cassette.
Try
the
recorder
in
play,
wind
and
rewind.
Check
that
the
hub
runs
easily
and
does
not
wobble.
If
necessary,
adjust
by
loosening
the
two
screws
holding
the
reel
motor.
This
will
be
easierif
you
remove
the
circlip
on
the
left
side
of
the
cassette
compartment
and
swing
the
cassette
compartment
upwards,
See
fig.
4.16,
page
9.
The
reel
motor
can
now
be
moved
slightly,
LL
N
Fig. 4.27

4.8
SALVAGING
TANGLED
TAPE
Occasionally
the
tape
will
wind
itself
around
the
last
of
the
two
capstans.
To
salvage
the
tape
proceed
as
follows:
1.
Remove
the
bottom
plate
of
the
deck.
2.
Turn
the
flywheel
of
the
entangled
capstan
slowly
against
its
normal
rotation.
Use
your
finger
to
turn
the
flywheel.
3.
When
the
tape
has
been
untangled
from
the
capstan,
wind
it
manually
onto
the
hubs
of
the
cassette.
4.9
REPLACING
THE
FLYWHEEL'S
UPPER
BEARING
A
special
tool
can
be
used
to
simplify
replacement
of
the
upper
bearings
for
the
flywheels.
The
worn-out
bearing
can
be
hammered
downwards
on
the
capstan.
It
needs
not
to
be
removed.
After
being
installed
onto
the
capstan,
the
new
bea-
ring
can
be
pressed
downwards
by
means
of
the
tool.
The
tool
is
available
under
part
No.
716
409.
Fig. 4.28 Turning the flywheel
in order to salvage tangled tape
5.
CIRCUIT
DESCRIPTION
5.1
HOW
TO
WIRE
THE
DIN
PLUGS
The plugs are seen
from the wiring side.
=) =
PHONO Shield connected to record MIC
ti Signal from receiver/amplifier
2 common (shield)
; s Signal to receiver/amplifier
— 1. Signal from mic.
—
<<
player
chassis.
C
‘
:
4-2.
Common
tead
ik
Se
edi
‘=8i
2.
Sereen
SS’
AL
ol
3
Signal
from
pick-up
<7
3.
Signal
from
mic.
we
8
,
‘

5.2 A SHORT EXPLANATION OF THE
SOLENOID OPERATING CIRCUIT
Q201, Q202.
Operation of the pinch roller (start) solenoid
should be slightly delayed, to give the reel motors
time to remove any slack in the tape, before the
pinch rollers are pulled in.
When both PLAY and RECORD buttons are re-
leased, C202 has no voltage and Q202(PNP) is cut-
off. Q201(NPN) has a base voltage of 0 V and is
also cut-off.
When the PLAY or RECORD button is depressed
the following sequence is started:
1. 13,5 Vis connected to the +side of C202. The
voltage drop over R202 gives Q202 an emitter
voltage of about 11 V. The transistor requires
a base voltage which is 0,7 V more negative than
the emitter to start conducting. The transistor
will therefore still be in the cut-off state.
2. C202 is charged through R206/R207. The posi-
tive voltage at point A is connected via C203 to
the base of Q202. This voltage is gradually re-
duced as C202 is charged.
moto tttn
BOARD NO. 63330 REWIND STOP
START/STOP 9
CIRCUIT
3.
After
a
short
period
of
time
the
voltage
at
piont
A
has
been
reduced
so
much
that
the
base
of
Q202
drops
lower
than
10,3
V,
and
the
transis-
tor
starts
conducting.
4.
When
Q202
starts
conducting,
the
collector
voltage
increases,
driving
Q201
into
conducting
state.
Point
B
is
connected
to
ground,
current
passes
through
the
”activate”
coil,
JB-3,
JB-4,
of
the
start
solenoid
and
the
pinch
rollers
operate.
When
Q201
is
conducting,
the
current
to
C202
passes
through
R205
and
Q201.
C202
will
there-
fore
be
fully
charged
in
a
very
short
time.
-
When
C202
is
fully
charged,
there
will
be
no
voltage
at
point
A.
C203
is
now
charged
through
R204.
The
current
through
R204
will
keep
Q202
in conducting state.
After
a
little
while
the
current
to
C203
has
been
reduced
so
much
that
Q202
goes
cut-off,
Q201
also
goes
cut-off,
stopping
the
current
through
the
”’activate”
coil.
R201
7-0]
t dE
Q202
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PINCH
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SUDE Sw.

5.3
A
SHORT
EXPLANATION
OF
THE
MOTOR
CONTROL
CIRCUITS
When
the
reel
motors
revolve,
they
generate
pulses.
These
pulses
are
used
to
control
the
motor
power
supply.
When both motors are stationary, no pulses are fed
to
the
motor
signal
amplifier.
Q
104
of
the
Schmitt-
trigger
is
cut-off,
and
Q105
is
conducting.
Q
107
is
also conducting, and the motor power supply is
connected to ground. Therefore, no voltage is fed
to the motors.
When the REWIND, WIND, PLAY or RECORD
button is depressed, one of the capacitors C201,
C204 or C205 will give a trigger pulse to the
Schmitt-trigger.Q104 starts conducting and Q105
goes cut-off. Q107 also goes cut-off, and the motor
power supply feeds a voltage to the motors (via
microswitches and operating switches). The motors
start
revolving,
feeding
pulses
to
the
motor
signal
amplifier. The output from this amplifier will keep
Q104 in conducting state.
During wind or rewind the supply motor works as
a generator, feeding a negative voltage to transistor
Q106 which regulates the motor power supply.
The voltage from the power supply is therefore
dependent on the speed of the supply reel.
When the tape stops (for instance at the end of the
tape) the input to the motor signal amplifier drops
to
zero,
and
the
Schmitt-trigger
reverts
to
unope-
rated state after a short delay (determined by
C104/R109). Q107 starts conducting and the
voltage from the motor power supply drops to zero.
5.4
CONTROL
OF
MOTOR
VOLTAGES
Remove
the
bottom
plate,
insert
a
cassette
in
the
deck
and
check
that
the
voltages
across
the
motors
are
as specified
below:
WIND motor REWIND motor
25V—-3V OV
O7V.—0.8:V | 0.7V =-0.8V
Drops to 0 Drops. to 0
after a'short after a short
while while |
10V—3.5V
Drops to 0.a
little while
after the end
stop is reached
Depress PLAY
10 V ~ 3.5 V
Drops to 0a
little while
after the end
stop is reached |
Trigger
Motor
Microswitches and operating switches power
Pw supply
Q107
Block diagram of motor control circutts

6.
ELECTRICAL
ADJUSTMENTS
EQUIPMENT
NEEDED:
QUIESCENT
CURRENT
High
impedance
voltmeter
(VTVM)
The
quiescent
current
can
be
adjusted
in
one
of
AF
signal
generator
EWO.
Wayes
DC
voltmeter
1.
Using
a
DC-voltmeter:
Distortionmeter
With
no
input
signal,
measure
across
R
174
and
:
Pandbens
Tee
Canseies
adjust
R
171
to
obtain
3-4
mV.
See
fig.
6.1.
an
:
— Test Tape No. 23 Azimuth 6300 Hz
— Test Tape No. 24 1000 Hz
:
R17
—
Tandberg
XD
cassette
or
equivalent
%
In
()
a
J é
(OMT MCMICENS|
é
C2 oe R321 = R312
LL}
+
GENERAL
Clean the tape path before making adjustments.
Carry out adjustments in the order described here,
since the adjustments affect one another.
NOTE
_——
Apply
10
mV,
1000
Hz
to
the
RADIO
socket
when
record
current
(sensitivity)
is
adjusted.
When playing back set the INPUT LEVEL to min.
so that the input signal does not disturb the play-
back signal.
Fig.
6.1
Location
of
test
point
and
AZIMUTH,
RECORD/
PLAYBACK
HEAD
adjustable
components
Play
back
Test
Tape
No.
23
or
a
standard
azimuth
2.
Using
an
AMP-meter:
cassette.
Adjust
the
azimuth
screw
on
the
record/
Unsolder
one
end
of
the
jumper
that
is
con-
playback
head
for
maximum
voltage
on
a
VITVM
nected
in
series
with
the
collector
of
Q
165.
connected
to
the
RADIO
socket.
See
fig.
6.2
to
identify
the
jumper.
OVERALL
RESPONSE
CURVE
(BIAS
ADJ.)
Connect
the
two
leads
of
an
AMP-meter
to
either
side
of
the
jumper.
With
no
input
signal,
Use
a
Tandberg
XD
cassette
or
equivalent.
adjust
R
171
to
15-20
mA.
With
1000
Hz
as
reference,
adjust
C112
BIAS
ADJ.
to
obtain
the
correct
curve
40-
14000
Hz,
-3
dB.
RECORD
CURRENT
(SENSITIVITY)
Play back Test Tape No. 24. Measure
the
output
voltage
on
the
RADIO
socket
with
the
VTVM
and
make
a
note
of
the
reading.
With
the
INPUT
LEVEL
set
to
maximum,
apply
10
mV
signal,
1000
Hz,
to
the
RADIO
socket.
Record
on
a
Tandberg
XD
cassette.
Play back the recorded signal.
The level now measured should be within 2,5 dB
of the level obtained with the No. 24 Test Tape.
If
not,
adjust
R
312
REC.LEVEL
ADJ.
and
try
again.
When this level is correct, adjust R321 METER :
LEVEL
ADJ.
to
obtain
0
dB
deflection
on
the
Fig.
6.2
Location
of
the
jumper
connected
in
level
meter.
series
with
collector
of
Q
165
Maximum
permissible
distortion
for
a
record/
play-
back signal at 0 dB is 3 %.

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6.6
Position
of
the
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BOARD
NO.
63330
REWIND
sToP
WIND
PLAY
RECORD
EJECT
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AMPLIFIER 2 BOARD
POWER AMPLIFIER
PLAYBACK AMP BIAS/ERASE OSCILLATOR
R217
START / STOP
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VOLTAGES
MEASURED
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THE
POSITION
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MICROSWITCHES
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4
(i
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DENOTES
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IS
SHOWN
IN
FIG.
6.6
AT
PAGE
18.
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tae
—
BC 547 2N 5087 BC 107 BC 486
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DENOTES
OC
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BC
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F
1 D 697
3
MEASURED
WITH
TANDBERG
TEST
TAPE
NR.24.
|
eth
80
697
80675 |
TRANSISTORS SEEN FROM UNDERNEATH
POWER SUPPLY, (AMPLIFIERS)
38V
Q182
2N 46919
(80176)
CRIB!
Bs0
€2200 Si
C184
Oly
SPEAKER
6-80
SPEAKER
5.
POWER
a
230V
SOHz
|
no°Cc
THERMAL FUSE
TCR 212
IN ANY COMMUNICATIO N PERTAINING
TO THE EQUIPMENT PL EASE SPECIFY
TYPE NUMBER ANDSEFRIIAL NUMBER
19 |

TANDBERG
=DUCATONML
TANDBERG INDUSTRIER A/S
EDUCATIONAL DIVISION
Olav Helsets vei 5, Oslo 6
P.O. Box 21 Bogerud
Oslo 6, Norway
3001.2.79 Part no. 714901
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