Tandberg TCD-420-A Service manual
TANDBERG'
n
TCD
CircuitDiagrams
42OA
with
Alignment Instructions
TANDBERG'-
The
European
Alternative
Electrical
checks and
adjustments
General
-
0
level
dB
0.775 V in
tapes.
1.2 V
in the RADIO
1.5 V in
tapes.
2.3 V in the OUTPUT
-
Before
and demagnetized.
path
is correctly
-
Carry
out
because
-
Remove
-
When
adjusting
adjustment,
Equipment
-
millivoltmeters
2
- Audio
- Frequency
- Distortion
- Wow
- Tandberg
- Measuring
Before
- MPX-FILTER (situated
and flutter
- No.
- No.
- No.
-
No.
- Maxell
- Maxell
- Fuji
adjusting,
defined
is
the RADIO
the OUTPUT
adjusting,
the adjustments
the
the base panel.
required
signal
meter
test cassettes:
(Speed check,
21
(Wow
22
(Azimuth
23
(Playback
24
cassettes:
UD XL I
UD XL II (Type
Metal
the tape
adjusted.
adjustments
the
the
top
generator
counter
meter
and flutter
or TDK Metal
set
buttons
as:
socket using Metal
It is necessary
Bias-traps
panel
adj. playb. head,
level
(Type I)
to OFF.
- Dolby
NR.*
to
Off.
socket, using Ty'pe I
sockets using Type I or II
sockets
at the back
using
path
must be
that the
in the
affect
1000 Hz)
adj., 1000 Hz)
II)
to:
order described
each other.
and the Bias-pre-
must
check, 3150 Hz)
MA
removed.
be
(Metal)
of the deck)
Metal
6300
or
tape.
tape.
cleaned
tape
Hz)
Before
II
Oscillator
The oscillator
kHz. The voltage
should
Metal
adjusting, fold
frequency
be
between 6
cassettes.
measured
page
out
is between
and 8
5.
and 100
80
on the erase head
volts
with Type
II or
Bias traps
-
Remove
Nleasure
C207
reading
Record/Playback
- Insert
standard
-
Set
millivoltmeter
sockets.
- Press
azimuth
maximum reading
Playback
- Insert
level
-
Adjust
R317/R417
(In
- If
you
on
RADIO
the
with a millivoltmeter
and
on the millivoltmeter.
Tandberg
a
azimuth
Monitor
the
Play
the
screw
panel.
top
adjust
head
button
to each channel
button. Adjust
shown in the figure
level
Tandberg
adjustment
with the
RADIO
the
test
1000 Hz).
PLAYBACK
1.5 V
to
socket, adjust
use a Dolby
the
OUTPUT
socket).
on
L101
and L201 to minimum
- azimuth
test
cassette
cassette.
to Taoe
on each channel.
cassette
No.
and
of the OTITPUT
the
No.
LEVEL ADJ.
on the
OUTPUT sockets.
to
level
cassette,
sockets
(0.615
C107
or a
23
connect
playback
to obtain
(Playback
24
775
mV.)
adjust
to
mV in the
and
a
1.2 V
- Output
*
The
words
Dolby
Noise
Lcvel
controls
"Dolby"
Laboratories
Reduction.
to
maximum.
is registrered trade marh
Inc.,
US.
Nfi
stands
for
of
(pre-adjustment)
Bias
-
Set
Adjust
Metal)
the
TCD
with
to
TPl and
420A
to record, Metal
R21031IJ.2203
approximately
TP2 (on
the
Osc.
(Bias
8 - 9 mV
board),
tape
loaded.
Adjustment
measured
see figure.
on
NOTE!
Adjusting the TCD
420A, using the
RADlo-socket.
Overall
Set
rator
and record
at this level.
-
-
frequency
theTCD
-
to
Rewind
Use the
on both
signals
30
a40OHz,
and
400
channels
are within
r3dB.
If
outside
|DJ.
back and
- If you
\?1991R2203,
R501/R601,
-
Make
the tolerance
M!,TAL.
check once
can not
a new recording,
more.
- Then
-
check the
18000
When
Hz.
the
the response
response
420A
to recording.
dB
(=
25
a
play
back.
Hz
signal as
that the
the
Then
make
more.
adjust to
BIAS ADJ.
TREBLE
frequency
frequency
with
the
with
Metal
tape
Adjust
mV
on the millivoltmeters)
10
kHz,
and
a 15 kHz
a reference
10 kHz
following
adjust
R2103/R2203
a
new recording,
and check
and 15 kHz
tolerance:
correct response
METAL,
ADJ. METAL.
play
back
and check
is
correct,
circuit
t
response
response
Dolby
NR.
the gene-
signal
BIAS
play
with
then
adjust
once
3 dB,
30
check
"On".
Distortion
-
Set
- Generator
- Metal
the TCD
to 1000 Hz
tape
420A
to recording.
(=
775 mV on the
milli-
voltmeters).
-
Rewind
-
Check
- If
outside the
BIAS
- Make
ADJ.
a new recording,
play
and
back.
that the distortion
tolerance,
METAL.
play
(
is
3%.
adjust R2103/R2203,
back
and check
once
more.
-
Then
check
within
Signal/noise -
-
The signal/noise
least
at
Dolby
IEC
as good
NR.
A-curve
IEC Linear
the
tolerance.
circuit
RMS
that
frequency
the
Metal tape
ratios at
as specified. Measure
"On".
68
56
3To
dB
dB
distortion
response
should
with
the
is
be
Recording
Connect
to the RADIO-socket.
Record,
400 Hz
-
Start
-
Rewind
maximum).
- The
mately
If
outside
while adjusting R105/R205,
as required.
Level
audio-generator
an
Metal
use
(= 450 mV
recording.
and
millivoltmeters
450 mV (-
the
Then
Metal
-
play
tolerance,
play back and check
tape
and two millivoltmeters
Set
the
Adjust
tape.
on the millivoltmeters).
(Output
back
should now read
to 0 dB).
2
make a new
REC. LEVEL METAL
TCD
420A
to
the generator
Level
controls
approxi-
recording
once more.
to
to
Program
-
Set the TCD
-
Record
(=11.2 V
program
ry3l9 _11th
RECORD.
meters
a
on
meters
Metal
-
420A
to Record.
400
Hz
signal from the generator
the millivoltmeters)
to 0 dB deflection
Rl35/R235,
tape
METER
and adjust
on
the Metal
LEVEL
ADJ.
the
^
Adiustments
for
type
I taPe
Adjustment
for
type
ll tape
.*\
/
Recording
Use
the millivoltmeter).
Record,
-
lf outside rhe
R529/R629,
R205'
- Make a new
more.
Overall
Use
-
on the millivoltmeters).
If outside
adjust
- Then check
Dolby NR. circuit
Distortion
- Record
millivoltmeters).
- Rewind
- Check that
If outside
LEVEL I and
- Then
distortion once
Level
level
same
the
rewind and
tolerance
REC. LEVEL
LEVEL
REC'
recording,
frequency
level
same
the
the tolerance,
R2101/R2201,
the
Hz at 0 dB
1000
play back.
and
the distortion
the tolerance,
R21021F.2202,
check
the
for Metal
as
play
(- 2 to 0
METAL'
play
response
as for
t
3 dB,
BIAS
frequency
"On".
adjust
frequency
more.
tape
back.
dB),
not
I. Do
back
and
Metal tape
- 18000
30
I.
ADJ.
response
(=
is
BIAS
mV
775
42%.
R529/R629,
ADJ.
response and
(= 450 V
adjust
touctr
check
(=
25
with the
on
I.
Recording
on
Rl05/
once
mY
Hz,
the
REC. LEVEL
the
- Use
on
- Record,
gutside
{
R104/R204,
Make a new recording,
more.
Overall
Use the same
the millivoltmeters).
outside the tolerance.
If
adjust
- Then
Dolby NR. circuit
Distortion
- Record
millivoltmeters)'
- Rewind and
-
Check
If outside
- Then
distortion
Level
level
same
the
millivoltmeters).
the
rewind
the tolerance,
freqeuncy
and
REC. LEVEL
response
level as
R21021R2202,
frequency
check
the
Hz
1000
that the distortion
the tolerance,
II and
check
once more.
at 0 dB
play back.
R2102/R2202
frequency
the
for Metal tape
as
play
back.
-
to 0
2
II.
back and
play
for Metal tape
t
BIAS ADJ.
"On".
adjust
30
3 dB.
response
(=
77b mV
(
is
2%.
R104/R204,
BIAS ADJ'
response
II.
(= 450 mV
adjust
dB,
check
(=
25
-
18000
with the
on
and the
once
mV on
Hz,
the
REC.
II.
Speed
Play
check
counter.on
counter).
If necessary, adjust
SPEED
check
Tandberg
back
Hz)
1000
the
ADJ. on the
and
output:
test cassette
(990
1%
control
with a
speed with
measure
t
to correct
Motor
No.
21
frequency
-
1010
board.
I
I
(Speed
on the
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