Aiwa AD-1800 User manual

Type:
Recording track system: 4-track, 2-channel
Circuit:
Power source:
Power consumption:
Frequency response:
SN ratio:
Wow & flutter:
Tape speed:
Recording system:
Erasing system:
Rewind time:
FF time:
Usable cassette tape:
Motor:
Head:
Input:
MIc:
SPECIFICATIONS
Hi-Fi stereo cassette tape deck LINE (iN):
with Dolby system and DNL
DIN (IN):
1 IC, 62 transistors, 43 diodes,
2 FET, 3 LED Output:
“EE” model LINE (OUT):
AC 110 ~ 120V/220 ~240V
switch changeable, 50/60 Hz
“UK” model
AC 120V/240V switchable 50 Hz DIN (OUT):
24W
LH tape, 30 ~ 14,000 Hz
Fe-Cr tape, 30 ~ 18,000 Hz Headphone:
CrO,
tape,
30
~
17,000
Hz
Dimensions
(w.h.d):
65 dB (Doiby NR/DNL ON, Fe-Cr Weight:
Accessories:
tape)
0.05% (WRMS}
4.76 cm/sec. (1-7/8 ips) 1.0%
AC bias
AC erase
95 sec. (w/ C-60)
95 sec. {w/ C-60)
C-30, C-60, C-90, (C-120)
AC hysterrisis synchronous motor
Ferrite guard head (FGH)
Max. input sensitivity: 0.25 mV
Impedance: 200 ohms ~ 10k ohms
Set using ISO screws
DATE OF ISSUE 25/12/1975
Max. input sensitivity: 50 mV
Impedance: 100 k ohms or higher
Max. input sensitivity: 0.1mV/k ohm
Impedance: 2.7 k ohms
Standard output level: 0.775V (O VU)
Optimum load impedance: 50 k ohms
or higher
Standard output level: 0.775V (O VU)
Optimum load impedance: 50 k ohms
or higher
Load impedance: 8 ohms
423 x 152 x 295 mm (with dust cover)
7.5 kg (with dust cover)
Dust cover x1
Tape cassette x1
DIN cord x1
Head cleaning pole x1
© The external design and the specifications are subject to
change without prior notice.
e@ Dolby Noise Reduction Circuit Under License from
Dolby Laboratories
Incorporated.
e@ The word ‘Dolby’ and “‘Double-D” symbol are trademarks
of Dolby Laboratories Incorporated.

MODEL
AD-1800EE,UK
AIWA
DISASSEMBLY INSTRUCTIONS
1.
To
Remove
Wooden
Cover
5.
To
Remove
Dolby-NR
Circuit
Board.
(1)
Remove
six
screws,
(1)
through
(6).
(1)
Pull
off
the
Dolby-NR
circuit
board.
(Refer
to
Fig.
1}
(Refer
to
Fig.
4)
6. To Remove DNL Circuit Board
(1) Pull off the DNL circuit board.
{Refer to Fig. 4)
Dolby NR Circuit Board
Dolby NR Circuit Board Sy
2.
To
Remove
Chassis
i"
<
Fig.
4
>
(1)
Pull
off
the
six
control
knobs.
(7)
REC/PB
Circuit
Board
(2)
Remove
six
screws,
(1)
through
(6).
(Refer
to
Fig.
2)
7.
To
Remove
Auto-Stop
Detectron
Circuit
Board.
{1) Remove two screws, (1) and (2).
(Refer to Fig. 5)
8. To Remove Auto-Stop/CrO, Switch Circuit Board
(1) Remove one screw (1).
(Refer to Fig. 6)
3. To Remove Jack-1 Circuit Board
(1) Remove three nuts ((1) through (3)) and unsolder lead 9. To Remove FF/REW Muting Circuit Board
of capacitor (4). (Refer to Fig. 3) (1) Remove two screws, (2) and (3).
(Refer to Fig. 6)
4. To Remove Rec./Pb Circuit Board
(1)
Remove
three
screws,
(5)
through
(7).
@
FF/REW
(Refer to Fig. 3) Muting circuit board
Auto
stop/
Cr02
switch
circuit
board

AIWA
MODEL AD-1800EE,UK
10. To Remove Switch/Volume Circuit Board
(1) Remove sixteen screw, (1) through (16).
(Refer to Fig. 7)
11. To Remove LAMP Circuit Board
(1) Remove one screw, (1).
(Refer to Fig. 8)
12. To Remove Meter Circuit Board
(1) Remove two screws, (2) and (3).
(Refer to Fig. 8)
13. To Remove Bias Osc Circuit Board
(1) Remove two screws, (4) and (5).
(Refer to Fig. 8)
14.
To
Remove
Stop
Muting
Circuit
Board
(1)
Remove
one
screw
(1).
(Refer
to
Fig.
9)
15. To Remove LED Circuit Board
(1) Remove two screws, (1) and (2).
(Refer to Fig. 10)
16. To Remove Counter Lamp Circuit Board
(1) Remove four screws, (1) through (4).
(Refer to Fig. 11)
< Fig. 11 >
17. To Remove Motor Circuit Board
(1) Remove two screws, (1) and (2).
(Refer to Fig. 12)
18. To Remove Jack-2 Circuit Board
(1) Remove the nut and washer (1).
(2) Remove six screws, (2) through (7).
(Refer to Fig. 13)

MODEL
AD-1800EE,UK
AIWA
Low level peak lamp lights
High level peak famp lights
NEW CIRCUIT DESCRIPTION
+7
2. Point Peak Indicators Since VU meter cannot follow,
indicated level is lower than actual.
—_
e@ Peak indicator circuit diagram
B +3
>
®
® od
ao
a
i:
=
BH
VU
meter
~
indication
Inadequate
damping
produces
higher
—_—
LEVEL
indicated
value
than
actual.
Input
waveform
TRi METER
" : Time —> .
af a . < Fig. 15>
e@ Recording Level Settings According to Tape
4—+ Distortion can be suppressed to below 3% and optimum
LED(L) LEDIM) recording performed by setting the recording levels as
® ry - 14 Bi follows.
HIGH ; F
cae
Ri
LOW
LH
Tape:
Lights
occasionally
at
+3dB;
does
not
light
at
TRS Re | +7dB
TR , Fe-Cr Tape: Lights often at +3dB; lights occasionally at
© = +70B
a
\
wy
ss
i
6
CrO2
Tape:
Does
not
light
at
either
+3dB
or
+7dB
i T I
Pr |seRe Zo i Ra |
Input and output level distortion characteristics
< Fig. 14 >
Presently employed VU meters are capable of indicating
continuous wave signals of approximately 300msec. They
are incapable of following faster pulse type signals however,
resulting in an indicated value considerably lower than the
actual! jevel. Thus if the recording level is set in reference to
the VU meters, an instantaneous high level input can cause
an over level, resulting in distortion.
Peak indicators are provided for preventing this situation
and are capable of indicating to about Imsec instantaneous
inputs. Earlier single point designs (a single peak indicator
which lights at +6VU) however, were ambiguous and
difficult to interpret. The indicator was not supposed to
light, but if it did not light, the level could not be
determined.
The 2 point peak indicator system employed in the
AD-1800 represents an improvement over earlier systems.
Two peak indicators are used with different lighting levels
(42.5~3VU and +6~7VU), allowing more accurate peak
indication.
@
Circuit
Description
ia)
Output level (dBm)
Distortion (%)
20
3 5 7
. gy |
Input
signal
(1)
is
amplified
approximately
10dB
by
TRt.
Dput
level
(dB)
<
Fig.
16>
Previously, it passed from (2) through the SFR and was
rectified and connected to the meter. However, since the
meter load is heavy, TR1 output voltage became varied by
SFR adjustment, preventing connection to the peak indi-
cator circuit.
TR2 is therefore inserted at that point as an emitter
follower, reducing meter amplifier output impedance in
order not to influence meter and peak indicators.
The signal to the meter amplifier is divided at (3). The peak
indicator signal is rectified at (4) and the voltage is applied
to SFR2. At this point the signal from the other channel is
mixed, while the peak indicator lighting level is determined
by adjusting SFR2.
When (6) reaches a specified voltage, TR3 and TR4
Darlingtons become on, and LED (L) lights. C1 is inserted
at this point to provide a certain degree of lighting time,
since instantaneous lighting with a pulse signal input would
be difficult to observe.
The voltage at (6) is divided at R3 & R4. By a higher level
than TR3 on level, TR5 and TR6 become on. R1 and R2
are inserted as protector resistors to control the current
flow through the LED.

AIWA
MODEL AD-1800EE,UK
=
Hall
IC
Tape
End
Detector
Circuit
In
order
to
remedy
the
drawbacks
(noise,
life,
maintenance,
etc.)
of
earlier
mechanical
contact
type
tape
end
detectors
(G.
switch
and
reed
switch),
a
magnet
and
Hall
IC
are
employed
in
the
AD-1800.
Previous
automatic
stopping
circuit
(|
®
; G.SW
|
| ~—
d+ ©
|
t
| GSW
| !
©
I
ic
1 AD-1500
oe
4600
@| Hall IC
1
Ring
magnet
Oh
AD-1800 < Fig. 17 >
e Automatic Stopping Circuit Diagram
When
a
magnetic
field
is
applied
at
right
angles
to
the
current
flow
in
a
Hall
element,
an
emf
(Hall
voitage)
becomes
generated
at
right
angles
to
the
magnetic
field
and
current
flow.
As
the
output
of
the
Hall
element
is
smail
(0.3V
at
|
=
20mA,
B
=
1000
Gauss),
the
AD-1800
element
is
incorporated
into
an
1C
amplifier
(more
than
2.5V
at
Icc
=
13.5mA,
B
=
350
Gauss).
< Fig. 18 >
Hall element
e@ Operating Description
The
waveform
at
point
(b),
shown
in
Fig.
19,
pertains
to
previous
automatic
stopping
circuits.
An
identical
waveform
can
also
be
obtained
from
a
ring
magnet
and
Hall
IC.
Six
magnetic
poles
are
provided
at
the
outer
circumference
of
the
ring
magnet,
producing
more
than
500
Gauss
at
2mm
from
the
outer
circumference.
The
magnetic
flux
pattern
through
1
rotation
of
the
ring
magnet
is
shown
in
Fig.
21.
Approx. 2mm
OFF OFF
+8
Ring
Peas
Hall
IC
|
|
ON
| |
)
vs
Point (b) waveform
<
Fig.
19>
<
Fig.
20
>
Circuit
board
x
2.
28
Oke
flux
5
PA
;
25
1
rotation
23
<Fig.21>
The flux variation through ring magnet rotation (coupled
with counter pulley rotation) imparted to the Hail IC
results in an output as shown in Fig. 22.
Zz 4
+ ®
> 3D
es 2
Sf
6 8. O8b=-2 fase
Transistor on level
< Fig. 22 >
lf this voitage were applied directly to TR1 base, the
transistor on and off times would differ, since the voltage is
2V even with 0 magnetic flux. R1 and R2 perform dividing
in order to equalize on and off times. TR1 collector output
voltage waveform (at b) becomes the waveform applied to
(b).
e@ Hall iC Handling Cautions
The Hall element is located within the IC as illustrated in
Fig. 23. If the magnet position becomes disturbed, or its
distance increased, the IC output declines. Caution is
therefore needed.
2:5
12.0
1. Vee
2. Output 1
3. Output 2
4. GHD
| 2 3 4 < Fig. 23>
Specified position is approximately 2mm from magnet.

MODEL
AD-1800EE
,UK
AIWA
ADJUSTMENTS
= = =©Mechanical Section
1. Thrust Adjustment
1) Turn thrust screw to move flywheel assembly vertical-
ly to obtain 0.2~0.3mm thrust. (Refer to Fig. 27}.
“ Thrust screw
0.2~0.3—
< Fig.27 >
2. Pinch Pressure
1} With set in play mode, apply 500g cylindrical tension
gage to pinch lever center. Press slowly and measure
pinch pressure when pinch roller separates from
capstan. (Refer to Fig. 28).
Rating: 400 +50g
< Fig. 28>
3. Pause Timing
1) Press FWD button for play mode, then slowly press
pause button. Observe stopping times of take up reel
hub and pinch roller rotations.
2) If pinch roller quickly separates from capstan, while
tape is running, adjust by bending pause lever in
direction B.
3) If pinch roller separation is delayed and tape winds
onto pinch rojler without take up reel hub rotation,
adjust by bending pause lever in direction A. (Refer to
Fig. 29).
Pause lever
Lock plate
< Fig. 29>
— Pinch lever spring
Supporting Plate Assembly Adjustments
Damper Adjustments
1) Screw damper shaft assembly fully into damper sup-
porting plate assembly (Refer to Fig. 30).
2) When damper shaft assembly is turned 2 rotations
clockwise, observe that shaft pin becomes positioned
toward square hole of supporting plate (Refer to Fig.
31}.
3) If shaft pin is in range A, turn counter-clockwise to
adjust; if in range B turn clockwise (Refer to Fig. 32).
Damper supporting plate assembly
< Fig. 32>
4-2 Supporting Plate Adjustment
Supporting plate
5.
1) Lock pin of tape selector lever should engage with
chrome lock plate when cassette elevating plate raises
during eject. Loosen supporting plate screw and adjust
by moving in A-B direction. Adjust so that lock pin
spacing from right side of chrome plate square hole
becomes 0.3~0.4mm (Refer to Fig. 33).
Chrome lock plate
< Fig. 33 >
Motor Pulley Thrust
1) Adjust by raising or lowering motor pulley so that
space between pulley rim and motor becomes 1mm
(Refer to Fig. 34).
Motor pulley
Driver
Motor
< Fig, 34 >

AIWA
er
eee
6. Tape Running
1)
Adjust
so
that
tape
does
not
contact
tape
guide
when
running (Refer to Fig. 35).
2)
{f
tape
contacts
upper
portion
of
guide
(Fig.
36).
move
adjusting
nut
in
direction
A
(Refer
to
Fig.
38).
3)
If
tape
contacts
lower
portion
of
guide
(Fig.
37),
move
adjusting nut in direction B (Refer to Fig. 38).
<
Fig.
35
>
<
Fig.
36>
<
Fig.
37
>
Adjusting nut
< Fig. 38>
7. CrO, Lock Plate
1)
Confirm
that
CrO,
lock
plate
separates
from
tape
selector
lever
when
cassette
elevating
plate
is
in
1/2
range.
2)
If
it
fails
to
separate,
adjust
by
turning
CrO,
lock
plate
adjusting
screw
clockwise
or
counter-clockwise
to
obtain
separation
in
the
1/2
range.
Apply
screw
locking
compound
after
adjusting.
(Refer
to
Fig.
39)
Cassette elevating plate
Tape selector lever
——CrOz lock plate
< Fig. 39 >
8. Tape Speed
3kHz +1%
Use a standard test tape, TTA-111A (3kHz) or equivalent.
9. Wow and Flutter
0.05% (WRMS) at PB
Use a standard test tape, TTA-11A (3kHz) or equivalent.
10, Take-up Torque
40 ~ 60g-cm
11.
FF
and
Rewind
Torque
90
~
1609-cm
12.
FF
and
Rewind
Time
90
+10
sec.
(at
C-60
cassette
tape)
13.
Automatic
shut-off
Time
4
+1
sec.
MODEL AD-1800EE,UK
CYCLE CONVERSION
Conversion Steps
1. Observe that POWER switch is OFF and AC cord
unplugged from power outlet.
2. Turn the set upside down, take out 3 screws from the
motor cover, and remove the motor cover.
3. Disengage belt from motor pulley and temporarily
position it on the motor fan securing screw.
4. Take out 2 motor pulley setscrews and remove motor
pulley.
5. Turn motor pulley upside down and reinstall it with
setscrews.
6. Engage belt on lower portion of motor pulley.
7. — Install motor cover.
e The thicker side of the motor pulley upward is for
60 Hz operation, while for 50 Hz operation, the
thinner side of the pulley should be upward.
50Hz —e 60Hz

MODEL AD-1800EE,UK
ADJUSTMENTS
ELECTRICAL SECTION
Preparations for Adjustment
Required Equipment
e@ Low frequency oscillator (signal generator}
e@ Variable resistance attenuator
e VTVM
@ Oscilloscope
e Resistors: 6002, 100k2, 27k2, 5.6k2
e Test tapes: TTA-117E/TTA-161/TTA-119D (CrO2)/TTA-
119E (FeCr)/TTA-119A (LH)
Adjustment Cautions
1) Before adjusting, clean heads, capstan and pinch roller
with gauze moistened in alcohol.
2) Demagnetize record/play head with head eraser.
3) Thoroughly demagnetize adjusting driver.
4) Set playback volume to maximum.
5) Except where otherwise indicated, set DOLBY-NR
and DNL switches to OFF, employ MIC jacks for
input and LINE OUT for output.
6) Standard inputs (OdB = 0.775V)
MIC Jack: 65dB
LINE-IN: 20dB
7) Connect 100k load resistor to LINE-OUT.
@ Main Component Locations
LIO4 = LIO6
Se pe
PLAYBACK ADJUSTMENTS
1. Azimuth
TAPE SELECTOR: CrO2
Play 10kHz portion of test tape TTA-117E (CrO2) and turn
azimuth adjusting screw to obtain maximum output from
left and right channels.
Do not rotate screw more than 1/4 turn.
After adjusting, apply locking compound to screw.
2. Playback Frequency Response
TAPE SELECTOR: CrO,
Play test tape TTA-117E (CrO2) and adjust high frequency
trimmer resistor SFR101 for equal outputs at 1kHz and
10kHz. In the same manner, adjust SFR102 for the right
channel.
Rating: 1kHz~10kHz flat
3. Level Meters
With set in record mode, apply 400Hz +25dB signal. Adjust
LINE IN volume for 580mV output from TP-3,
Adjust meter trimmer resistor SFR201 so that level meter
indicates the Dolby mark, In the same manner, measure
TP-4 and adjust SF R202 for the right channel.
4. Playback Level
TAPE SELECTOR: LH
Play test tape TTA-161 and adjust playback output
trimmer resistor SFR103 so that level meter indicates the
Dolby mark, In the same manner, adjust SFR104 for the
right channel.
RECORDING ADJUSTMENTS
1. Bias Trap Coil
TAPE SELECTOR: CrO,
With set in recording mode, adjust trap coil L107 for
minimum voltage at test point TP-5. In the same manner,
measure TP-6 and adjust L108 for the right channel.
2. Dolby Trap Coil
TAPE SELECTOR: CrO2
With set in recording mode, adjust Dolby trap coil L101 for
minimum bias leakage to LINE OUT. In the same manner,
adjust 102 for the right channel.
3. Bias Current
TAPE SELECTOR: CrO,
With set in recording mode, adjust bias current trimmer
TC701 for 2mV (200uA) voltage at test point TP-1. In the
same manner, measure TP-2 and adjust TC202 for the right
channel.
Rating: 2mV (200uA)

AIWA
4.
Record/Piayback
Frequency
Response
a
ar
~
We
L206
¢
L
202
:
3
L205
203
L20l
1)
CrO,
TAPE
SELECTOR:
CrO,
Test
Tape:
TTA-119D
Apply
500Hz
(—25dB)
signal
via
LINE
IN
jack
and
adjust
line
volume
for
77.5mV
output
at
LINE
OUT,
Record
5OOH2z
and
SkHz
signals
on
test
tape
TTA-119D
and
play
back.
Confirm
that
the
1kHz
level
is
within
+0.5dB
in
respect
to
the
500Hz
level.
If
the
5kHz
level
is
higher,
set
the
bias
current
higher
than
amv.
lf
the
SkHz
level
is
lower,
set
the
bias
current
lower
than
amv
Perform
adjustment
in
the
same
manner
as
described
in
Step
3
Bias
Current
adjustment.
Record
and
play
back
500Hz,
5kHz,
10kHz
and
15kHz
signals.
Adjust
CrO,
hi
peaking
coil
L201
so
that
with
respect
to
the
500Hz
signal,
5kHz
and
10kHz
become
within
+0.5dB
and
15kHz
within
+1dB.
In
the
same
manner,
adjust
L202
for
the
right
channel.
2)
Fe-Cr
Test
Tape:
TTA-119E
TAPE
SELECTOR:
Fe-Cr
Record
and
play
back
with
TTA-119E
test
tape
as
described
for
CrO2
in
step
1.
If
results
are
not
within
ratings,
adjust
as
follows.
Playback
Level
(1kHz
ref.)
Connection
|
Bias
Voltage
5kHz
level
higher
(1)
Increases
5kHz
level
lower
Decreases
Short
one
of
the
circuit
patterns
among
1~3.
Record
and
play
back
500Hz,
10kHz
and
15kHz
signals.
Adjust
FeCr
hi
peaking
coil
L203
so
that
with
reference
to
the
500Hz
level,
10kHz
becomes
within
+0.5dB
and
15kHz
within
+1dB.
In
the
same
manner,
adjust
L204
for
the
right
channel.
3) LH-NORMAL
Test Tape: TTA-119A
TAPE SELECTOR: LH-NORMAL
Record
and
play
back
with
TTA-119A
test
tape
as
described
for
CrO,
in
step
1.
If
results
are
not
within
ratings, adjust as follows.
Playback Level (1kHz ref.)
Connection | Bias Voltage
Increases
5kHz level higher
5kHz levei lower
Decreases
Record
and
play
back
500Hz
and
10kHz
signals.
Adjust
LH
hi
peaking
coil
L205
so
that
with
reference
to
the
500Hz
level,
10kHz
becomes
within
—1.5
+1dB.
In
the
same
manner,
adjust
L206
for
the
right
channel.
1)
2)
3)
5.
MODEL
AD-1800EE,UK
Record/Playback Level
CrO,
Test Tape:
TAPE SELECTOR:
TTA-119D
CrO2
With set in recording mode, apply 2kHz 77.5mV signal.
Record and play back this signal on TTA-119D test tape.
Adjust CrO recording current trimmer resistor SFR205 so
that playback level becomes 77.5mV +0.25dB. In the same
manner, adjust SFR206 for the right channel,
Fe-Cr
Test Tape: TTA-119E
TAPE SELECTOR: Fe-Cr
Employ TTA-119E test tape and perform the same opera-
tion as for CrOz above. Adjust SFR207 for the left
channel, and SF R208 for the right channel.
LH-NORMAL
Test Tape: TTA-119A
TAPE SELECTOR: LH-NORMAL
Employ TTA-119A test tape and perform the same
operation as for CrOz. Adjust SFR 209 for the left channel,
and SFR210 for the right channel.
Peak Indicator
With set in record mode, apply 1kHz —27dB signal, Adjust
LINE IN volume for OVU indication on level meter. Set
attenuator to —21dB (level meter indicates +6dB) and turn
the peak indicator trimmer resistor SFR203 to the point
where the red peak indicator just extinguishes.
Next set attenuator to —20dB and confirm that red
indicator lights. Vary attenuator in the —24dB area and
read the value at the point where yellow indicator just
extinguishes.
Rating: —25dB +1.5dB
SFR20}
SFR202
MPX Filter
With set in record mode, apply 19kHz signal to LINE IN.
Adjust LINE IN volume for 0.77V at LINE OUT. With
MPX filter switch of Dolby NR ON, adjust MPX filter coil
L105 so that 19kHz signal becomes less than —30cB. !n the
same manner, adjust L106 for the right channel.

MODEL
AD-1800EE,UK
DOLBY NR ADJUSTMENTS
e Main Component Locations and Connections
o™
«-_™
SFR303 SFR301
(3049) (302)
OOLBY-NR
CIRCUIT BOARD
PB
ee lS am
—* AM o
P ‘
REC/PB : Bei 1
o
REC $
OPEN oP VTVM
GATE
oc2av
!
oo 0 O-
SHORT
ON
DOLBY-NR eel Ie
pe
OFF
1) Remove Dolby NR circuit board from set and connect
as shown in drawing.
2) Turn SFR301 (302) and SFR303 (304) fully in the
directions shown by arrows.
3) Position switches as follows.
REC/PB: PB
GATE: OPEN
DOLBY-NR: OFF
4) Apply 400Hz signal and adjust attenuator so that
output becomes 7.6mV, then read attenuator value.
Rating: —49dB +1dB
5) Set REC/PB switch to REC and confirm output level
difference of +0.25dB. Next at frequencies of 100Hz,
1kHz and 10kHz, confirm an output level difference
of +1dB.
6) Position switches as follows.
REC/PB: PB
GATE: SHORT
DOLBY-NR: OFF
7) Apply 5kHz signal and adjust attenuator so that
output becomes 7.6mV, then read attenuator value.
Rating: —49 +1dB
Next set DOLBY-NR_ switch to ON and adjust
SFR303 (304) for 2.4mV output.
8) At the above (step 7) condition, set GATE switch to
OPEN and adjust SF R301 (302) for 3mV output.
9) After adjusting, apply locking compound to trimmer
resistors.
GIG. GEN
10
AIWA
ELECTRICAL MEASUREMENTS
PREPARATIONS FOR MEASURING
Required Equipment
® Low frequency oscillator
® Variable resistance attenuator
® Oscilloscope
® 6002 and 100k2 resistors
® Distortion meter
® Wow meter
@ 1kHz bandpass filter
@ Test tapes: TTA-116/TTA-114/TTA-119D (CrO,)/TTA-
119E (Fe-Cr)/TTA-119A (LH)
Connection
WOW METER
MIC. JACK
S!IG.GEN ATT
<~—
LINE OUT
100KQ
Bandpass filter eM
Measuring Cautions
1) Before measuring, demagnetize rec/play and erase
heads with head eraser and clean heads with gauze
moistened in alcohol.
2) Set playback volume to maximum.
3) Standard inputs (OdB = 0.775V)
MIC jack 65dB
LINE-iIN 20dB
4) Connect 100k load resistor to LINE OUT.
Playback Output
Play test tape TTA-161 and measure output level.
Rating: 1.03V +0.5dB
Recording/Playback Distortion
Apply 400Hz signal via MIC jack and adjust attenuator for
OVU indication on set VU meter. Record this signal on test
tape and measure playback distortion.
Ratings:
TAPE
Test T
ers SELECTOR
Distortion
TTA-119D (CrO tape)
TTA-119E (Fe-Cr tape) | Fe-Cr
‘| TTA-119A (LH tape) LH-NORMAL |} Less than 1.5%
Less than 2.5%
Less than 1.0%