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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)
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