Teac A-400 - Playback Performance Verification

4-1-4, Peak Level Indicator Setting
15. Adjust VR106/V.R206 so that the peak level indicator lights
at full intensity when 400 Hz signal at —6 dB (388 mV) (+3 dB
above specified input level) is applied to the deck; and goes ©
off completely when the 400 Hz signal is reduced to —8 dB
(308 mV) (+1 dB above specified input level).
4-1-5. Headphone Output Level Checks
The value should be: -21 dB +2 dB (54.8 mV ~ 86 mV)
NOTE
These
checks
should
be
done
after
setting
the
specified
output
Adjust for PEAK LEVEL indicotor condition as shown on the right
OSCILLATOR * t
ve
TY. lights ot
8 yn KOY> cult intensity
AX
PEAK LEVEL
indicator
7
-e 4---- © goes off completely
ATTENUATOR ;
Si 8
|
|
PEAK LEVEL 7
Indicator Tae
VR206
RECORD control: Specified Setting
DECK under TEST
(PAUSE mode)
INPUT LEVEL (d8)
Fig. 29 Test Condition for Peak Level Indicator Setting
OSCILLATOR VTVM
level. (See 4-2-2.)
1. Connect test equipment to the deck as shown in Fig. 30. An
8 ohm non-inductive resistor should be used as the test load
resistor.
2. Load a TEAC MTT-505 test tape (blank).
3. Place the deck in the PAUSE mode.
4. Apply the 400 Hz signal at —9 dB and set the RECORD con-
trols to the specified setting position. (See steps in 4-1-1.)
5. Measure the level across the test load resistor.
The value should be —21 dB +2 dB (54.8 mV ~ 86 mV).
400Ht
ATTENUATOR
RECORD contro! : Specified Seting
DECK under TEST
(PAUSE mode)
Fig. 30 Test Condition for Headphone Output Level Checks
IMPORTANT
After
completing
alignment
of
the
monitor
circuit,
do
not
disturb
the
specified
input
level
position
of
the
RECORD
controls
unti!
the
remaining
checks
and
adjustments
are
com-
pleted.
“4-2. PLAYBACK PERFORMANCE
NOTE
Set the BIAS and EQ switches to position “2”, and the DOLBY
NR switch to the OUT position for this playback performance
alignment procedure.
4-2-1. Record/Playback Head Azimuth Adjustments
=
Connect an oscilloscope to the OUTPUT jacks as illustrated
in Fig. 31.
Connect a VTVM to either OUTPUT jack.
Load a TEAC MTT-150 test tape on the deck.
Play Dolby tone in the tape.
Make sure that the phase relationship between the 2 signals
(left channel and right) is within 45° on the oscilloscope.
Install a TEAC MT-T-116L test tape.
Play the 10 kHz/—10 GB signal section of the tape.
8. Slowly adjust the azimuth adjusting nut for the maximum
indication on the VTVM.
9. Secure the nut with a drop of tocking paint.
a Pew
PbAg2
Go "oe AS 90°
t
i
'
|
a
i
1
1 ae
1
t
IN PHASE OUT OF PHASE
Fig. 32 Confirming Phase Relationship
NOTE:
180°
OSCILLOSCOPE
DECK
under TEST
T> 389
Head Phase Check Setup
Fig. 31
Adjusting Nut
R/P Head
Fig.
33
Head
Azimuth
Adjustments
Location
For actual adjustment/test point locations, see page 21. 15