Specified Line Control Setting; Dolby Fm/Copy Cal; Led Peak Level Indicator; Calibration - Teac A-450 Service Manual
Stereo cassette deck with dolby system
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Also See for A-450:
- Service manual (32 pages) ,
- Instruction manual (16 pages) ,
- Owner's manual (16 pages)
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7-2-2. SPECIFIED LINE CONTROL
SETTING
9.
Apply a 400 Hz signal at —-5 dB (435 mV) to the LINE
IN jacks. See Fig. 7-8.
10. Set the LINE controls to obtain the reading of 100 mV
(-18 dB) on the VTVM.
At this time, the physical
position of the LINE controls indicates the Specified
LINE Control Setting referred to in subsequent pro-
cedures.
IMPORTANT
After this setting is done, do not disturb the Specified
Control
Setting
of the LINE
controls
until
the
remaining checks and adjustments are completed.
7-2-3. DOLBY FM/COPY CAL CONTROL
SETTING
11. Set the DOLBY
FM/COPY switch to IN and apply a
400 Hz signal at -14 dB (154 mV) to the LINE IN
jacks.
12. Set the DOLBY FM/COPY-CAL controls on the A-450
rear panel to obtain the reading of 100 mV (—18 dB)
on the VTVM.
NOTE
When the DOLBY FM/COPY switch is IN, the LINE
and MIC
controls have no control over the input
signal and only the DOLBY FM/COPY CAL controls
(on the back
panel) can
adjust the input level.
However,
for the
convenience
of the following
procedure, do not disturb the LINE and MIC control
settings.
7-2-4, VUMETER
CALIBRATION
—RECORD-
13. Set the DOLBY FM/COPY switch to OUT and apply a
400 Hz signal at —5 dB (435 mV)
14, Adjust VR106/206 for +3 VU (D0) on the VU meter.
7-2-5. LED PEAK LEVEL INDICATOR
CALIBRATION
15. Adjust VR108
so that the PEAK LEVEL indicator
lights as shown in Fig. 7-9, when a 400 Hz signal is
applied at required level to the left channel LINE IN
jack. Keep the right channel LINE IN jack discon-
nected from an AF oscillator.
16. For the right channel, repeat the above procedure
except adjust VR208. Keep the left channel LINE IN
jack disconnected from the AF oscillator.
17. After setting both channels, make sure when required
signal is simultaneously applied to both channels, the
indicator reacts the same as above.
20
VTVM
OSCILLATOR
LINE IN
DOLBY B-TYPE PROCESSOR PC BD.
DECK under TEST
oe
Fig. 7-8 Connection
OSCILLATOR
PEAK
LEVEL
400Hr
(Indicator
ATTENUATOR
DECK
under TEST
t
ut
v lights at
(615mv)
-2
TT SEES tall intensity
(488mv)
-4
~---(@) goes ot completely
Specified
igut Lever C= —5
|
Fa
=
'
a
s
4
rs
:
>
z
PEAK LEVEL
indicator
Ta0o=
Fig. 7-9 LED Peak Level Indicator Setting
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