Teac A-650 - Recording Performance Adjustments; Dolby NR Copy-Out-FM Switch Function Check; Bias Trap Adjustments

Preparations:
SPKR AMP
OSCILLATOR
VTVM
LIKE W
o o
Connection Fig. 6-11
Switch Setting:
5.
DOLBY NR
EQ
LIMITER
BIAS
6.
OUT
COPY
6-4. RECORDING PERFORMANCE
Preparations:
6-4-1. BIAS TRAP ADJUSTMENTS
Switch Setting:
EQ
LIMITER
DOLBY NR
BIAS
5.
Control Setting: Same as above section.
25
6-3-5. CHECKING OF DOLBY NR COPY-OUT-FM
SWITCH FUNCTION
7.
8.
9.
1.
2.
Load any recordable tape.
Place the deck in the RECORD-PAUSE mode with no
signal applied.
Adjust L101/201 for a minimum reading.
Change the VTVM connections to the CAL test point
and ground. See Fig. 6-12?
Adjust L703/803 for minimum reading on the VTVM.
Control Setting:
OUTPUT: Specified Setting (See 6-2-2)
Specified Setting (See 6-3-2)
Minimum Setting
DOLBY FM/COPY CAL controls (on the back panel)
can adjust the input level. However, for the conve 
nience of the following procedure, do not disturb the
LINE and M1C control settings.
3.
4.
1.
2.
3.
4.
NOTE
When the DOLBY NR COPY-OUT-FM switch is in
COPY or FM position, the LINE and MIC controls
have no control over the input signal and only the
NOTE
The VTVM used in this procedure must have load
impedance of IM ohm or more.
Load any recordable tape.
Place the deck in the RECORD-PAUSE mode.
Apply a 400 Hz signal at — 9 dB (274 mV).
Make sure the VTVM indication is -5 dB ± 2 dB (345
mV — 548 mV).
If the VTVM indication is out of specification, adjust
the DOLBY FM/COPY CAL controls (VR760/860)
on the A-650 rear panel.
Change the input signal to 10 kHz and also check for
-5 dB ± 2 dBon VTVM.
Set the DOLBY NR COPY-OUT-FM switch to FM.
Apply a 10 kHz signal at -17 dB (109 mV).
Confirm that the output level indicated on the VTVM
is — 5 dB ± 2 dB.
LINE:
MIC:
DECK
under TEST
4
OSCILLOSCOPE
o
j) O
'S' X
> > >
L —
ATTENUATOR
VTVM
EZ1
Specification:
When required input level is applied, Output
level should be — 5 dB ± 2 dB
NOTE
1. Before making any adjustments of the recording
circuit, be sure that all tests in the PLAYBACK
and MONITOR performance sections have been
accomplished. Die preceding performance should
be properly adjusted; otherwise record calibra 
tion would be inaccurate.
2. The adjustments and checks for Fe-Cr and Hi-Fi
tapes usually may be omitted unless the techni 
cian wishes to confirm that they also are within
specifications, except for the sections where
these tape are designated.
DECK under TEST **'
Fig. 6-12 Connection
O utput