Teac A-4300SX - Page 18

8-21 OPTIMUM ERASURE MEASUREMENT
Tape SPEEDSW....... 7-1/2 ips (19 cm)
1.
Thread
the
TEAC
YTT-8003
Test
Tape
on
the
unit.
2.
Apply
a
1
kHz
signal
at
10
dB
above
the
operating
level
of
—8
dB
(975
mV)
to
the
LINE
IN
jack.
3.
Make
a
30
seconds
recording
of
the
above
signal
while
reading
and
noting
the
level
of
output,
then
rewind
to
beginning
of
this
recording.
4.
Disconnect
the
1
kHz
signal
source
(AF
oscillator)
from
the
LINE
IN
jack.
5. Connect a VIVM to the OUTPUT jack, through a 1 kHz
Narrow Band Pass Filter.
6.
Put
deck
in
the
Record
mode
and
“‘record”
(erase)
over
this
previous
recording,
then
rewind
to
beginning
again.
7. Put deck in Play mode and monitor the output on the
VTVM.
8.
Difference
in
output
level,
between
the
1
kHz
signal
and
the
‘‘no
signal”
section
level
should
be
more
than
68
dB.
NOTE: Filter loss should be considered.
OSCILLOSCOPE
OSCILLATOR
es DECK
under TEST F
Fig.
8-12
Test
Connections
for
Erase
measurement
8-22 CHANNEL SEPARATION
1. Be sure tape is completely bulk erased prior to doing
these checks.
2. Apply a 1 kHz signal at —8 dB (308 mV) to L chan.
3. Place deck in Record mode.
4. While recording measure the OUTPUT on Rchan. VTVM
connected through a 1 kHz Band Pass Filter.
Spec. should be 50 dB.
OSCILLOSCOPE
DECK
under TEST
ATTENUTOR
JouTPUT ikHz FILTER
° °
Fig. 8-13 Test Connections for Channel separation check
8-23 CROSS TALK REJECTION
(TRACK TO TRACK)
Following
is
the
measurement
procedure
at
7-1/2
ips
using
the TEAC standard tape, Type YTT-8023:
1.
Thread
a
blank
tape
or
the
YTT-8023
tape
on
the
unit.
2.
Apply
a
125
Hz
signal
at
—8
dB
(308
mV)
to
the
right
and left channel LINE IN jack.
3. Make a 30 second recording of the 125 Hz signal.
4.
Interchange
the
left
and
right
reels
and
rethread
tape
on
the
unit.
.
Connect
a
VTVM
to
the
right
channel
OUTPUT
jack.
6.
Playback
the
recorded
signal
portion
of
tape
and
moni-
tor
the
level
on
the
VTVM.
. The reading should be 4 8 dB.
8. Spec. should be 40 dB.
nn
—
8-25 DISTORTION CHECK
Tape SPEEDSW..... 7-1/2 ips (19 cm)
BIAS and EQSW ...........--- 1
9. Thread the TEAC YTT-8003 Test Tape on the unit.
10. Apply a 1 kHz signal to LINE IN jacks.
11. Place the deck in the record mode for about 10 seconds.
Rewind and play this recorded section of the tape.
12. Read the indicated value on the distortion analyzer.
13. The distortion factor should be 1.5 %.
OSCILLOSCOPE
AMPL. SPKR
DISTORTION ANALYZER
OSCILLATOR
DECK
under TEST
ATTENUATOR wey
Toes!
Fig.
8-14
Test
Connections
for
Distortion
check