Teac A-5500 - Page 32

See eens Veer ee
ERASE EFFICIENCY
NOTE:
To
measure
erase
efficiency,
a
1
kHz
Band
Pass
Filter
(TEAC
M-206A)
must
be
used.
BPWNH
uw
LEVEL DEVIATION ( RECORD-PLAYBACK }
RECORD
AMPLIFIER
L’ M-826A
BAND PASS] ;
,_| FILTER | _|resr SET
' 1 kHz
OUTPUT M-0535
Fig. 11-11 Erase Efficiency Check Set-up
. Thread blank YIT-8003 or equivalent tape on the unit.
Apply a1 kHz signal at 0 dB to the LINE IN jacks.
Place unit in the RECORD mode and record this signal.
. Rewind the recording to the beginning and remove the AF
oscillator from the LINE IN jacks.
. Connect a Test-Set (M-826A) to the OUTPUT jack through the
1 kHz Band Pass Filter, select TAPE monitor.
Place unit in the RECORD MODE and "record" (erase) over this
portion of tape. Monitor the tape output on the Test-Set.
. The Test-Set should indicate -68 dB or less.
1. Thread a reel of blank high output tape and select 7-1/2ips
os
(19 cm/s).
Record
a
variety
of
frequencies,
such
as
400
Hz,
2
kHz,
5
kHz,
8
kHz,
10
KHz,
etc.,
at
the
specified
input
setting
with
the
RECORD
BIAS
switch
to
HIGH
position.
Record
approximately
10
seconds
of each
frequency.
.
During
playback
at
7-1/2ips
the
output
level
should
not
vary
more than 0.5 dB at 400 Hz, 1 dB at 10 kHz.
With
the
unit
tape
speed
at
3-3/4ips
(9.5
cm/s),
the
tolerances
are
the same as at 7-1/2ips.