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ress the BIAS button.
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RECORD
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l~l
NAB
n
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ress the RE RO button.
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TW27A-5
TW27A-6
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Figure 4-4
Record Card Adjustments
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Page 4-4
If necessary, adjust the record card ' s LO< ,
MED<, or Hl< potentiometer, depending on
10. Check
the
record
card
high
frequency
equalization for a 0 VU level on the channel meter
of each channel.
9. Check the input calibration level for a 0 VU
reading on the channel meter of each channel.
ress the IN UT button.
Adjust the BIAS CAL potentiometer on the Bias
card for a 0 VU reading on the channel meter.
If necessary, adjust the IN CAL potentiometer
on the record card for a 0 VU meter reading.
If necessary, adjust the CAL REC poten
tiometer on the record card for a 0 VU meter
reading.
(On broadcast deck, adjust the LO LVL or HI
LVL potentiometer, depending on the selected
tape speed.)
Record the 1 kHz tone on the tape. Channel VU
meter should read 0 VU.
Record the 10 kHz tone on the tape. Channel VU
meter should read 0 VU.
For 30 ips, adjust the HI BIAS potentiometer
clockwise to drop the meter reading from its
peak reading by -1 dB for Scotch 250 or -1.5 dB
for Ampex 456 tape.
Record the 1 kHz tone on the tape. Channel VU
meter should read 0 VU.
from its peak reading by -1.5 dB for Scotch 250
or -3 dB for Ampex 456 tape.
11. Check the repro card low frequency equaliza
tion level for a minimum deviation from 0 VU on
each channel meter over the low frequency range.
Record the signal generator output on the tape.
Slowly vary the signal generator frequency
between 30 Hz and 100 Hz. Channel meter
movement should be centered around 0 VU.
the selected tape speed, for a 0 VU reading on
the channel meter.
If the meter swing is not centered around 0 VU,
adjust the LO> , MED> , or HI > potentiometer,
depending on the selected tape speed, to
center the movement while sweeping the fre
quency between 30 and 100 Hz.
RECORD
BDCST
Reset the signal generator for a 10 kHz signal at
+4 dBm.
® <
L0 @
Hl
8. Check the calibrated record level for a 0 VU
reading
on
the
channel
meter of
each
channel.
Adjust the signal generator output for 1 kHz at
+4 dBm.
ress the RE RO button.
LlNz-x
LO®
HI
LVL Q)
L0 Q)
MED
LIN z~x
O.L®
" EC ®
IN
CAL @
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HI z~x
-CL
IEC
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