Playback Performance; Specified Output Level Setting; Frequency Response - Playback - Teac C-1 Service Manual

6-3 PLAYBACK PERFORMANCE
6-3-1 RECORD/PLAYBACK HEAD
AZIMUTH ADJUSTMENT
OSCILLOSCOPE
DECK
under TEST
Fig. 6-2 Connection T-813
1. Load a TEAC MTT-316 test tape and play the 12.5 kHz
section on the tape.
2. During playback, slowly adjust the azimuth adjusting
screw (*in Fig. 5-20) so that the phase relationship be-
tween the L- and R-channels approximates O degrees as
indicated on the oscilloscope.
. At this time, ascertain that playback output level is ap-
proximately the maximum value on the AC voltmeter.
4. Then confirm that the phase difference of the respe-
tive frequency is within the rated value. 90 degrees or
less in the range of 40 Hz to 10 kHz is required.
5. Secure the screw with a drop of locking paint.
w
0° (IN PHASE) 45° 90° 180°
T-1493
Fig. 6-3 Confirming phase relationship
6-3-2 SPECIFIED OUTPUT LEVEL
SETTING
Specifications:
Specified output level: —5 dB (435 mV)
AC Voltmeter
TEST POINT i on
DOLBY DECODER
DECK under TEST
T-1491
Fig. 6-4 Connection
1. Load and play a TEAC MTT-150 test tape.
2. Adjust R121 on both L- and R-channels, for 580 mV
(—2.5 dB) on AC Voltmeter connected to test point 1
on the DOLBY DECODER.
3. Change the AC voltmeter connection to the OUTPUT
jack of L-channel.
4. Turn OUTPUT control so that the L-channel output
from the deck is set to produce the specified output
level of —5 dB (435 mV).
5. Change the AC voltmeter connection to the OUTPUT
jack of R-channel.
6. Adjust R896 for R-channel output of —5 dB.
OSCILLOSCOPE
AC Voltmeter | ,
VER
DECK
under TEST
SA Se
Fig. 6-5 Connection
6-3-3 FREQUENCY RESPONSE
— PLAYBACK —
CrO, tape
7. Load a TEAC MTT-316 test tape and play the 4th sec-
tion of the tape, voice labelled as 315 Hz, and note this
reading as a temporary reference level for the following
adjustments.
8. While playing the 10 kHz recorded section, adjust R112,
of both L- and R-channels, so that 10 kHz gives the same
level as the previous reference level in order to keep the
higher frequency signals within the given response limits.
9. Then play the required signals for comparison with the
playback frequency response limits chart.
10. Check that the readings obtained on the AC voltmeter
are within the response limits.
NORMAL tape
11. After achieving the above, set the EQ switch to NORMAL
and change the test tape to MTT-216.
12. Play the tape and check that the frequency response limits
for NORMAL tape are within the given limits.
NOTE: If the response does not meet the specified response
limits, the head should be checked for accumulated
oxide or dirt. If no dirt is found, the head azimuth
should be readjusted.
TOT TTTTIT T er Saat T TTiiMyt
TEST TAPE: MTT-316 (EQ, CrO, )
MTT-216 (EQ, NORMAL)
+2 |
AESPONSE IN dB
4050 700 35-500 K
FREQUENCY IN Hr
Fig. 6-6 Playback frequency response limits
SK 63K 10K 14K St
171360
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