Overall Signal-To-Noise Ratio; Erase Efficiency - Teac A-400 Service Manual

For Regular Tape:
9.- Repeat the above procedure, with the following exceptions,
for regular tape.
MTT-501
"2" positions
40 Hz ~ 10 kHz
L104/L204
Test tape:
BIAS/EQ switches:
Applied frequencies:
Adjustments:
RESPONSE IN 6B
Tot tt re T fey)
TEST TAPE:MTT—501HF(BIAS/EQ 2)
— DOLBY NR OUT
--~ DOLBY NR IN
ean
i
H
FREQUENCY IN Hz
4050 63 100 125
4-3-7. Overall Signal-to-Noise Ratio
For CrO2 Tape:
SO Or on
The overall S/N ratio should be: 45 dB (minimum)
Load a TEAC MTT-505 test tape on the deck.
Connect a VTVM to the OUTPUT jacks.
Place the BIAS/EQ switches to ''1" positions.
Read the indication on the VTVM.
For Regular Tape:
9.
4-3-8. Erase Efficiency
The overall S/N ratio should be: 44 dB (minimum)
Repeat the above procedure, with the following exceptions,
for regular tape.
The differences should be: 65 dB (minimum)
NOTE
1.
SEO SY ee ey
Load a TEAC MTT-505 test tape on the deck.
Place the BIAS/EQ switches to the "1" positions,
Place the deck in the record mode.
Apply a1 kHz signal at +7 dB (0.869 V).
NOTE:
10.
OSCILLOSCOPE
DECK
under TEST
T 369
Fig. 44 Overall S/N Ratio Check Setup
MTT-501
"2" positions
Test tape:
BIAS/EO switches:
OSCILLATOR
ATTENUATOR
@O@O@:
°
°
10.
11.
12.
DECK
under TEST
Hz FILTER
Es
Fig. 45 Erase Efficiency Check Setup