Teac A-400 - Response and Ratio Checks

4-3-4. Record Level Setting
For CrO2 Tape: : For Regular Tape:
13. Installa TEAC MTT-505 test tape on the deck. 20. Repeat the above procedure, with the following exceptions,
14. Place the BIAS/EQ switches to the ‘1’ positions. for regular tape. ,
15. Apply a 400 Hz test signal at —12 dB (194 mV) to the LINE
IN jacks. Test tape: MTT-501
16. Place the deck in the record mode. BIAS/EQ switches: "2" position
17. Rewind and play this recorded section on the tape. Adjustments: VR104/VR204
18. Adjust VR105/VR205 to obtain 0 dB (0.775 V) on the
19.
VTVM. (Measured at OUTPUT jacks)
Continue __the process of the __ recording-rewinding-
playing-adjusting until this 0 dB (0.775 V) is obtained.
4-3-5. Distortion Checks DISTORTION ANALYZER
For CrO2 Tape:
i
- OSCILLATOR
The distortion factor should be: 3.0% or less.
DECK
under TEST
ATTENUATOR ‘NG
Connect a distortion analyzer to the OUTPUT jacks.
2. Connect an AF oscillator to the LINE IN jacks, through an . : : Tra94
aitannatar: Fig. 40 Distortion Check Setup
3. Load a TEAC MTT-505 test tape on the deck. .
4. Place the BIAS/EQ switches to the ‘'1” positions. For Regular Tape: ;
5. Apply a 400 Hz test tone at —12 dB (194 mV). 10. Repeat the above procedure, with the following exceptions,
6. Place the deck in the record mode. for regular tape.
7. Rewind and play this recorded section of the tape.
- 8. Read the indicated value on the distortion analyzer. Test tape: To
9. The distortion factor should be 3.0% or less. : BIAS/EQ switches: 2" positions
Distortion factor: 2.5% or less
x OSCILLOSCOPE
4-3-6. Overall Frequency Response
For CrO2 Tape:
1.
SVP
~ @
OSCILLATOR
Connect an AF oscillator to the LINE IN jacks, through an
attenuator, and a VTVM to the OUTPUT jacks.
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 a test signal from 40 Hz to 12.5 kHz at 42 dB (6.15
mV).
;
.
17390
Rewind
and
play
this
recorded
section of
the tape.
Fig.
41
Overall Frequency
Response
Check
Setup
DECK
under TEST
ATTENUATOR
°"@ @ @°
SO Oe:
Make certain that the reading obtained on the VTVM are I | TEST TAPE:MTT-5O5(BIAS/EQ 1)
ae ma ae m2 {~ —— DOLBY NR OUT
within the response limits. ; il fe ee ery
In case of any deviation in the high frequency range of the \ HI ee aes
. . 2 had t +
response limits, clean the heads and if this cleaning is ant mone
g 4 tH +
ineffective adjust L105/L205. 2 aa
w -2 1
a
u
a
es
#
1
-6 or ute a
P N-,
: il .
a [htt
SO 63 100 125 250 400 500 1K ak SK 63x 10K 125K
FREQUENCY IN Hz
Fig. 42 Overall Frequency Response Limits (for BIAS/EQ 1)
en OP a A SS SR A EP A POF AO TI,
18
' NOTE: For actual adjustment/test point locations, see page 21.