CASSETTE DECK ELECTRICAL ADJUSTMENT
BEFORE ADJUSTMENT
Itthe tape surface which contacts the head, the capstan, and
thepinch roller, etc., isstained, itwillcause untable running
of the tape, wow and flutter, imperfect recording and erasing,
deterioration of tonal quality, and the tape jam around the
capstan, etc. Occasionally clean each part as follows;
1. Cut off power
2. Open the cassette lid.
3.
Wipe the head, the capstan, and the pinch roller with a
cotton
swab. If they are excessively stained, clean them
with the swab soaked in absolute alcohol or cleaning liq-
uid on the market.
MEASURING INSTRUMENTS REQUIRED
● Dualtrace Oscilloscope
● AC VTVM (AC voltmeter with high impedance)
● Frequency Counter
● Signal Oscillator
● Test Tapes
$
10kHz Test Tape (Example: TEAC MTT-1 14) for Azi-
muth Adjustment
$
3kHz Test Tape (Example:TEACMTT-111) for Normal
Tape Speed Adjustment
$
1.5kHz Test Tape (Example: A.BEX TCW-211) for
Double Tape Speed Adjustment
$
400Hz Test Tape (Example: TEAC MTT-150) for Play-
back Sensitivity Adjustment
● Test Tapes for Recording and Playback Operations
t
Normal Tape (Example: TDK AC 223)
$
CrOz Tape (Example: TDK AC 512)
:
Metal Tape (Example: TDK AC 712)
SWITCH POSITIONS
Unless especially indicated, set each switch as follows;
●
Input Level Volume
............................................... Center
● Surround Switch
....................................................... OFF
● Dolby NR Switch
....................................................... OFF
● Graphic Equalizer Controls .................................... FLAT
NORMAL TAPE SPEED ADJUSTMENT
1.
2,
3.
4.
Connect the frequency counter to the Dolby test point TP3
(Left
Channel) or TP4 (Right Channel) on the
DECK/FUNCTION P.C.Board.
Load Deck 1 with a test tape (Example: TEAC MTT-1 11)
and set it in the playback mode.
Adjust the potentiometer inside the capstan drive motor,
so that the output becomes 3000Hz *5 Hz.
Perform the same adjustment
for Deck 2.
HIGH SPEED TAPE SPEED ADJUSTMENT
1.
2.
3.
4.
5.
6.
7.
Connect the frequency counter to the Dolby test point TP3
(Left Channel) or TP4 (Right Channel) on the
DECK/FUNCTION P.C.Board.
Load Deck 1 with a test tape (Example: TEAC MTT-1 11)
and set it in the playback mode.
Short circuit Test Point TPI and GND on the
DECK/FUNCTION P.C.Board.
(The set will be set to the high speed mode.)
Adjust VR305 on the DECK/FUNCTION P.C.Board so that
the reading on the frequency counter is 6000Hz A1OHZ.
Load Deck 2 with the same test tape.
Short circuit Test Point TP2 and GND on the
DECK/FUNCTION P.C.Board.
Adjust VR306, so that the Deck 2 frequency should be-
come as same as Deck 1.
HEAD AZIMUTH ADJUSTMENT
1, Connect the dualtrace oscilloscope and AC VTVM to the
Dolby test point TP3 and TP4 (Left and Right channel) on
the DECK/FUNCTION P.C.Board.
,,,
Then, set the dualtrace oscilloscope as follows:
$ MODE ...............................................
CHOP (chopped)
~ SOURCE ........................... INT (internai), CH1 or CH2
t SWEEP MODE ................................. AUTO (automatic)
NOTE:
Adjust the field on the oscilloscope with the VOLT. ADJ. and
TIME ADJ.
2.
3.
4.
5.
6.
7.
Load Deck 1 with a test tape (Example: TEAC MTT-1 14)
and set it in the forward playback mode.
Adjust the forward head azimuth adjustment screw, so
that the wave forms become maximum on the oscillo-
scope and the Right channel wave form overlaps with the
Left channel one.
Set the unit in the
reverse playback mode and adjust the
wave forms as described above instructions with the re-
verse head azimuth adjustment screw
as well as the for-
ward.
uth
Fo
Repeat the above several time.
Adjust Deck 2 in the same way as for Deck 1.
After the adjustment, secure the adjusting screw with
paint or glue.
0
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