Teac A-4070G - Bias Adjustment

BIAS ADJUSTMENT
NOTE
Perform bias trap adjustment before proceeding. These
adjustments are only made at 7-1/2ips tape speed. The
bias oscillator frequency is 100 +10 kHz.
HIGH position
i
lo
Thread record test tape SCOTCH 203 on the unit.
Place
the
RECORD
MODE,
EQ
and
BIAS
switch
to
HIGH
and
the
unit
in the record mode.
- Place the OUTPUT switch in the TAPE position.
- Apply a 400 Hz signal at -8 dB to the LINE IN jack.
.
Adjust
capacitor
FORWARD
VC-101,
VC-201,
REVERSE
VC-103,
VC-203
for a peak on the level meter.
Turn
the
capacitors
clockwise
until
a
decrease
of
0.5
dB
is
obtained.
NORMAL position
7.
8.
9.
Adjust
capacitor
FORWARD
VC~102,
VC-202,
REVERSE
VC-104,
vC-204
Thread record test tape SCOTCH 150 on the unit.
Place
the
RECORD
MODE,
EQ
and
BIAS
switch
to
NORMAL
position.
as in HIGH position.
$5
( O
Vei01_yn@ LEAS)
|
> FORWARD @
O-REVERSE VC103 »p»@
| VC104 @ 0 x @ SCREWDRIVER ADJUSTMENT
VC201 ypr@
e H
VC
202,94
o
1
HIGH
N ———a
VC 203 pS wt =O
Q | NORMAL.
VC 204 pp@ § x
RECORD MODE, EQ
and BIAS SW
Fig. 7-7 Bias Adjustment Locations
-Diagram—