Technics RS-M10 - Page 10

MEASUREMENT & ADJUSTMENT REMARKS
Overall frequency response chart (CrO2)
2kHz 4kHZ
{ {
Overall frequency response | Adjustment 1— Using bias current
adjustment 1. When the frequency response between the middle and high-frequency
(As a standard for adjustment) range becomes higher than the standard value, as shown by the solid
line in fig. 24, increase the bias current by turning L5 (L-CH), L6 (R-
CH).
. When it becomes lower, as shown by dotted line, reduce the bias cur-
rent by turning L5 (L-CH), L6 (R-CH).
Note:
For the method of bias current measurement, refer to “Bias current
adjustment” on page 6.
Fig. 24
Adjustment 2—Using the peaking coil for recording
equalization
When the frequency response is flat in the middle-frequency range and
makes a sharp rise or drop in the high-frequency range, as shown in fig.
25, adjust by turning the peaking coil L3 (L-CH), 4 (R-CH) for normal
tape recording equalization.
2kMe Skee 1OkHr 1 KH?
Fig. 25
Dolby
NR
circuit
.
Place
UNIT
into
record
mode,
set
the
Dolby
NR
switch
to
OUT
posi-
|
*
Record
mode
Equipment:
tion
and
supply
to
LINE
IN to
obtain
—34.5dB
at
TP3
(L-CH),
TP4
|
*
INPUT
level
control
* VTVM (R-CH) (frequency 5kHz). + MAX
* AF oscillator . Confirm that the value at IN position is 8(42.5)dB greater than the
* ATT value at OUT position of Dolby NR switch.
* Oscilloscope
Overall
S/N
ratio
.
Test
equipment
connection
is
shown
in
fig.
18.
*
Record/playback
node
Equipment:
.
Supply
1kHz
signal
to
LINE
IN
and
adjust
ATT
so
that
output
level
at
|
*
INPUT
level
contrd
*
VTVM
LINE
OUT
indicates
0.39
V.
-
+
MAX
*
AF
oscillator
.
Make
recording.
*
Erase
the
tape
wit)
a
bulk
*
ATT
.
Make
another
recording
without
supplying
signal
(disconnect
input
plug
tape
eraser.
*
Oscilloscope
to
LINE
IN),
«
Test
tape
.
Rewind
to
recorded
part
and
playback.
(reference
blank
tape)
.
Measure
output
signal
level
and
no
signal
level
(noise),
and
determine
.-
QZZCRA
the
ratio
in
decibels
(dB).
.
The
value
is
difference
between
“Playback
S/N
and
overall
S/N’,
but
for
decibel
calculation
refer to
“Playback
S/N
measurement”
on
page
5.
Standard value:
Greater than 43dB (without NAB filter)