Technics RS-M7 Service Manual

RS-M7
MEASUREMENT & ADJUSTMENT
5. Take measurement at middle section of tape.
Standard value: 1.5%
Adjustment method
1. Playback the test tape (middle).
2. Adjust so that frequency becomes 3,000 Hz.
3. Tape speed adjustment VR shown in fig. 21.
Tape speed fluctuation
Make
measurements
in
same
manner
as
above
(beginning,
middle
and
end
of
tape),
and
determine
the
difference
between
maximum
and
minimum
values
and
calculate
as
follows:
fit ;
3.000 X 100 (%)
f1=maximum value, f2=minimum value
Standard value: 1%
1. Test equipment connection is shown in fig. 8.
2. Playback standard recording level portion on test tape (QZZCFM 315Hz), and using VTVM measure
the output level at LINE OUT jack.
3. Make measurement for both channels.
Standard value: 0.39V
Adjustment
1. If measured value is not standard, adjust VR3 (L-CH), VR4 (R-CH) (See fig. 21 on page 5).
2. After adjustment, check “Playback frequency response” again.
Tape
speed
fluctuation
=
Playback gain
Condition:
* Playback mode
Equipment :
*VTVM
* Oscilloscope
« Test tape --- QZZCFM
Bias
current
.
Test
equipment
connection
is
shown
in
fig.
11.
&
>
R/P
head
Condition: 2. Place UNIT into record mode, and tape selector to normal
* Record mode position. |
* When bias current is 3. Read voltage on VTVM and calculate bias current by following
adjusted
on
one-channel
formula:
;
Value read on VTVM (V) Fig. 11
only, note that bias current
on the other channel may
vary.
* When L5 or L6 ts the
replaced, preset core
position to bottom side of
coill and then readjust
optimum bias current.
Bias current (A) = 10)
Standard
value:
285A
(Normal
position),
340uA
(Fe-Cr
position),
380A
(CrO2
position)
4. Adjust L5 (L-CH) and L6 (R-CH) (See fig. 21 on page 5).
Equipment:
*VIVM_ * Oscilloscope
Erase head
Erase current . Connect 1Q resistor between the ground side terminal of
Condition: erase head ground lead wire removed (See fig. 13).
* Record mode 2. Connect VTVM to both ends of 12 resistor. Recording.
* 3. Place UNIT into record mode, and measure voltage across the ie
Equipment: ;
* VTVM 1Q resistor. VTVM Oscilloscope
j 4 Determine erase current with the following formula: Fig. 12
* Oscilloscope ,
Voltage across both ends of 12 resistor Erase hea
* Resistor (1) Erase current (A) =
1 (Q)
1(9)
Fig. 13
Standard
value:
More
than
40mA
(Normal
position),
More
than
45mA
(Fe-Cr
position),
More
than
55mA
(CrQz
position)

Technics RS-M7 Specifications

General

Brand	Technics
Model	RS-M7
Category	Cassette Player
Language	English