Technics RS-M228X - Page 4

RS-M228X
MEASUREMENT AND ADJUSTMENT METHODS
Tape
selector
(Tape
mode
switching)
(without
dbx
SYSTEM)
For measurement adjustment with test tapes without tape detection
holes switch tape modes as follows.
(For normal tape mode, just insert a normal tape into the cassette
holder.)
: Connection
* Metal tape mode setting: wire
Metal tape mode is obtained by disconnecting the 3 pin socket
from the 3 pin post [B] on the P.C.B. (Printed Circuit Board).
* CrO2 tape mode setting: GROUND
First, disconnect the 3 pin socket [D] in the same way as above.
Then, as illustrated in the figure right, connect the terminal-3 of
the 3 pin post to the ground with a connection wire.
es]
3 pin post-D)
Main P.C.B.
Tape Speed
Adjustment VR VR9 VR6 VR5 VR1 VR2
VR10
ey
elk
/ pee oe
| \
, VR301
a ea ee
a aoe ae
TP5.. >, TP3. “Jumper , TP301
8
A53f
|}
Ra7é
|)
|
x
9R330
‘SL
BEAK
RESET
TERMINAL
\
Fig. 1
NOTES: Keep good condition, set switches and controls in the following positions, unless otherwise specified
@ Make sure heads are clean. @ Input selector: Line
@ Make sure capstan and pressure roller are clean. ® Input level controls: Maximum
@ Judgeable room temperature: 20+5°C (68+9°F) © Output level control: Maximum
@ NR switch: OUT
Screw (A}
® Head position (The head adjusting plate 1s provided to adjust the tape Head Adjusting Plate
adjustment
touch
of
the
head
in
cue
or
review
mode.)
Capstan
Condition 1 Press the playback button and pause button — is
* Playback and pause mode 2 Measure the space between the pressure roller and the Rk
capstan
Standard value: 0.5+0.3mm
Space (adjustable?
If the measured value is not within the standard value,
untighten screw (A), and slide the head adjusting plate
in the direction of arrow (B) for adjustment
Fig. 2
© Head azimuth L-CH/R-CH output balance adjustment a ouT
adjustment 1. Make connections as shown in fig. 3. fossratplavacic est
Condition:
* Playback mode
Playback mode VTIVM Oscilloscope
Fig. 3
i Pressure Roller
ITEM MEASUREMENT & ADJUSTMENT
Equipment 2. Playback the 8kHz signa! from the test tape Record/playback head
*VTVM * Oscilloscope (QZZCFM)
* Test tape (azimuth) Adjust screw (B) in fig. 4 for maximum output L-CH \
+++ QZZCFM and R-CH levels
When the output levels of L-CH and R-CH are not at Screw (B)
maximum at the same time, readjust as follows Fig. 4
3. Turn the screw shown in fig 4 to find angles A and C
(points where peak output levels for left and right channels L-CH peak level
R-CH peak level
are obtained). Then. locate the angle B between angles A
r
and C. .e. a paint where L-CH and R-CH output levels sudan
come together at maximum. (Refer to figs. 4 and 5.) LEVEL
L-CH/R-CH phase adjustment
4. Make connections as shown in fig. 6.
5.
Playback
the
8kHz
signal
from
the
test
tape
(QZZCFM)
—_—
aE?
Adjust
screw
(B)
shown
in
fig.
3
so
that
pointers
of
the
two
A
BC
VTVMs
swing
to
maximum
and
a
waveform
as
illustrated
in
Fig.
5
fig. 6 Is obtained on the oscilloscope
Record/
VIVM
Oscilloscope
playback
head
)VIVM
|
ra
LH
ROS
A
=e
-
revs!) .
1 Eccapee seca Fig. 7
Playback LINE OUT Vertical Horizontal Fig, &
@ Tape speed Tape speed accuracy
Condition 1. Test equipment connection is shown in fig. 8.
+
Playback
mode
2.
Playback
test
tape
(QZZCWAT
3.000H2),
and
supply
Record/playback
head
LINE
OUT
«
Normal
tape
mode
playback
signal
to
frequency
counter
ee
eae
4
Equipment 3. Take measurement at middle section of tape | | oo
4. Measure this frequency. Test tape Playback mode ay Clectric counter
* Digital electronic counter
+ Test tape --- QZZCWAT 5. ha of 3,000HZz, determine value by following Fig. 8
f — 3.000
Af d ae eS 9
ape speed accuracy 3000 * 100 (%)
where, f = measured value
Standard value: +1.5% |
Adjustment method
1. Playback the test tape (middie)
2. Adjust so that frequency becomes 3,000 Hz
3. Tape speed adjustment VR shown in fig. 1
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:
f: —fe
Tape speed fluctuation = ——--— > Y
ape speed fluctuation 3000 * 100 (%)
f: = maximum value, f> = minimum value
Standard value: Less than 1.0%
®
Playback
frequency
Measurement
Playback
frequency
response
chart
response
1.
Test
equipment
connection
is
shown
in
Condition: fig. 3.
*
Playback
mode
2.
Place
UNIT
into
playback
mode
Aer
*
Normal
tape
mode
3.
Playback
the
frequency
response
test
tape
a6
* Output level control «-» MAX (QZZCFM). te
Equipment: 4. Measure output level at 315Hz. 125kHz, | ~2%8 rt
*VTVM — * Oscilloscope BkHz, 4kHz, 1kHz, 250Hz, 125Hz and | ~S8C
+ Test tape --- QZZCFM 63Hz and compare each output level with a - =n
the standard frequency 315Hz, at LINE (io.
OUT.
Fig. 9