Technics RS-D400 Serviceanleitung Seite 10

RS.D400
Set switches and controls in the following positions, unless otherwise specified.
NOTES:
• Make sure heads are clean
• Make sure capstan and pinch roller are clean
• Judgeable room temperature 20±500
• NR switch: OUT
O Head azimuth Condition:
adjustment • Playback mode
• Normal tape mode
L•CH/R-CH output balance adjustment
1. Make connections as shown in fig. 2.
2. Playback the 8kHz signal from the test tape (QZZCFM).
Adjust screw (B) in fig. 3 for maximum output L-CH and R•CH levels.
When the output levels of L-CH and R-CH are not at maximum
same point adjust as follows.
3. Turn screw (B) shown in fig. 3 to find angles A and C (points where
peak output levels for left and right channels are obtained).
locate angle B between angles A and C, i.e., point where L-CH and
RCH outputs are balanced. (Refer to figs. 3 and 4.)
phase adjustment
4. Make connections as shown in fig. 5.
5. Playback the 8kHz signal from the test tape (QZZCFM).
Adjust screw (B) shown in fig. 3 so that pointers
swing to maximum and a lissajous waveform
obtained on the oscilloscope.
EVM
Record/
playback head
o
p.ch—
Playback
LINE our
mode
Fig.
@ Tape speed Condition:
• Playback mode
Tape speed accuracy
1. Test equipment connection is shown in fig. 7.
2. Playback test tape (QZZCWAT 3,000Hz), and supply playback
to the digital frequency counter.
3. Measure this frequency.
On the basis of 3,000Hz, determine value by following
4.
f-3,OOO
Tape speed accuracy = x
3,000
5. Take measurement at middle section of tape.
Standard value: ±1.5%
6. If measured value is not within the standard value, adjust it by using the tape speed adjustment
fig. 1.
Note: Please use non metal type screwdriver
Tape speed fluctuation
Make measurements in same manner as above (beginning,
difference between maximum and minimum values
ft-f2
Tape speed fluctuation
= 3,000
Standard value: Less than 1%
• Tape selector: Normal
• Input selector: Line in
(68±90 F) • Input level controls: Maximum
• Balance control: Center
Equipment:
• EVM (Electronic Voltmeter)
• Oscilloscope
• Test tape (azimuth). ..QZZCFM
LINE OUT
Record/
playback nead
EVM
Playbac* mode
Fig. 2
at the
RecorC/p4ayback
c
neat
B
Then,
Sc:e•
Fig. 3
L•ch peak level
R-ch peak •vel
OUTPU
LEVEL
of the two EVMs
as illustrated in fig. 6 is
Fig. 4
Oscilloscope
EVM
O
Vert•cal Horizontal
Fig. 6
5
Equipment:
• Digital frequency counter
• Test tape...QZZCWAT
Record/ playback LINE OUT
signal
Digital trequency counter
est
formula: Fig. 7
where, f = measured value
VR shown in
when you adjust tape speed accuracy on this unit.
middle and end of tape), and determine
and calculate as follows:
f1 = maximum value, fa = minimum value
Playback frequency
response
1. Test equipment connection
2. Playback the frequency
(QZZCFM).
Measure output level at 315Hz, 12.5kHz, 8kHz, 4kHz, 1kHz,
3.
250Hz, 125Hz and 63 Hz, and compare
with the standard frequency
4. Make measurements
5. Make sure that the measured values are within the range
specified in the frequency response chart. (Shown in fig. 8).
Oscilloscope
Playback gain
1. Test equipment connection
2. Playback standard recording level portion on test tape (QZZCFM 315Hz) and, using EVM, measure the
output level at test points Pin 7 of IC5 (L-CH), IC6 (RCH).
3. Make measurements
Standard value: 0.28V [O.4V±1dB: at LINE OUT jackl
ANGLE
Adjustment
1. If the measured value is not within the standard, adjust VRI (L-CH) or VR2 (R-CH) (See fig. 1).
2. After adjustment, check "Playback frequency response" again.
@ Erase current
1. Test equipment connection
2. Place UNIT into metal tape mode.
3. Press the record and pause buttons.
Read voltage on EVM and calculate
4.
formula:
Erase current (A) =
Standard value: 155±15mA
5. If the measured value is not within the standard value adjust it by
following the adjustment
Adjustment
• If the erase current is more than 170mA, cut the jumper wire (See fig. 1).
Overall frequency
response
the
Note:
Before measuring and
response make sure of the playback
the method of measurement,
auency response).
Condition: Equipment:
• Playback mode
• EVM (Electronic
• Normal tape mode
• Oscilloscope
• Test tape...QZZCFM
is shown in fig. 2.
Playback frequency
response portion of test tape
each output level
315Hz, at LINE OUT.
for both channels.
Condition: Equipment:
• Playback mode
• EVM (Electronic
• Normal tape mode
• Oscilloscope
• Test tape...QZZCFM
is shown in fig. 2.
for both channels.
Condition: Equipment:
• Record mode
• EVM (Electronic
• Metal tape mode • Oscilloscope
is shown in fig. 9.
RecorC
erase current by following
Voltage across resistor R84
(Metal)
instructions.
Condition: Equipment:
• Record/playback mode • EVM (Electronic
Voltmeter)
• Normal tape mode
• Cr02 tape mode
• AF oscillator
• Metal tape mode
• Oscilloscope
• Input level controls...MAX
• Resistor (600Q
adjusting, the overall frequency
frequency response (For
please refer to the playback fre-
Voltmeter)
response chart
- •3dB
Od8
12.500
Fig. 8
Voltmeter)
Voltmeter)
Erase head
TPS
mode
6)
R84 (IQ)
EVM Osc.lioscope
Fig. 9
• Test tape
(reference blank tape)
QZZCRA for Normal
QZZCRX for cr02
...QZZCRZ for Metal