Technics RS-615US-D - Page 10

Wow and flutter
Equipment:
* Wow meter
* Test tape --- C-WAT
MEASUREMENT & ADJUSTMENT
1. Test equipment connection is shown below.
LINE OUT
Playback mode Wow meter
Fig. 16
Test tape
. Use wow test tape (3,000Hz) and measure its playback signal on
wow meter.
. Wow and flutter is expressed in percentage and that measurement an
be weighted by JIS network (WRMS).
. Measure at middle section of test tape.
| Standard value: 0.10% (WRMS)
REMARKS
* Playback mode
Playback frequency
response
Equipment:
*VTVM
* Oscilloscope
* Test tape---C-FH
. Test equipment connection is as same as “Head azimuth adjustment”
but use the test tape (C-FH) instead of head azimuth tape (See fig.
12).
. Place UNIT into playback mode.
. Play frequency response test tape (C-FH).
. Measure output level at 1OkHz, 8kHz, 4kHz, 1kHz, 125Hz and 63Hz
and compare output leve! with standard frequency 333Hz, at LINE
OUT.
. Make measurement for both channels.
. Make sure that the measured value is within the range specified in the
frequency response chart.
Playback frequency response chart
63Hz 125Hz 250Hz | 430Hz
333Hz
Fig. 17
Playback frequency
response
* Playback mode
Adjustment
1. If the measured value decreases at high frequency range, as shown in
fig. 18, P.C.B. connection points (B) should be shorted to increase at
high frequency range (See fig. 22 on page 11).
+ 2.5dB
+ 2dB
~ 2B
2.5¢B
333Hz 430Hz 6.3kHz — 10kHz
Fig. 18
The corrected value
4kHz | 6kHz kHz
| about about about
+0.2dB +0.8dB ; +1.0dB
L a
* Playback mode