Technics RS-630USD

Playback frequency
response
Equipment:
*VTVM
* Oscilloscope
* Test tape---C-FH
MEASUREMENT & ADJUSTMENT
. Test equipment connection is as same as “Head azimuth adjustment”
but use the test tape (C-FH) instead of head azimuth tape (See fig.
1):
. Place UNIT into playback mode.
_ Play frequency response test tape (C-FH).
. Measure output level at 10KHz, 8kHz, 4kHz, 1kHz, 125Hz and 63Hz
and compare each output level 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
440 Hz
Fig. 15
. If measured value is not in standard, adjust VR1 (L-CH), VR2 (R-CH)
(See fig. 28 on page 14).
Playback gain
Equipment:
*VTVM
* Oscilloscope
* Test tape---C-FH
REMARKS
* Playback mode
. Test equipment connection is shown in fig. 11.
. Play standard recording level portion on test tape (C-FH 333Hz), and
using VTVM measure the output level at LINE OUT jack.
. Make measurement for both channels.
| Standard Value: 0.42V (—7dB)
Adjustment
1. If measured value is not standard, adjust VR3 (L-CH), VR4 (R-CH)
(See fig. 28 on page 14)
2. After adjustment, check “Playback frequency response” again.
* Playback mode
Playback S/N ratio
Equipment:
*VTVM
* Oscilloscope
* Test tape---C-FH
* Empty cassette
est equipment connection is shown in fig. 11.
jay standard recording level test tape (C-FH 333Hz) and read out-
ut level on VTVM.
efer to “Playback gain adjustment”.
ace empty cassette (which has been cut) and play again.
. Measure noise level at this time using VTVM, and determine ratio of
this level to test tape output signal voltage (333 Hz).
Standard Value: Greater than 43dB
An example calculation is shown below.
A: Es = playback output signal voltage of test tape (333 Hz)
B: En= playback output noise level
Es=0.42V (—7dB)
En = 3.0mV (—50dB)
i Sr ES 0.42V_
S/N ratio = En = 30mv = 140
20 logio 140 = 43dB
S/N ratio = Es(dB) — En(dB) = —7—(—50)=43dB
+ Playback mode