Technics RS-M10 - Page 9

Overall frequency response
Equipment:
* VTVM
* AF oscillator
* ATT
* Test tape
(reference blank tape)
++ QZZCRA for Normal
«+ QZZCRX for CrOz
++ QZZCRY for FeCr
MEASUREMENT & ADJUSTMENT
. Supply 1kHz signal to LINE IN and adjust ATT so that output level at
LINE OUT indicates 0.39 V.
. Make recording.
. Playback and measure distortion factor of output signal.
. When the distortion factor does not satisfy the standard, check the
bias current. When the bias current is lower than standard, distor-
tion will increase.
Care should be exercised in the adjustment because the bias current
also has an influence on the overall frequency response. Refer to “The
overall frequency response” and “The bias current adjustment”.
Standard value:
Less than 3.0% (Normal position)
Less than 4.0% (CrO2, FeCr position)
Note:
Before measuring, and adjusting, make sure of the playback frequency
response (For the method of measurement, please refer to the playback
frequency response).
1.
2
SB:
4
Test equipment connection is shown in fig. 18.
. Load reference blank test tape and place UNIT into record mode.
Supply 1kHz signal from AF oscillator through ATT to LINE IN.
. Adjust ATT so that input level is —20dB below standard recording
evel (standard recording level — 24 dB).
. Record each frequency 50Hz, 100Hz, 200Hz, 1kHz, 2kHz, 4kHz,
8kHz and 10kHz (12 kHz for CrO2 and FeCr tape) at the same level.
. Playback and express in dB the difference between playback output
level of each frequency based on playback output level of 1kHz.
. Make sure that the measured value is within the range specified in the
overall frequency response chart.
“Overall frequency response chart (Normal)
2kHz
:
Fig. 21
. Set the tape selector to CrOz, FeCr position.
. Measure as same as manner above.
. Make sure that the measured value is within the range specified in the
overall frequency response chart for CrOz and FeCr tape below.
Overall frequency response chart (FeCr)
kHz ake orate
100Hz
REMARKS
* Record/playback mode
* INPUT level control
+» MAX