Technics RS-273US - Page 6

ITEM
MEASUREMENT & ADJUSTMENT REMARKS
Playback Frequency
Response
Equipment:
x VTVM
*« Oscilloscope
* Test Tape...C-FH
Playback Gain
Equipment:
* VTVM
* Oscilloscope
* Test Tape...C-FH
. Test equipment connection is as same as for “Head Azi-
muth Adjustment”, but use the tast tape (C-FH) instead of
head azimuth tape (See fig. 7).
. Set tape selector to normal! position.
. Play frequency response test tape (C-FH).
. Measure output leve! (at LOKHz, 8kKHz, 4kHz, 1 kHz, 125
Hz and 63Hz) and compare output level with standard
frequency 333Hz, at LINE OUT jack.
. 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
+5 dB
333 Hz
+2 dB
0 dB
—1dB
—2 dB
63 Hz 125 Hz —3 dB
1 NO eed
VkHz 4kHz 8KHZ IQ kHz
Fig. 13
if measured value is not in standard, adjust VR1 (L-CH),
VR2 (R-CH) shown in fig. 26 on page 12.
If the frequency characteristic becomes lower than the
standard value, especially in high frequency range (8 kHz,
10 kHz), short the circuits @(L-CH), ®(R-CH) on the copper
foil of the PCB shown on page 16, then readjust the cara-
cterristics by using procedure described above.
Test equioment connection is shown in fig. 7.
. Play standard recording level portion on test tape (C-FH
333Hz) and, using VTVM, measure the output ievel at
LINE OUT jack.
. Make measurement for both channels.
Standard Value: 0.5 V (—6 dB) |
Adjustment
I.
2.
If measured value is not standard, adjust VR3 (L-CH), VR4
(R-CH).
After adjustment, check “Playback Frequency Response”
again.
* Playback Mode
* Playback Mode
* Location of VR3 and VR4
are shown in fig. 26.
Playback S/N Ratio
Equipment:
* VTVM
* Oscilloscope
* Test Tape...C-FH
* Empty Cassette
. Test equipment connection is shown in fig. 7.
. Play standard recording level test tape (C-FH 333Hz), and
measure the output level.
Refer to “Playback Gain Adjustment”.
. Place empty cassette (which has been cut) and play again.
Measure noise level at this time using VTVM, and deter-
mine ratio of this level to test tape output signal voltage
(333Hz).
Standard Value: Greater than 43dB
* Playback Mode