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Level meter
Equipment:
+ VTVM
* Oscilloscope
* AF oscillator
+ ATT
Overall distortion
Equipment:
* Distortion meter
* AF oscillator
* ATT
* Oscilloscope
* Test tape---C-RA
(reference blank tape)
MEASUREMENT
& ADJUSTMENT
When standard recording level is supplied
1. Test equipment connection is shown in fig. 21.
Bw
AF Oscillator
LINE IN
LINE OUT
ATT
Record mode
Fig. 21
LINE IN (L-CH) jack.
. Adjust ATT until monitor level at LINE QUT (L-CH) jack becomes
0.42 V (—7 dB) and confirm that the level meter indicates
0 VU posi-
tion.
. If in the above condition, the level meter doesn't indicate OVU posi-
tion, change the "Connection points" of the amplifier pattern, and make
the adjustment.
circuit connection point © as shown in fig. 7.
the left meter. (See fig. 28 on page 17).
REMARKS
* Record mode
. Test equipment connection is shown in fig, 22.
co
ATT
6002 Record
mode
LINE OUT
law 3
oscillat
AF oscillator
Test tape
R/P head
Playback mode
Disto Higa?
meter
Fig. 22
Supply 1 kHz signal to LINE IN and adjust ATT so that output jevel
at LINE OUT indicates 0.42 V (—7dB).
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"
Test tape
Standard value:
|
Less than 3.0% (Normal)
|
Less than 3.5% (CrO2)
|
* LINE IN level contro!
* Bias selector ++++++++- LOW
| * Bias selector «+--+
*EQ selector -.+..+++
(for CrOz tape)
20uS
12
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