Sony TC-K890ES - Bias Consumption Current Adjustment; Bias and Recording Level (HX PRO ON) Adjustment; Metal Bias Adjustment

Bias Consumption Current Adjustment
Precautions:
Be sure to adjust bias consumption currents before adjust-
ing recording bias. After completion of adjusting bias
consumption currents, again adjust recording bias.
Condition:
HX PRO switch: ON
Procedure:
1. Set the semi-fixed resistances RV303 (L-CH) and RV403
(R-CH) for the adjustment of recording bias and RV554
at a mechanical center and set the equipment to recording
state without signals.
2. Adjust T301 (R-CH) and T401 (L-CH) so that the digital
voltmeter indicates a minimum value.
Digital —
voltmeter
B+(+8.5V)
Adjustable limits:
120mV or less
(When measured using CS-413 after completion of adjusting
the bias)
Bias and Recording Level (HX PRO ON) Adjustment
Conditions:
REC LEVEL knob: Specified recording position (see Page 3)
HX PRO switch: ON
Procedure:
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Simultaneous record/playback _ state
Line input
AF
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305Hz,
32mV(—27.8dB)
10KHz, 32mV(—27.8dB) Unrecorded tape
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Oscilloscope VTVM
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Line output
In order that the minimum output becomes the specified
output level:
(1) Adjust RV303 (R-CH) and RV403 (L-CH).
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(2) Adjust RV301 (R-CH) and RV403 (L-CH).
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| TC - K222ESA/K890ES
Adjustable limits:
(1) Difference of 10kHz level from 315Hz level: +0.3dB '34B
(2) Level of 315Hz: —27.5dB to —28.1dB
Bias Adjustment (HX PRO OFF)
Conditions:
REC LEVEL knob: Specified recording position (see Page 3)
HX PRO switch: OFF
Procedure:
1. Simultaneous record/playback _ state
305Hz, 32mV(—27.8dB)
AF _OSC 10KHz, 32mV(—27.8dB)
C3
10kQ
Line
input
Unrecorded
tape
O|
Attenuator
CS-222
Line output
2. Adjust RV302 (L-CH) and RV402 (R-CH) so that the
difference between playback outputs of 10kHz and 315Hz
becomes 0.2 + 0.3dB.
METAL bias Adjustment
Conditions:
REC LEVEL knob: Specified recording position (see page 3)
HX PRO switch: OFF
Procedure:
1. Simultaneous record/playback | state
305Hz, 32mV(—27.8dB)
endl
10KHz,
32mV(-27.8dB)
€3
10kQ
Line
input
Unrecorded
tape
O|
Attenuator
CS-413
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11,000
-
Line output
2. Adjust RV554 so that the difference of the playback
output of 10kHz R-CH from the playback output of
315Hz becomes +0.3dB.