Sony BVU-950 - Page 41

FOR
TRAINING
PURPOSES
ONLY
Section 2. DYNAMIC TRACKING BVU-920
-PRELIMINARY-
1C302
3
pin:
SUBJECT
TO
CHANGE
A voltage proportional to the changes in the bimorph is obtained at TP301, but the voltage waveform is
as shown at left during distortion suppression and SG drift adjustment. The voltage at TP301 after drift
adjustment is within +30mV.
C325 and C328, which are before IC306, are capacitors designed to hold the voltage. The output from
the strain gauges in the drum passes out via the slip ring and brush. If the brush contact is even
momentarily unsatisfactory during drum rotation, the strain gauge voltage will be incorrect and the DT
head will cause mistracking. Thus, this structure prevents the input voltage from changing rapidly.
RV305, R367-370:
Constitute a bias voltage adjustment circuit for changing the standard operation height of the bimorph.
During playback of standard tape, the RF is adjusted to maximum.
IC402: There isprotection of damage if an over-voltage is applied to the bimorph. This voltage limiter is de-
signed to prevent such voltages being applied. The limiter voltage is set by RV401.
IC401 and Q401-406:
A high-voltage amp for the bimorph drive. Gain is set at 48 times.
Distortion Drift
Suppression Adjustment
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oom
Stable
0.3sec
4-25