Technics RS-676US - Page 13

MEASUREMENT & ADJUSTMENT
REMARKS
Bias Leak
Equipments:
* VTVM
* Oscilloscope
Bias Current
Equipments:
+ VTVM
* Oscilloscope
1. Test equipments connection is shown below (See AMP
circuit board on page 24).
R25(L-CH)
R26 (R-CH)
(VIVM) (Oscilloscope)
Fig. 18
2. Place UNIT into record mode.
3. Adjust trap coils L5 (L-CH), L6 (R-CH), so that measured
value become minimum (See adjustment parts location on
page 19).
4, Make adjustment for both channels.
1. Test equipments connection is shown below.
(VTVM) (Oscilloscope)
Fig. 19
. Place UNIT into record mode.
. Read voltage on VTVM and calculate bias current by follow-
ing formula.
Value read on VTVM (V)
Bias current (A) = 10 (OQ)
Standard Value: 0.17+0.05mA
. Adjust trimmer capacitors of VC301 (L-CH), and VC302
(R-CH) (See adjustment part location on page 19).
* Record Mode
* Record Level Control
«MAX.
* Record Mode
* Be sure the ground end of
the meter is connected
to the ground end of the
resistor.
* When bias current is
adjusted on one channel
only, note that bias
current on the other
channel may vary.
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