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ITEM
MEASUREMENT & ADJUSTMENT
REMARKS
*« Record mode
* When bias current Is
adjusted on one channel
only, note that bias current
on the other channel may
vary.
Bias current
1. Test equipment connection is shown below.
Equipment:
*VTVM
* Oscilloscope
TP (L-CH)
o TP2 (R-CH)
VIVM
Oscilloscope
Fig. 17
Place UNIT into record mode, and bias selector to "LOW".
3. Read voltage on VTVM and calculate bias current by following for-
mula:
~
Value read on VTVM (V)
10 (Q)
Bias current (A) =
Standard value:
175A (LOW position)
180+20uA (MED position)
235+30uA (HIGH position)
L
=
4. Adjust VR17 (L-CH) and VR18 (R-CH) (See adjustment part location
on page 10).
1. Test equipment connection is shown below.
« Record mode
* Bias selector --- LOW
Erase current
Equipment:
«VTVM
* Oscilloscope
Erase head
Record mode
VTVM
Oscilloscope
Fig. 18
2. Place UNIT into record mode and set the bias selector to LOW posi-
tion.
3. Read voltage on VTVM and calculate erase current by following for-
mula:
Value read on VTVM (V)
1 (Q)
Erase current (A) =
Standard value:
More than 40mA (LOW position)
More than 45mA (MED position)
More than 55mA (HIGH position)
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