Electrical Adjustment - JVC UX-H33 Manuel D'instructions

3.2.2 Electrical adjustment

Item Condition
Recording
Forward or Reverse
BIAS
Test tape
adjustment
:AC-514 TYPE
:AC-225 TYPE
Output terminal
Recording head
R/P Reference frequency
playback : 1kHz / 10kHz
frequency (Reference: -20dB)
response Test tape
: AC-514 TYPE
Input terminal
: OSC IN
3.2.3 Electrical response confirmation
Item Condition
Forward or Reverse
Recording
Test tape
bias
: TYPE
current
Measurement
terminal
: BIAS test point on
printed circuit board
Forward or Reverse
Erase
Rec condition
current
Test tape
(reference
: AC-514 TYPE
value)
: AC-225 TYPE
Measurement
terminal
: Both side of Erase
head
Measurement method
1.Set the test tape(AC-514 TYPE
AC-225 TYPE ), then make REC/PAUSE
condition.
2.Connect 100
then connect to VTVM for measurement the
current.
3.After setting, start the recording by release
the PAUSE, in this time bias current adjust
to next fig. by VR31 for Lch and VR32 for
Rch.
4.0 A (TYPE
1.Set the test tape (AC-514 TYPE ), then
make REC/PAUSE condition.
2.Release the PAUSE, then start recording
the 1kHz and 10kHz of reference frequency
from oscillator.
3.Playback the recorded position, 1kHz and
10kHz output deviation should -1dB
to readjust by VR31 for Lch and VR32 for
Rch.
Measurement method
1.Change BIAS1 and 2, confirm the frequency
should be change.
(AC-514)
2.Set the test tape (AC-514 TYPE ), then
make REC/PAUSE condition.
3.Confirm the frequency should 100Hz
at BIAS test point on printed circuit board.
1.Set the test tape (AC-514 TYPE
AC-225 TYPE
condition.
2.Release the PAUSE to REC condition,
connect 1W to ERASE head by series, then
confirm the erase current at both side of
erase head.
and
to recording head by series,
) and 4.20 A (TYPE ).
2dB
6kHz
and
), then make REC/PAUSE
Adjustment
Ref.value
position
VR31
AC-225
:4.20 A
AC-514
:4.0 A
Output
VR31
deviation
1kHz/10kHz
:-1dB 2dB
Adjustment
Ref.value
position
100 kHz
6 kHz
TYPE
: 120 mA
TYPE
: 75 mA
(No.22044)1-21
UX-H33