JVC CA-UXP55, Service Manual

Page: 22 / 42

1-22 (No.22036)
3.5 Electric adjustment
3.6 Electric characteristic confirmation
Item
Mesurement
condition
Mesurement
procedure
Standard
value
Adjustment
position
Recording BIAS adjustment
Recording reproduction
frequency characteristic
Forward or reverse
Test tape: AC-514 TYPE and
AC-225 TYPE
Measurement output terminal:
Recording and headphone terminal Standard frequency: 1kHz/10kHz
(Srandard: -20dB)
Test tape: AC-514 TYPE
Measurement input terminal: OSC IN
1.Test tape (AC-514 TYPE ,AC-225
TYPE )is installed, and makes to
recording/pose.
2.Connects in the head for the recording
and to connect 100 with the series and
to measure the current of the bias,
connects with VTVM.
3.The pose is released after sets and the
recording begins. It is adjusted that the
current of the bias reaches the following
value by VR31 for L side at this time and
VR32 for R side.
4.0 (TYPE )and4.20 (TYPE ) 1.Test tape (AC-514 TYPE )is installed,
and makes to recording/pose.
2.Records the recording's releasing the
pose, beginning, and repeating 1kHz
and 10kHz of a standard frequency from
the frequency transmitter.
3.VR31 for L side and VR32 for R side are
adjusted so that the recorded part may
be reproduced and there is a difference
between 1kHz and 10kHz in 1dB }2dB,
and the recording is repeated again.
AC-225: 4.20
AC-514: 4.0
Output difference
1kHz/10kHz:-1dB 2dB
VR31
Forward or reverse
Test tape: AC-514 TYPE
Measurement terminal:
BIAS TP on P.C.board Forward or reverse
State of recording
Test tape: AC-514 TYPE and
AC-225TYPE
Measurement terminal:
Erase head's both ends
Item
Mesurement
condition
Mesurement
procedure
Standard
value
Adjustment
position
Current of recording bias Deletion current (standard value)
1. It is confirmed that BIAS1 and 2 are
switched, and the frequency changes.
2.Test tape (AC-514 TYPE ) is installed,
and recording/makes to the pose.
3.It is confirmed that it is BIAS TP on the
substrate and the frequency is 100Hz
6kHz. 1.Test tape (AC-514 TYPE )is installed,
and makes to recording/pose.
2.The pose is released and after sets in
the state of the recording, 1W is
confirmed, and connects with the series,
and the deletion current is confirmed
from erase head's both ends to the
erase head.
100kHz 6kHz
TYPE : 120mA
TYPE : 75mA