JVC HX-Z9, Service Manual

Page: 36 / 77

1-36 (No.22066)
4.4.1 Electrical adjustment
4.4.2 Electrical response confirmation
If change the CD mechanism or printed circuit board, should done the initialize operation for write the mechanism position to E2PROM.
Initialize operation is done to next operation.
Set to standby condition
Press together the cassette Reverse key and clock key of main body.
Keep this condition, then power switch to ON.
Initialize operation is automatically to start and stop.
Complete the initialize operation.
Initialize operation is release by power switch to OFF.
Item Condition Measurement method Ref. value
Adjustment
position
Recording BIAS
adjustment • Forward or Reverse
• Test tape
: AC-514 TYPE ll
: AC-225 TYPE l
• Output terminal
Recording head
(1) Set the test tape(AC-514 TYPE ll and AC-225
TYPE l), then make REC/PAUSE condition.
(2) Connect 100
Ω
to recording head by series,
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
µ
A (TYPE ll) and 4.20
µ
A (TYPE l).
AC-225
: 4.20
µ
A
AC-514
: 4.0
µ
A
VR31
R/P playback
frequency
response • Reference frequency
: 1kHz / 10kHz
(Reference: -20dB)
• Test tape
: AC-514 TYPE ll
• Input terminal
: OSC IN
(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 2dB to
readjust by VR31 for Lch and VR32 for Rch.
Output deviation
1kHz/10kHz
: -1dB ± 2dB VR31
Item Condition Measurement method Ref. value
Adjustment po-
sition
Recording bias
current • Forward or Reverse
• Test tape
: TYPE ll (AC-514)
• Measurement
terminal
: BIAS test point on
printed circuit board
(1) Change BIAS1 and 2, confirm the frequency
should be change.
(2) Set the test tape (AC-514 TYPE ll), then make
REC/PAUSE condition.
(3) Confirm the frequency should 100Hz ± 6kHz at
BIAS test point on printed circuit board.
100 kHz ± 6 kHz
Erase current
(reference
value) • Forward or Reverse
• Rec condition
Test tape
: AC-514 TYPE ll
: AC-225 TYPE l
• Measurement
terminal
Both side of Erase
head
(1) Set the test tape (AC-514 TYPE ll and AC-225
TYPE l), then make REC/PAUSE 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.
TYPE ll
: 120 mA
TYPE l
: 75 mA