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4.3.2 Electrical adjustment
Item
Recording BIAS
• Forward or Reverse
adjustment
• Test tape
: AC-514 TYPE ll
: AC-225 TYPE l
• Output termina
Recording head
R/P playback
• Reference frequency
frequency
: 1kHz / 10kHz
response
(Reference: -20dB)
• Test tape
: AC-514 TYPE ll
• Input terminal
: OSC IN
4.3.3 Electrical response confirmation
Item
Recording bias
• Forward or Reverse
current
• Test tape
: TYPE ll (AC-514)
• Measurement terminal
: BIAS test point on printed
circuit board
Erase current (ref-
• Forward or Reverse
erence value)
• Rec condition
Test tape
: AC-514 TYPE ll
: AC-225 TYPE l
• Measurement terminal
Both side of Erase head
1-40 (No.MB161)
Condition
(1) Set the test tape(AC-514 TYPE ll and
AC-225 TYPE l), then make REC/
PAUSE condition.
(2) Connect 100Ω to recording head by se-
ries, then connect to VTVM for measure-
ment the current.
(3) After setting, start the recording by re-
lease the PAUSE, in this time bias cur-
rent adjust to next fig. by
and
4.0 µA (TYPE ll) and 4.20 µA (TYPE l).
(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 fre-
quency from oscillator.
(3) Playback the recorded position, 1kHz
and 10kHz output deviation should -1dB
2dB to readjust by
VR32
Condition
(1) Change BIAS1 and 2, confirm the fre-
quency 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.
(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.
Measurement method
VR31
for Lch
VR32
for Rch.
VR31
for Lch and
for Rch.
Measurement method
Adjustment
Ref. value
position
AC-225
VR31
: 4.20µA
AC-514
: 4.0µA
Output deviation
VR31
1kHz/10kHz
: -1dB ± 2dB
Adjustment
Ref. value
position
100 kHz ± 6 kHz
TYPE ll
: 120 mA
TYPE l
: 75 mA
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