Hitachi HT-L55 Serviceanleitung Seite 19

A\
F\
A\
Pin
No. Pin
Symbol
Use
@
D8 Platter rotation contfol
srgnal output
pin to lc (HA12032)
Normally, this
pin
is at LOW
level.
When the
platter
starts rotating,
a
HIGH level siqnal
is
output
@
D9 Platter speed control
signal
output pin to
lC (HA1
2032)
When the
platter
speed is 33-
1
/3
(45) rpm, a HIGH (LOW) level
siqnal
is
ourpur
@
I
úì
D10
I
D15
Vacanî
@ Vdisp
Microcomputer
MOS
power
supply pin
Connected to VDD
pin @ (cND).
@ Reset
lnitial reset pin.
A
HIGH level signal is input
when power
is
switched
ON
to
carry
out
initial reset.
Normally, a LOW level signal is
input
@ VBB
Memory back-up power supply pin.
As the memory back-up sysîem is not employed,
îhis is connected to
VDD
pin
@
(GND)
@ VDD
Power supply
pin.
(Connected
îo
GND)
@
íÒ
osc
1
osc2
Ceramic oscillator
input pin
Used as a reference of
microcomputer operation (4O0
kz)
@
lesl
Microcomputer tesî pin-
As
this
feature is noî used, thìs
is
connected to Vss pin
@
@
Vss
A voltage
of +
1
OV is
applied
@
RO0 Arm
START/CUT
swirch inpuî pin
When a HIGH level signal is input with the tonearm on the
rest,
the
unit is set to îhe start mode
When the tonearm
is in other than
the rest position, the unit is set to the
cut
mode
@ RO1
Arm
OUT
switch input pin.
When a
HIGH
level signal is input,
the
unit is set to the
ouî
mode
@
RO2
Arm
UP/DOWN switch input pin
When a HIGH level signal is input, the unit is set to
DOWN (UP) mode with the ronearm set to the
UP
(DOWN) poinî
@
RO3 Arm
in swiîch input pin.
When a HIGH level signal
is
inpul, the
unit is set to
the
lN mode
@
R10
Repeat swiîch inpuî pin
When a HIGH
level
signal is input,
îhe unit set to lhe repeat mode.
When the uniî has already been set to the
repeat mode, the repeat mode will
be released
@
R'l
1
Speed
switch inpuî pin.
Wheri a
HIGH
level signal
is ìnput,
the
spéed
is
changed from 33 1/3
rpm
to 45
rpm
or
vice versa
@
Rl2
Vacanî
@
R13
Vacant
@
INTO Tonearm position detecîion input
pin.
The tonearm posiîion from the rest
position
is
detected
by
counting
the
light pulses
€D
INTI
Dusî cover
swiîch input pin.
When a HIGH
level signal is input, the
unit is set to the
dust
cover open
mode
When a LOW
level signal is input, the
unit is set to the
dust
cover close
mode
@
R20
Repeat
LED
output
pin.
A
HIGH level signal
is
output to
lighî the
repeaî
LED
@
R21 45
rpm
LED
output pin
A
HIGH
level
signal
is
output îo
lighî the
45
rpm
LED
@
R22
33-1
/3
rpm
LED
output pin.
A
HIGH
level signal
is ourpur
to
light the
33-1/3
rpm LED
@
R23
Vacanî
@
@
@
@
830
R31
R32
R33
Arm motor
drive
ouîput pin
Controls the movement of tonearm.
Output pin No
Tonearm movement
@ @ @
@
H
L
L L Stop
H H
H H
Moved inward
L
H L L Moved outward.
H L
H L
DuriÀg playback.
@
DO Record
size
light pulse input pin
When a
HIGH
level signal is input, record size
detection
is carried out
(}
D1
Rest position detection
input
pin
.
When
a
HIGH level signal
is
input, the tonearm is
in
the rest
position
@
D2
Turntable lock
detection inpuî pin.
When a LOW
level signal is input
the
plaîter
is
rotating
at constant speed.
/\
-17-