Technics QUARTZ SL-MA1 - Page 14

ON-timing of
D404 and D405 ,, |
® |. ae Lf
(D404)
H
|
|
|
oo oe
i |
Input of Ic401 & 7
(D405)
pin i | t 1 i
No record | | | | | |
L
q = 1
17 cm record || | |
L
H
30 cm record
No record is present........ The light of 2 LED’s is input.
17 cm record is present...... The light of only outer periphery
LED (D405) is input.
30 cm record is present...... No light of LED is input.
The microcomputer detects the sizes of record by the operations
mentioned above.
L
3. Arm position detection circuit
The rest position, 30 cm record, 17 cm record lead-in position and return area are detected by the slit plate and optical
detection element located under the tonearm, and the input is entered into the microcomputer.
1c 401
The optical detection element (PC501) is equipped with 2
detection elements @ and ©.
When the tonearm is on the rest, the slit plate is in the
Position as shown on the right, then both detection
elements @) and are ‘‘on’’, and microcomputer pins
@ and @) are at “H”.
At the outer periphery (lead-in position) of 30 cm record,
the slit plate is in the position as shown on the right, the
detection element @) is “off” and is on’, then micro-
computer pin @) goes ‘“’L” and pin @) , “H”.
Also, for the outer periphery position of 17 cm record, the
states are the same as above.
In the range of tonearm return, the slit plate is in the
position shown on the right, the detection element @) is
“on” and ©@®) is “off, then microcomputer pin @) goes
“H” and pin @), “L”.
In the other modes (lead-in, return operation, play modes),
both deteciton elements @ and are “‘off’’, then micro-
computer pins @) and @f) are at “L”.
Optical detection
element (PC501)
Rest position
detection
Slit plate
30 cm record
position detection
Return area
detection
17 cm record
position detection
Slit plate
PC501
Slit plate
Rest position
17 cm record position
Slit plate
Return area