Technics SL-P250 - Page 43

SL-P250
(TOC Read Operation-PLAY Operation)
Open/Close switch
pressed.
(Operation Sequence Just After Power On)
Power On
(no disc loaded)
No
ARF signal turned
into SRF signal?
@ DSL circuit failure:
9
Focus
servo
locked?
©
1C102
No| @ FO error amp. failure:
@1C101, 104
@ Power supply failure:
¢ Voltage regulator IC (IC11,
13, 104, Q11, 12)
¢ IC protector (IC1, 2, ICP11,
12)
@ Microprocessor failure:
© 1C601, 401
@ Microprocessor failure
(1C401, 601)
@ Operation key switch failure
@ Tray open switch failure
— SRF signal check method —
Has the tr.
‘ay
opened
poe
that
the
SRF
signal
is
present
at
and stopped?
FL display came on? pin 19 of 1C102
Yes Yes
Yes
Load a disc and press
the Open/Close switch.
@ Microprocessor failure:
© 10401
@ Control system failure:
¢1C101, 102
@ TR error amp. failure:
10101, 102, 103
@ Pickup failure:
¢ Tracking coil
SRF signal
synchronized
with PCK?
No No
@ PLL circuit failure:
?
Tracking
servo
locked?
°
10301,
102
— Synchronization check method —
Trigger the oscilloscope with the RF
signal (TJ101) and observe the PCK at
Yes | pin 20 of IC102.
If phase synchronization is establish-
ed, the FPC at IC301’s pin 78 will be
regulated to approx. 2.5V.
Yes
@ Microprocessor failure
(1C401)
@ Operation key switch failure
@ Tray close switch failure
Has the tray closed ~_No
and stopped?
@ Microprocessor failure:
© 1C401
@ Traverse amp. failure:
©1C101, 102, 103
traverse coil
CLV servo
entered the Phase
Compare mode?
No} @ CLV circuit failure:
e 10301
No
Traverse servo
operation normal?
Yes
Tray closed?
Does optical
pickup move toward
inner track?
@ Microprocessor failure:
¢ 1C401, 601
@ Loading motor driver failure:
© Q401, 402, 1C402, motor
@ Close switch failure
@ Pickup failure:
e Laser diode
No] @ Control system failure:
©1C101, Q101
@ Microprocessor failure:
Laser diode came on?
10401
— Laser diode turn-on check method —
Remove the disc then close the tray,
and the laser diode will come on for
approx. 5 sec.
Yes
@ Traverse control system
failure:
¢1C102, traverse coil
°1C103, potentiometer
@ Microprocessor failure:
© 1C401
@ Control system failure:
¢1C101, 102
@ FO error amp. failure:
10101, 102, 103
@ Pickup failure:
Does focus lens
make vertical
movements?
Yes
entered the
Yes
Has DSL circuit
Normal mode?
— DSLcircuit Normal mode check method —
— Phase Compare mode check method —
Verify that the CLVS at pin 77 of 1C301
is set to High.
— Traverse servo checking method —
e Track skip occurs at inervals of a few
seconds during play.
¢ Pickup moves back and forth
between the innermost and
outermost tracks.
e Pickup moves to the innermost or
outermost track and stops there.
NO} @ Microprocessor failure:
°1C401
Yes
‘EFM signal and
PCK clock outputs
present?
No
@ PLL circuit failure:
©1C102
— EFM and PCK check method —
Check the waveform of EF M at 1C102’s
pin 21 and that of PCK at 1C102’s pin
° Verify that 1C102’s pin 31 is set to
20.
Low.
Yes
@ DF/DAC circu it failure:
¢ Focus coil
RF signal
amplitude regulated
at the output of
AGC circuit?
¢ 1C801
@ Low-pass filter circuit
failure:
° 1C803, 804
Audio signal
output present?
Yes
NO} @ AGC circuit failure:
°1C101
Stops after making focus pull-
in operation for approx. 5 sec.
@ Microprocessor failure:
© 1C401
No| @ T.T. drive system failure:
¢ 10301, 402, Q351
© Q403, 404
Spindle motor
Spindle motor
started rotation?
Yes
Yes
— AGC circuit check method —
Verify that the ARF signal amplitude at
pin 35 of 1C101 is 0.5Vp-p.
¢ IC805, 806
Play operation