Flow Of Functional Operation Until Toc Read - JVC UX-T77 Service Manual

UX-T77

Flow of functional operation until TOC read

Power ON
Tracking error waveform at TOC reading
Approx.3sec
pin 25 of
IC601(TE)
Approx
1.8V
VREF
Tracking
servo
off status
Disc status
to rotate
Automatic measurement
of TE amplitude and
automatic tuning of
TE balance
1-20
Slider turns REST
Power Key
Automatic tuning
of TE offset
Detection of disc
Automatic tuning of
Automatic measurement of
Focus A-curve amplitude
Automatic measurement of
Tracking error amplitude
Tracking
Disc to be
servo
braked to stop
Automatic tuning of
on status
TOC reading
Tracking error balance
finishes
500mv/div
2ms/div Fig.1
SW ON.
Laser ON
Focus offset
Disc is rotated
Focus servo ON
(Tracking servo ON)
Automatic tuning of
Focus error balance
Automatic tuning of
Focus error gain
Automatic tuning of
Tracking error gain
TOC reading
Play a disc
Check Point
Check that the voltage at the pin17
of CN604 is 0V (a moment)?
Check that the voltage at the
pin3 of IC601 + side is + 5V?
Confirm that the Focus error
S-cuve signal at the pin27 of
IC601 is approx.2Vp-p
Confirm that the signal from
pin24 IC603 is 0V as a
accelerated pulse during
approx.400ms.
Confirm the waveform of
the Tracking error signal
at the pin25 of IC601 (R612)
(See fig-1)
Confirm the eys-pattern
at the lead of TP1