JVC RDT70BU
Service Manual

RD-T70BU/RD-T50LB

Flow of functional operation until TOC read
Check Point

Power ON

Play Key

Slider turns REST SW ON.

Confirm that the voltage at the pin5 of CN705-1 is "H"\"L"\"H".

Automatic tuning of TE offset

Check that the voltage at the

Laser ON

pin40 of IC701 is + 5V?

Detection of disc

Automatic tuning of Focus offset Confirm that the Focus error S-cuve signal at the pin32 of IC701 is approx.2Vp-p Confirm that the signal from pin24 IC701 is 0V as a accelerated pulse during approx.400ms.

Automatic measurement of Focus S-curve amplitude

Disc is rotated
Tracking error waveform at TOC reading pin 20 of IC702(TE)
Approx. 1.8V VREF

Approx.3sec

Focus servo ON (Tracking servo ON)

Automatic measurement of Tracking error amplitude
Tracking Disc to be servo braked to stop on states Disc states TOC reading to rotate finishes Automatic measurement of TE amplitude and automatic tuning of 500mv/div 2ms/div Fig.1 TE balance Tracking servo off states

Confirm the waveform of the Tracking error signal. at the pin 20 of IC702 (R705) (See Fig.1)

Automatic tuning of Tracking error balance

Automatic tuning of Focus error balance

Automatic tuning of Focus error gain

Automatic tuning of Tracking error gain

TOC reading

Confirm the eye-pattern at the lead of TP713

Play a disc

1-15