Sony S530D manual Focus Drive, Focus Search Communications, System Control IC202 to Servo IC701

Focus Drive

Servo IC701 outputs two square waves from pins 80 and 85 as long as the set is powered. The reference square wave comes from pin 80 and is fixed at 50% duty cycle. When the duty cycle of pin 85’s waveform changes, the focus coil receives current.

The following waveforms were taken during focus search. Note that the falling edge of the reference waveform (ch 2) is always in line with the drive signal (ch 3) from pin 85.

P M 3 3 9 4 , F L U K E & P H I L I P S

ch2: freq= 79 . 4kHz

ch2

ch3

2

T

3

CH2!2 . 00 V=

CH3!2 . 00 V= ALT MTB2 . 00us - 1 . 16dv ch3 -

Focus Search Waveforms

	Name	Location	Voltage/div
Channel 2	FCD -	IC701/pin 80	2Vp-p
Channel 3	FCD +	IC701/pin 85	2Vp-p
Time base		2usec/div.

This second group of waveforms compares the input and output of the driver IC801 during playback. When there is a change to the duty cycle of pin 9’s waveform, there is a differential voltage applied to the focus coil.

P M 3 3 9 4 , F L U K E & P H I L I P S

ch1: pkpk= 3 . 80 V

ch1

ch1: freq= 79 . 4kHz

ch2

1

ch3

ch4T

2

3

CH1!2 . 00 V=

CH2!2 . 00 V=

4

CH3!1 . 00 V~

CH4!1 . 00 V~ ALT MTB5 . 00us - 0 . 94dv ch2+

57

Focus Driver IC801 Input/Output

	Name	Location	Voltage/div
Channel 1	FCD -	IC701/pin 80	2Vp-p
Channel 2	FCD +	IC701/pin 85	2Vp-p
Channel 3	+ DO 1	CN003/pin 12	1Vp-p AC coupled
Channel 4	- DO 1	CN003/pin 13	1Vp-p AC coupled
Time base		5usec/div.

Driver IC801 supplies the current to the focus coil within the optical base assembly. The spring suspended focus coil is attached to the lens posi- tioned next to a stationary magnet. The lens is moved when current is applied to the coil. Lens movement changes the laser’s focal point.

Focus Search Communications

System Control IC202 to Servo IC701

During focus search, bi-directional communications take place between IC202 and IC701. Since the number of output ports IC202 has is limited, HGA IC601 is used as an expansion port to control the flow of bi-direc- tional information to and from destination ICs such as IC701. All three ICs share a common address and data bus. The information placed on the bus is time-shared by each IC. The time is controlled by System Control IC202.

System Control IC202 to HGA IC701

IC202 cannot communicate with IC701 directly to control servo opera- tions. It must use a middleman - IC601. IC601 handles so many opera- tions it is electronically divided, having two chip select inputs.

When IC202 wants to send data to IC601, IC202 must also send chip select, clock, write pulses and address information to support the data.