Kodak 5020, 7020, 4020, (9020/CINE) service manual Auto Focus

Service Manual SM 2547-1

AUTO FOCUS

The AUTO FOCUS feature is installed in the EKTAPRO Model 5020,9020 and 9020/CINE.

A “low” FOCUS EXT signal from the MICROCONTROLLER enables the AUTO FOCUS PCB while a “high” signal disables the AUTO FOCUS to ensure a sharpness correction for the projected slide. If a manual sharpness correction was necessary the AUTO FOCUS MOTOR moves back to its primary position after the next slide change. The AUTO FOCUS MOTOR is running until both receivers has the same light input. The FOCUS MOTOR stops at the time the light input on both Photo transistors is equal. The direction for the focus movement is defined by either receiver port 1 or port 2.

An electronic circuit will determine the operating voltage for the FOCUS MOTOR (running forwards or backwards) to ensure to have the same speed in both directions. This regulation is necessary because the LENS CARRIER is basic loaded with a spring in one direction.

To ensure that the AUTO FOCUS function works properly it is very important to use the same kind of slide frames. Mixing up glass slides with other slides will bring the projected image out of focus because there is only one reference point for the lens position to get a sharp and clear projected image on the screen.

If glassless slide frames are in use, it could be, that the borders of the projected image are out of focus. It depends on the IR-Beam which is only sensing the center of the slide.

Slide

Prism

IR-

Trnasmitter

	Prism
		Focus Command
		from Keyboard or
	IR-	Remote Control
	Receiver
T1	T2	MASTER
		BOARD
AF	5V DC
BOARD	GND
	Foc Ext2
FOCUS	Foc Ext1	MICRO
LOGIC	Speed	CONTROLLER
	Direction
Focus Motor
M		FOCUS
		MOTOR
		CONTROL
figure 3-13

03/98 3-16 Kodak AG, Stuttgart