Technical Support Document 022 - 5/97

AUTOFOCUS COMPUTER BOX SOFTWARE UPDATE INSTRUCTIONS

REPLACING THE AUTOFOCUS EPROMS

The ZBE Autofocus chassis (Sentinel Enlarger or Satellite Scanning System) is controlled by the AF Computer, the black box mounted behind the head. The Autofocus software is manifest in two EPROMs on the main AF Computer circuit board mounted inside the main shell of the AF box enclosure. Normally, both EPROMs will be replaced when updating the Autofocus software.

NOTE: Before performing this procedure, please read the enclosed sheet entitled REPLACING EPROM SOFTWARE CHIPS. This sheet offers valuable advice on replacing these delicate electronic components.

1. Disconnect the AC power cord from the wall socket. Remove the power cord that goes from the autofocus control box (behind the colorhead) to back of the colorhead, if supplied.
   
2. Unplug any other cabling going to the AF Box.
   
3. Remove the Autofocus Computer Box from the chassis, by removing the four screws at its base. Once these screws are removed, lift the box at one end, and remove the main connector cluster underneath the box. Use a screwdriver to carefully pry off the aluminum plate that holds the four connectors. Work back and forth at each end of this plate until it is free.
   
4. Remove the 7 flat head screws that hold on the back of the autofocus control box. Tilt back the back panel of the autofocus control box. Carefully open the rear panel of the box to gain access to the interrior. Unplug any cables that are connected from the power supply in the lid to the internal circuitry
   
5. Locate the large circuit board inside the autofocus control box. Locate the TWO EPROMs on the circuit board. Due to the many fragile cables inside the AF Box, please be extra careful during these steps. Notice the notch at one end of each EPROM. (The new EPROM must be installed with it's notch in the same direction.) Also notice which EPROM is "U5" and which is "U6". Remove the old EPROMs sing the tool provided.
   

6. Since there are two EPROMs for the Autofocus system, identify the new chips as "U5" and "U6." This identification is located on a paper label on each chip. On this label, the software version code is written.
   
7. On the circuit board itself, identify the two sockets from which the old EPROMS were removed. These sockets are labeled "U5" and "U6" in small white lettering on the green circuit board.
   
8. Install the respective chips into their sockets, again paying close attention to the orientation of the notched ends of the chips with respect to the notches in the sockets. While inserting the new chips, be sure that all pins are located in their respective holes before applying the pressure needed for insertion. When finished, be sure that all pins go completely into the holes in the sockets.
   
9. Re­assemble and re-install the autofocus control box. When connecting the main connector cluster plate, be sure that it is seated level with the bottom exterrior surface of the AF Box. Re-connect the remainder of the cables removed previously.
   
10. Switch on the power. Verify that the system is working properly.

EPROM INSTALLATION GUIDELINES