Apple Scanner General Maintenance

The optical block and drive belt, with the belt tension lock screw and pulley lever (Apple Technical Procedures Figure 2-5)

The parts of the Apple Scanner that need routine attention are the glass, the fluorescent lamp, the drive belt and gears, and the fuses. The same procedures apply to the Apple OneScanner, which shares the case and mechanism; Apple's manuals note where the two differ. Faults are diagnosed on the Apple Scanner Troubleshooting Guide.

Safety

Warning: mains voltage is present at the AC switch and plug assembly, the noise filter, the voltage selector on universal models and the transformer, which feeds 28 V AC to the power supply board. Switch the scanner off and remove the power cord before taking off the case top. Apple's manuals give two further cautions:

• Do not pry or press on the glass of the fluorescent lamp. It can shatter and cause serious injury; handle it by the metal ends only.
• Do not loosen the Torx set screw in the middle of the top of the optical block. It holds the CCD and mirror alignment; if it is loosened, Apple's remedy is to replace the whole optical block.

Use ESD precautions when handling the boards.

Cleaning the glass

Switch the scanner off, lift the lid and wipe the glass with water or a mild detergent on a clean, soft, lint-free cloth. Do not use benzene, thinners or other volatile solvents.

Dirt on the underside of the glass shows up as marks on every scan. To reach it, take off the lid and the case top and clean the inside face the same way:

1. Raise the lid to 90°, press in the two clips near the bottom of the lid on each side, and lift it off.
2. Loosen the three Phillips screws along the top rear of the scanner. They stay in the case.
3. Release the two clips that hold the case top, one each side about 6¼ inches from the front, by pressing them in with a flat-blade screwdriver while lifting the rear of the top. Do not twist the screwdriver, or it will mark the case.
4. Swing the case top up and forward. At 90°, unplug the scan switch cable from the LED board at the right front of the top. The LED board has parts that stick out and are easily bent.
5. Refit in reverse, lining up the three tabs at the front with the slots in the bottom case and the LED with its cutout.

Fluorescent lamp

The lamp is the same part, 938-0005, in the 4-bit and 8-bit scanners. Apple's suppliers specified at least 200 hours of continuous use at 40 °C, and Apple found that failed lamps had run more than 230 hours, about 2400 scans. A dim or dead lamp, or dark and light spots on scans, can point to it (see the troubleshooting guide).

The lamp comes out through the access door on the right side of the case without removing the case top:

1. Raise the lid to vertical. Switch the scanner on and off once so that the optical block parks in its home position at the back. The access door must be shut and its latch turned fully clockwise for the scanner to power up, because the latch works an interlock switch.
2. Unscrew the access door latch anticlockwise with a coin or a large flat-blade screwdriver and open the door.
3. Loosen the Phillips screw that holds the lamp assembly to the optical block. The screw stays captive.
4. Raise the wire handle and pull the lamp assembly straight out. If it resists, loosen the screw further.
5. Prise one metal end of the lamp out of its socket with a small flat-blade screwdriver, then the other end.
6. Fit the new lamp with its printed label facing down, into the holder, and press each end home. Wipe off any fingerprints with a dry, soft cloth before fitting, and do not touch the glass again.
7. Slide the assembly back in with its bottom frame in the grooves of the optical block, push it fully home and tighten the screw, which draws the two connectors together. If the screw does not seem to tighten, pull the assembly part way out and reseat it.
8. Put the wire handle down, close the door and turn the latch fully clockwise. Switch on and check that the optical block moves to its home position; if it does not, the latch is not fully home.

Drive belt and gears

The optical block runs on a shaft and a rail, pulled by a toothed belt between a gear pulley at the front, driven by the carrier motor, and a sprung pulley at the rear. If the optical block does not move, Apple's checks are, in order: inspect the belt for damage or debris and clean or replace it; check that the belt is tight with no slack; and check the gears for damage or a build-up of foreign matter.

Belt tension is set at the rear pulley. With the lid and case top off, loosen the tension lock screw on the carrier and swing the pulley lever forward to slacken the belt. To tension it, fit the belt round both pulleys, pull the rear pulley back to take up the slack and tighten the screw on the rear pulley bracket. The belt fixes to the optical block under a clip, with ridges in the plastic slot matching the grooves in the belt. The service parts are the drive belt assembly 076-0323, the belt tension spring (in the miscellaneous hardware kit, 076-0312, pack of 10) and the carrier block gear and pulleys 076-0290.

If the optical block moves once and then stops, check the limit switch for continuity.

Fuses

Apple Scanner fuses

Fuse	Location	Access
Power supply fuses 2 and 3	Power supply board	Lift the left guide rail housing off its rail
Power supply fuse 1	Power supply board	Squeeze and lift out the AC switch cover
Logic board fuse FU1 (4-bit scanner only)	Main logic board	Remove the main logic board

Take off the lid and case top first. Lift each fuse out with a fuse puller, or prise up one end at a time with a small screwdriver, and test it for continuity: a reading of zero ohms means the fuse is good, an open circuit means it has blown. Replace a fuse only with one of the same rating. The Service Source parts list has 250 V fuses of 1 A (076-0284), 2 A (076-0283) and 3 A (076-0285), and labels the two fuses under the guide rail housing "1A" and "3A" and the one under the AC switch cover "2A". It also lists fuse 922-0369 (250 V, 2 A) for power supply board 661-0738, and for the international board 661-0810 either 922-0369 (100-140 V settings) or 922-0370 (200-220 V settings). The 8-bit scanner's logic board is sealed in a metal shield with no user-serviceable fuse; Apple's instruction is not to open the shield.

Voltage selector and conversion

Universal-voltage scanners have a voltage selector under a cover plate on the bottom of the case. Turn the scanner over, remove the Phillips screw and the plate, turn the selector with a coin or large screwdriver to match the mains supply, and refit the plate. Check this setting before powering a scanner that has come from another country; a wrong setting is one of Apple's checks for a dead scanner.

A 110 V scanner has no selector. It can be converted to universal operation by fitting the universal transformer assembly (915-0039 in place of the 110 V assembly, 915-0038), which includes the selector switch; set the selector before switching on. Converting a universal scanner to 110 V needs only the selector. The cover interlock switch also differs by voltage: 076-0300 for 110 V and 076-0315 for 220/240 V.

Related pages

• Apple Scanner
• Apple Scanner Troubleshooting Guide
• Apple Scanner Documentation
• Recommended Tools