Apple Scribe Printer General Maintenance

An Apple Scribe on display, with its clear lid (photo: Marcin Wichary, CC BY 2.0)

Preventive maintenance and adjustments for the Apple Scribe Printer, from Apple's Apple Scribe Printer Technical Procedures. Unlike most of Apple's printer manuals, this one gives the manufacturer's own maintenance schedule, with cleaning and lubrication points and the oil to use. Fault-finding is on Apple Scribe Printer Troubleshooting Guide.

Safety

The Scribe runs from the mains through an internal line transformer, with a mains switch, fuse holder and line filter inside the case. Switch it off and disconnect the power cord before opening it. Apple's initial checks include looking for cracked or burnt power cord insulation, a missing earth pin, and burn marks on the case.

Maintenance schedule

Apple's table gives three intervals: work the user does once a year, work done by the dealer during any preventive or corrective service, and work done by the dealer once a year or every 500,000 lines of print.

Manufacturer's recommended maintenance schedule (Apple's p. 5.3)

Task	User, yearly	Dealer, at service	Dealer, yearly or 500,000 lines
Clean and lubricate the carriage shaft	Yes	Yes	Yes
Clean the platen		Yes	Yes
Check the drive belt tension		Yes	Yes
Clean the print head		Yes	Yes
Clean the paper-out sensor		Yes	Yes
Clean the front guide bar		Yes	Yes
Clean and lubricate the carriage bearing stud, carriage drive motor idler gear stud, paper feed motor idler gear studs and drive belt pulley shafts		Yes	Yes
Lubricate the platen sleeve bearings			Yes
Lubricate the tractor sleeve bearings			Yes

Materials: a clean absorbent cloth or gauze, a small soft brush, cotton swabs and isopropyl alcohol for cleaning, and Tellus oil #46 (Apple part 970-0006) for lubrication. Before oiling any part, wipe off the old oil, dust and dirt with a cloth slightly dampened with alcohol.

Routine cleaning and lubrication

Apple's procedure for every service:

1. Switch off. Take the printer assembly out of the case.
2. Remove the tractor assembly (one screw at each end; lift and wiggle it free) and the platen (prise out the two plastic tabs on each side).
3. Clean the platen surface with a cloth moistened with alcohol.
4. Clean the carriage shaft with alcohol, put two drops of oil on each side of it, slide the carriage from side to side to spread the oil, and wipe off the excess with a dry cloth.
5. Clean the paper-out sensor with a soft brush or an alcohol swab.
6. Take out the print head and clean it with an alcohol swab. Refit the rubber cap over its connector.
7. Clean the front guide bar with an alcohol cloth.
8. Carriage bearing stud: prise the bearing off, clean the stud, add one drop of oil, refit the bearing.
9. Carriage drive motor idler gear: loosen the drive belt and slip it off the gear, remove the E-clip and pull the gear off (it takes some effort), clean the stud, add one drop of oil, and refit the gear and E-clip with the outer lip on the gear.
10. Paper feed motor idler gears: move the carriage fully right, remove the two feed rollers and the two screws holding the paper pan, unplug the paper-out sensor cable from the logic board and lift out the pan. Remove the E-clip and washer from the upper bearing, clean its stud and add one drop of oil, put a small drop behind the lower bearing without removing it, and reassemble. Route the sensor cable under the square rod above the logic board, and make sure the copper earthing clip is under the left-hand paper pan screw. The smaller cylinders of the feed rollers go to the front.
11. Left drive belt pulley: lift the pulley assembly out of its slot, slide the shaft out without losing the washers, clean it, add one drop of oil and reassemble.
12. Right drive belt pulley: remove the two screws at its base and lift out the assembly, push the shaft down from the top and pull it out from below, clean it and add one drop of oil, then refit it with the small end on top. Leave the pulleys in the assembly; they are hard to reassemble.
13. Refit the drive belt and set its tension (below).
14. Refit the platen and tractor assemblies and the ribbon cassette, and run the loopback test.

Yearly maintenance

Once a year or every 500,000 lines, add:

1. Platen sleeve bearings: remove them from the platen assembly, clean the shaft and bearings with an alcohol cloth, put one drop of oil on each end of the shaft, wipe off the excess and refit.
2. Tractor sleeve bearings: pull off the right side panel of the tractor assembly and ease the left panel off the end of the sleeve, wipe the shaft ends clean, put one drop of oil on each end and refit the panels.
3. Reassemble and run the loopback test.

Drive belt tension

A wrong belt tension causes horizontal registration errors (uneven vertical lines) and home position errors. A slight unevenness at the left margin, column 0, is normal and hard to remove. Before adjusting the belt for a home position error, check that the home position sensor switch is firmly fixed to the chassis.

1. Switch off and disconnect the power cord. Remove the printer cover.
2. Move the carriage fully to the right.
3. Press a spring gauge (Apple 077-0014 or equivalent) down on the top run of the belt, halfway between the carriage and the left-hand pulley, until the belt is 10 mm (about 3/8 inch) above the bottom plate.
4. The gauge should read 1/4 to 1/2 lb (175 g ±25 g). If it does not, adjust the belt following Apple's steps and measure again.

Print head gap

If the head is too far from the platen, printing is uniformly light; if it is too close, printing is too black with a grey smear.

1. Remove the ribbon cassette and pull off the clear plastic paper guide on the left of the carriage.
2. Measure the gap between the print head and the platen. It should be 3.5 mm ±0.5 mm (about 1/8 inch).
3. To adjust, loosen the right-hand adjustment screw without removing it, and loosen the left-hand screw just enough for the head positioning plate to move. The plate pivots at the left.
4. Move the head forward or back to 3.5 mm, tighten the screws and measure again.
5. Run the self-test, and refit the paper guide.

Related pages

• Apple Scribe Printer Troubleshooting Guide
• Apple Scribe Printer
• Apple Scribe Printer Documentation