Apple Lisa General Maintenance

Apple Lisa interior

The Apple Lisa and Lisa 2 are now more than forty years old. Apple's owner's guide says the Lisa "requires almost no day-to-day maintenance"; the work that matters now is removing the I/O board battery pack, servicing the power supply and checking the video adjustments.

Safety

• The CRT anode holds about 15,000 V DC even when the power is off, and can recover some charge after it has been discharged. Apple says to discharge it again if a procedure takes more than 30 minutes, and to remove all metal objects from hands and arms before working near it. See CRT Discharge Procedure.
• The front and back panels have safety interlock switches that cut power to the system when a panel is removed, but they do not cut power to the power supply. Unplug the Lisa before opening the cabinet.
• The power supply's primary reservoir capacitors hold a charge after power-off. Measure across them before touching the primary side; the parts and their positions are on Apple Lisa Capacitor Replacement Guide.

Battery pack

The I/O board battery pack, with corrosion at the cell ends

The I/O board carries a 4.8 V NiCd pack with an on/off switch beside it. Apple's set-up procedure describes "the set of four batteries on the lower right side of the I/O board" and has the technician set the switch to ON (toward the left). It powers the clock and parameter memory for up to 10 hours while the Lisa is unplugged; while the Lisa is plugged in, even switched off, the standby supply does this. The Macintosh XL I/O board has no batteries.

• Remove the cells from any stored machine before powering it up or doing any other work.
• NiCd electrolyte is alkaline. Neutralise the residue, clean with isopropyl alcohol and check continuity on every trace in the affected area.
• See Battery Explosion, Capacitor or Corrosion Damage for the method.

Switching SW1 off for about 5 seconds and back on clears parameter memory, which is one of Apple's first troubleshooting steps.

Owner maintenance

Apple's suggested maintenance table has three entries, each done when needed: clean the glare filter when the screen is dusty, clean the mouse ball when the mouse response is unreliable or the ball is sticky or dusty, and clean the housing when it is dirty.

Screen and glare filter

The screen attracts dust through static charge. Wipe it every few weeks with the treated cloth supplied with the Lisa. To clean under the glare filter, remove the front panel, release the filter from its metal clips and wipe both sides. Wash a spotted filter in warm soapy water and dry it with a towel. Clean the screen glass with glass cleaner sprayed onto a soft cloth, never onto the glass, so that no drops run into the cabinet.

Mouse

After several hundred hours of use, dust inside the mouse can make pointer control uneven. Unscrew the cord from the back of the Lisa, turn the mouse over and turn the ring from L (locked) to O (open), remove the ball and clean it, wipe the inside of the case and the two rollers with a clean dry cloth, then refit the ball and turn the ring back to L. See Apple Lisa Mouse.

Housing

The cabinet, keyboard and mouse housing can be cleaned with most commercial cleaners, but not with anything containing kerosene or pine oil, which damages the plastic. Unplug the Lisa first, do not spray near the air vents or the disk drive slot, and do not spray solvents on the keys.

Power supply

Apple's 1982 Lisa Hardware Manual gives the Lisa supply's outputs and permitted variation:

Lisa power supply outputs (Figure 10-1)

Rail	Variance	Limits as printed	Current
+5 V	±5%	5.25 V / 4.76 V	4 to 8 A
+12 V	±8%	13.0 V / 11.1 V	0.35 to 2.0 A
+33 V		36 V max, 32 V min	0.3 to 0.7 A
-5 V	±10%	-5.5 V / -4.5 V	0 to 0.2 A
-12 V	±10%	-13.2 V / 11.8 V	0.01 to 0.2 A
+5 V standby	±5%	5.25 V / 4.75 V	0 to 0.1 A

The -12 V lower limit is printed as 11.8 V; ±10% of 12 V gives 10.8 V. The +5 V standby output is not switched off by the on/off signal. These figures date from 1982 and describe the original supply design (schematic 050-4011). Apple's Level I service procedures give no voltage adjustment for the supply.

The "+5 V 4.85-5.15 V, +12 V 11.9-12.7 V" table found on other Apple pages comes from the Macintosh Plus service procedure and does not apply to the Lisa.

Capacitor lists for both documented supplies, and the X capacitors across the mains input, are on Apple Lisa Capacitor Replacement Guide.

Memory boards

The Lisa takes two identical memory boards (661-93105). One gives 512 KB and two give 1 MB, Apple's maximum; Apple notes that third-party boards can reach 2 MB. Both boards must be fitted to run the diagnostic diskette and any version of the Lisa Workshop, so a machine that will not run diagnostics with one board is not necessarily faulty.

Video adjustments

Apple's video adjustments are horizontal phase, brightness and contrast, the yoke, height, width, vertical linearity and centring, and the magnets on the yoke. Apple notes that the adjustments can slip in shipping. The customer controls are brightness and focus at the upper rear, above the power socket, and contrast in software; everything else is inside the video assembly. Let the Lisa warm up for 10-15 minutes before adjusting, because the picture expands and moves slightly as it warms.

The Lisa dims the screen after several minutes without activity, to protect against burn-in.

In Apple's video repair table, "unable to adjust brightness" and "unable to adjust focus" both list replacing the power supply first, then the video board and other parts.

Drives

• The Lisa 1's two 5.25-inch FileWare ("Twiggy") drives hold 871 KB formatted each.
• Every Lisa 2 has one 3.5-inch micro disk drive, 400 KB formatted. Do not spray anything near its slot. See Macintosh Floppy Drive Maintenance and Floppy Drive Repair.
• The external ProFile (4.98 MB formatted on the Lisa 1 specification) connects to the built-in parallel port at the back of the Lisa. The Lisa 2/10 has an internal 10 MB hard disk on an internal parallel port.

Diagnostics

The start-up self-test, the boot ROM and I/O ROM codes and Apple's error numbers are covered on Apple Lisa and Apple Lisa Troubleshooting.

Related pages

• Apple Lisa
• Apple Lisa Troubleshooting
• Apple Lisa Capacitor Replacement Guide
• Apple Lisa Mouse
• CRT Discharge Procedure