Macintosh IIci

Macintosh IIci

The Macintosh IIci logic board, 820-0242-A
Specifications
Manufacturer	Apple Computer, Inc.
Type	Desktop personal computer
Released	20 September 1989
Discontinued	10 February 1993
Intro price	US$8,798 at introduction
CPU	Motorola 68030 at 25 MHz
Memory	1 MB or 4 MB standard, expandable to 128 MB with 80 ns or faster SIMMs
Storage	Optional internal 40, 80 or 160 MB SCSI hard drive
Display	—
Sound	Apple sound chip, 8-bit stereo sampling at 44.1 kHz, four-voice wavetable synthesis
Graphics	Built in, DB-15 port; shares main memory for the frame buffer
ROM	512 KB, 32-bit clean
FPU / coprocessor	Motorola 68882 at 25 MHz
Media	Internal 1.4 MB SuperDrive
Ports / interface	Two ADB, two RS-232/RS-422 mini DIN-8 serial, DB-25 SCSI, DB-19 floppy, DB-15 video, stereo sound jack
Expansion	Three NuBus slots and a cache-card connector
Power	100–240 VAC auto-configuring, 50–60 Hz, 90 W maximum
Dimensions	5.5 × 11.9 × 14.4 in (14.0 × 30.2 × 36.5 cm)
Weight	14 lb (6.4 kg) with an internal hard drive
OS / Firmware	—
Predecessor	Macintosh IIcx
Successor	Macintosh Quadra 700
Model no.	M5780 (order no. M5710LL/A); Gestalt ID 11

The Macintosh IIci, introduced on 20 September 1989, is the Macintosh IIcx case with a faster processor and three firsts for the Macintosh II line: a 32-bit clean ROM, built-in video and a cache connector.

Everything on this page that is a number comes from Apple's own Service Source for the IIcx, IIci and Quadra 700, hosted on this wiki, or from a named community source.

Specification

Apple's specification

Item	Figure
Processor	Motorola 68030 at 25 MHz
Coprocessor	Built-in floating-point unit (Motorola 68882)
RAM	1 MB, expandable to 128 MB (80 ns or faster SIMMs)
ROM	512 K, 32-bit clean
Expansion	Three NuBus slots
Video	One DB-15 port for built-in video
Video modes	640 × 480 at up to 256 colours or greys (8 bits per pixel); 640 × 870 at up to 16 greys
Sound	Apple sound chip: 8-bit stereo sampling at 44.1 kHz, four-voice wavetable synthesis
Line voltage	100–240 VAC, automatically configured
Frequency	50–60 Hz, single phase
Maximum power	90 W, monitor excluded
Dimensions	5.5 × 11.9 × 14.4 in (14.0 × 30.2 × 36.5 cm)
Weight	14 lb (6.4 kg) with an internal hard drive

All of that is Apple's.

Why the 32-bit clean ROM matters for repair

The IIci is the first Macintosh whose ROM contains no 24-bit addressing code, so no MODE32 and no 32-Bit System Enabler is needed to use more than 8 MB. On a IIx or IIcx, a machine reporting 8 MB with 32 MB fitted is a software configuration problem. On a IIci it is a fault: check the SIMMs, the sockets and the bank population before anything else.

Built-in video takes memory

The IIci has no VRAM. The built-in video draws its frame buffer from main memory — between 64 K and 320 K depending on the resolution and depth in use. Two consequences on the bench:

• "About This Macintosh" always shows slightly less RAM than is fitted. That is the frame buffer, not a bad SIMM.
• Built-in video performance depends on which memory bank is populated. The machine is faster with the video frame buffer in a bank that is not also being hammered by the processor, which is why IIci owners have always argued about SIMM placement. It is a performance characteristic, not a fault.

The cache connector

The IIci has a dedicated connector for a 32 K level-2 cache card, provided as a plug-in card on early machines and soldered down on later ones. Apple's developer note gives its signal definitions, including that the card should pull /BGACK up to +5 V.

If your machine has the card, it is a part you can reseat — which makes it worth reseating before you suspect anything more expensive. If it does not, there is nothing to reseat and nothing missing.

Power

The IIci uses the same physical supply family as the IIcx, the IIvi/IIvx and the Quadra 700, at different ratings.

Apple part numbers and rated outputs for this supply family

Apple P/N	Fitted to	Manufacturer and model	Rated output
699-0392	IIci	Astec AA15830	+5 V 12 A • +12 V 1.5 A • −12 V 1.0 A • +5 V 1 mA continuous
614-0004	IIci, Quadra 700	Astec AA15831 • GE 9T89Y5005G11	+5 V 12 A • +12 V 1.5 A • −12 V 1.0 A • +5 V 1 mA continuous
614-0009	Centris 650, Power Macintosh 7100	Astec AA16870 • Delta SMP-120EB	+5 V 15 A • +12 V 2.5 A • −12 V 0.6 A • +5 V 1 mA continuous

Those are rating-plate readings taken from physical units by 68kMLA members, not Apple publications, and they are quoted here because they are checkable against the label on your own supply. Note that there is no −5 V output on any of them.

The "+5 V 1 mA continuous" line is the trickle rail, and it is the first useful go/no-go check on a dead machine. It is alive whenever the mains lead is plugged in, switched on or not, because it keeps the soft-power circuit and the clock running. Present means the primary side is working and the fault is downstream; absent means the fault is in the mains input, the primary switcher or the standby circuit.

Console5 records the IIci supply as a GE 9T89Y5005G11 or a Delta SMP-120EB, which matches the Apple 614-0004 and 614-0009 entries above.

What Apple does and does not publish

Apple publishes no rail tolerance and no power-supply adjustment procedure for the IIcx, IIci or Quadra 700. The Service Source contains no acceptable-range table for any rail and no trimmer adjustment; every power fault in the symptom charts ends in "Replace power supply". The "+5 V 4.85–5.15 V / +12 V 11.9–12.7 V" table that circulates on pages of this era is Apple's Macintosh Plus procedure — genuine there, where it uses voltage test cable 077-0135 on the external floppy port — copied onto machines it was never written for. Neither it nor any invented substitute appears on this page.

What you can do instead is measure against a known load. Each rail at the logic-board power connector should sit close to nominal with the machine running and should not move when a drive spins up. A rail that sags under load points at the supply; a rail that measures as a short to ground with the supply disconnected points at the logic board.

Recapping the supply

You may open it. Understand what is live in it first: it is mains-rectified, so with the cover off and the lead plugged in the fuse, input filter, bridge rectifier and reservoir capacitors sit at mains potential and hold a charge after the plug comes out. Unplug, discharge each large reservoir through a 1 kΩ / 5 W resistor, and confirm with a meter before a tool goes near the primary side. If two reservoir capacitors sit in series across the rectified mains, replace both together with matched parts — a single capacitor in place of the pair will fail on European mains, violently.

Battery

A 3.6 V lithium half-AA cell in a holder on the logic board keeps the real-time clock and parameter RAM alive with the machine unplugged.

• Set a meter to the 10 V DC range.
• Positive probe on the positive end of the cell, negative probe on the other.
• Replace the cell if it reads below 2.8 V.

2.8 V is this machine's figure. It is not the 3.2 V of the II/IIx/IIfx, the Centris machines and the larger Quadras, and not the 3.0 V of the IIsi and the LC series. Apple's thresholds are machine-specific and are routinely transplanted between pages; use the one printed in your own machine's manual.

Apple publishes no replacement interval, and none is invented here: a cell above 2.8 V is doing its job, and one below it should come out today whatever its age.

If it has leaked

This is a lithium cell, so neutralise with bicarbonate of soda, not vinegar. Vinegar is the right treatment for alkaline leakage, which is basic; it is the wrong treatment here and it adds water and chloride to an already corroded board. Use a paste of sodium bicarbonate and distilled water, rinse with distilled water, follow with isopropyl alcohol and dry thoroughly. Then buzz out every track running away from the holder, and check the underside of the board — electrolyte wicks down through vias.

See Battery Explosion, Capacitor or Corrosion Damage and Battery Refurbishment.

Take the cell out before the machine goes into storage.

Apple's symptom chart puts "replace battery" as the first cure for a clock that does not run on this machine, ahead of the logic board. Apple's developer note describes the parameter RAM as having seven-year battery protection — which is the design intent, not a service interval, and tells you nothing about a cell that has been in the machine since 1992.

Capacitors

Logic board 820-0242-A (1989). Fourteen electrolytics:

Macintosh IIci logic board 820-0242-A

Value	Working voltage	Quantity	Package
47 µF	16 V	8	Surface-mount
470 µF	25 V	3	Axial
220 µF	25 V	1	Axial
10 µF	16 V	2	Surface-mount

Note the axial voltage ratings. MacDat records the IIci's four axial capacitors as 25 V parts, against 16 V on the otherwise very similar IIcx board, and flags the difference explicitly on both pages. Fit 25 V here. A higher rating is never a hazard; a lower one is exactly the class of mistake this wiki exists to stop.

Console5 carries no IIci capacitor list, so unlike the IIx and IIcx this complement rests on two sources rather than three: MacDat's reference list and Recap-a-Mac's annotated photograph, hosted here as File:Mac IIci Recap Guide.jpg. Both are readings of physical boards; Apple published no component-level capacitor data for any Macintosh of this era. Read the value and voltage off each can before you lift it.

Macintosh IIci logic board 820-0242-A. The battery holder (BT1) is at top right beside the RTC and its 32.768 kHz crystal; the ROM DIPs and ROM SIM socket are on the right-hand edge. Source: Recap-a-Mac.

The failure pattern is the family one — audio first, then intermittent starting, then visible residue. See Capacitor Failure Symptoms.

Connectors and sockets

Oxidised contacts cause more intermittent faults on a machine this age than failed silicon does, and they are the cheapest thing to put right.

• SIMM sockets. Clean with isopropyl alcohol on a swab and reseat. Do not take an abrasive to a module's gold fingers — once you are through the plating, the base metal oxidises and then transfers to every socket the module touches.
• VRAM sockets. Same treatment. Video faults that come and go when the case is knocked usually start here.
• NuBus and PDS slots. Inspect for bent contacts and debris before a card goes home; check the card's edge fingers too.
• ROM SIMM socket, where one is fitted. A poorly seated ROM gives a machine that chimes and does nothing else.
• Logic-board power connector. Look for browning or a distorted housing. A discoloured power connector is a warning, not a cosmetic problem.
• ADB, serial, SCSI and floppy connectors. Reseat; check ribbon cables for cracked conductors where they fold.

A contact cleaner such as DeoxIT D5 earns its place on genuinely corroded contacts. It is not a preventive treatment and it does not belong on clean gold.

Two more specific to this board: the cache connector, where one is populated, and the ROM DIPs at UM10–UM13 alongside the ROM SIM socket. A poorly seated ROM gives a machine that chimes and does nothing else.

Cleaning

Opening the case

The IIcx and IIci chassis is the easiest of the Macintosh II family to work on: release the catches and the cover lifts away, and the logic board slides out of the bottom case on rails once the drives and the supply are clear. There are no hidden screws.

Inside

• Compressed air and an anti-static brush on the logic board, the supply and the fan. Hold the fan blade still while you blow it: spinning a fan with compressed air drives it as a generator and puts a reverse voltage back down its cable.
• Isopropyl alcohol (99 %) and a soft brush for grime, working outwards from each capacitor and from the battery holder.
• Check the underside of the board as well as the top. Both battery and capacitor electrolyte travel through vias.

Outside

• A damp microfibre cloth and mild detergent. No abrasives, no solvents — the texture on these shells does not survive either.
• ADB keyboards come apart for washing: keycaps off, warm soapy water, dry them completely, then clean the contacts with isopropyl alcohol.
• Mouse ball out, rollers scraped and wiped with isopropyl alcohol.

The platinum-grey plastics yellow with age. The discolouration is in the body of the plastic rather than on the surface, so cleaning will not shift it; see Retrobrite for what can be done and what it costs in brittleness.

Floppy drive

The 1.4 MB Apple SuperDrive is direct drive. It has no belt. Advice to fit a new belt to a sluggish or non-ejecting SuperDrive — including to the auto-inject version — is wrong: there is nothing there to replace. What these drives actually suffer is hardened grease on the head carriage and eject rails, dust in the mechanism, and dirty or worn heads. On manual-inject drives a worn eject gear is a genuine and common failure.

• Clean the heads with isopropyl alcohol on a lint-free swab, supporting the upper head arm so it is not sprung.
• If the rails are stiff, re-lubricate with a silicone grease — not white lithium grease, which gums up as it ages.
• If a disc will not eject, hold the mouse button down while switching the machine on to run a full eject cycle before taking anything apart.

See Macintosh Floppy Drive Maintenance.

Hard disk

The original SCSI mechanisms are past thirty years old and the usual failures are a stuck spindle, dried head-park grease and dead controller electronics. Solid-state replacements — BlueSCSI, ZuluSCSI, SCSI2SD — are quieter, cooler and considerably more reliable, and they let you keep the original drive on a shelf.

Whatever you fit, get the termination right: the drive at the end of the internal bus must be terminated, and the computer itself is always SCSI ID 7. See Macintosh HDD Maintenance.

Apple's own SCSI notes for this chassis: the external device's ID switch must not be set to 0 (the internal drive) or 7 (the computer), and Apple resolves both "drive icon does not appear" and "data is lost or corrupted" to a termination check.

Easter egg

Set the system date to 20 September 1989 — the machine's introduction date — set the display to 8-bit colour, and restart holding Command-Option-C-I. A colour photograph of the IIci design team appears; click the mouse to continue.

The IIfx has the same egg on its own date with its own key combination, and displays the same picture.

Things that are not faults

• Slightly less RAM reported than fitted. The built-in video frame buffer lives in main memory.
• A cache connector with nothing in it. The card was an option and was soldered down on later boards.
• 640 × 480 at 8 bits being the limit of the built-in video. That is Apple's published figure; more needs a NuBus card.

Storage

• Take the battery out.
• Store dry and at room temperature — not a loft, not a garage.
• If the logic board comes out, bag it anti-statically and lay it flat.
• Nothing needs periodic running. "Power it up every few months to keep the capacitors formed" is repeated widely and supported nowhere for machines of this kind. The real hazard to a stored Macintosh is the cell in the battery holder, and removing it costs nothing.

Related pages

• Macintosh IIcx — the same case, one generation earlier
• Macintosh Quadra 700 — the same case, 68040
• Macintosh IIx
• Macintosh IIcx/IIci/ Quadra 700 Service Source
• Macintosh IIci Developer Note
• Capacitor Failure Symptoms
• Battery Explosion, Capacitor or Corrosion Damage
• Recommended Tools