Macintosh IIfx
 | |
| Macintosh IIfx with an Apple colour monitor (All About Apple museum) | |
| Specifications | |
|---|---|
| Manufacturer | Apple Computer, Inc. |
| Type | Desktop personal computer |
| Released | 19 March 1990 |
| Discontinued | 15 April 1992 |
| Intro price | US$8,970-10,970 at introduction |
| CPU | Motorola 68030 at 40 MHz |
| Memory | 4 MB, expandable to 128 MB (eight 64-pin 80 ns 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 | None built in; requires a NuBus video card |
| ROM | 512 KB, 32-bit clean |
| FPU / coprocessor | Motorola 68882 at 40 MHz |
| Media | Internal 1.4 MB floppy drive; optional second internal drive |
| Ports / interface | Two ADB, two RS-232/RS-422 serial (mini DIN-8), SCSI (DB-25), stereo sound jack |
| Expansion | Six NuBus slots, one 120-pin processor-direct slot |
| Power | 100-240 V AC auto-configured, 48-62 Hz, 230 W maximum |
| Dimensions | 5.5 × 18.7 × 14.4 in (14.0 × 47.4 × 36.5 cm) |
| Weight | 24-26 lb (10.9-11.8 kg), depending on drives |
| OS / Firmware | — |
| Predecessor | Macintosh IIx |
| Successor | Macintosh Quadra 900 |
| Codename | F-16, F-19, Stealth, Blackbird, Zone 5, Four Square, IIxi, Weed Whacker |
| Model no. | M5525 (Gestalt ID 13) |
The Macintosh IIfx is a desktop Macintosh introduced by Apple on 19 March 1990 and discontinued on 15 April 1992.[1] It puts a 40 MHz 68030 and 68882 into the six-slot Macintosh II case, with a 32K static RAM cache, its own 64-pin memory modules and two I/O processors that take floppy, ADB and serial work away from the main CPU.[2] Its 40 MHz clock was the fastest Apple used until the Quadra 840AV of 1993.[3] Apple's service manual covers it together with the II and IIx.[4]
Specifications
[edit | edit source]| Item | Specification |
|---|---|
| Processor | Motorola 68030 at 40 MHz with built-in paged memory management unit; 32-bit address and data buses[4] |
| Coprocessor | Motorola 68882 at 40 MHz[2] |
| I/O processors | Two 6502 processors with 64K of static RAM, managing the serial ports, ADB and floppy drives[2] |
| RAM | 4 MB on 64-pin SIMMs; Apple printed "expandable to 8 MB", with more "possible with greater-capacity RAM chips"; optional parity[4][2] |
| Cache | 32K high-speed static RAM[2] |
| ROM | 512K, with 32-Bit QuickDraw built in[4][2] |
| Parameter RAM | 256 bytes, kept by a lithium battery[2] |
| Floppy drive | Internal 1.4 MB; optional second internal 1.4 MB drive[4] |
| Hard drive | Optional internal 40, 80 or 160 MB[4] |
| SCSI | 5 MB/s, eight devices maximum; DMA-capable[4][2] |
| Expansion | Six NuBus slots (96-pin); one processor-direct slot (120-pin)[4][2] |
| Serial | Two RS-232/RS-422 ports, 230.4 kbit/s, up to 0.920 Mbit/s when externally clocked[2] |
| Sound | Apple Sound Chip: 8-bit stereo sampling at 44.1 kHz, four-voice wavetable synthesis; stereo jack, 1.5 V peak-to-peak per channel[4][2] |
| Mains input | 100-240 V AC, automatically configured; 48-62 Hz single phase; 230 W maximum, not including the monitor[4] |
| DC power | 132 W maximum: +5 V 18.0 A, +12 V 2.5 A, -12 V 1.0 A[2] |
| NuBus power budget | All cards together: +5 V 12.0 A, +12 V 1.05 A, -12 V 0.600 A[2] |
| ADB power | 500 mA maximum for all devices[2] |
| Environment | Operating 10-35 °C; storage -40 to 47 °C; 5-95 % relative humidity, non-condensing; 0-3,048 m[2] |
| Size and weight | 5.5 × 18.7 × 14.4 in (14.0 × 47.4 × 36.5 cm); 24 lb (10.9 kg) in the Service Source, 26 lb (11.8 kg) in the owner's booklet, varying with the drives fitted[4][2] |
Hardware
[edit | edit source]Memory
[edit | edit source]The IIfx uses 64-pin SIMMs that fit no other Macintosh. Each standard module carries eight 1 Mbit 80 ns DRAMs; the parity module carries nine RAM chips and a parity chip.[2] The eight sockets are filled four at a time, and eight 16 MB SIMMs give 128 MB.[1] The 512K ROM is 32-bit clean. Parity checking was a factory option that had to be specified when the machine was ordered.[2]
Apple's symptom charts for the II, IIx and IIfx replace Apple-labelled SIMMs made by NEC with a date code of 9052 or below for an error chord at start-up, failure to boot, ghosting or lost video, a hang when the first application launches, and an ID error followed by a lock-up.[4]
The ROM is on a ROM SIMM (J1), and the board does not work without a IIfx ROM in that socket.[3][5]
I/O processors
[edit | edit source]On the IIfx the main processor does not drive the floppy controller, ADB or the serial controller directly. Two Apple custom chips do: one runs the SWIM floppy controller and ADB, the other the SCC serial controller.[6] Apple's owner's booklet describes them as two 6502 processors with 64K of static RAM; Low End Mac gives their clock as 10 MHz.[2][3]
Apple's Technical Note HW 9 lists what this breaks:[6]
- Software that accesses the ADB transceiver or its VIA registers directly does not work, and there is no workaround.
- The SCC processor has an "IOP Bypass" mode. Apple's IIfx Serial Switch control panel sets a bit in parameter RAM that is read at start-up: "Faster" (the default) uses the I/O processor, "Compatibility" lets the CPU drive the SCC directly. A program cannot tell which mode it is in, and one that calls the SCC directly in "Faster" mode crashes the machine.
- The VIA1 Wait/Request bit is gone, and the vSync bit has moved. Apple's _HWPriv trap (selector 7) replaces direct writes to vSync, and works on the IIfx only in IOP Bypass mode.
- VIA2 is gone; its functions moved to other chips.
- A NuBus read-modify-write (TAS) followed at once by an ordinary read or write hangs the system. Apple's fix is five NOP instructions between them.
- Programs that make synchronous serial calls or asynchronous disk calls with interrupts off hang the machine, because the new drivers are interrupt-driven.
The note sets minimum versions for Apple software: AppleCD SC driver 3.0.1 or later and MacsBug 6.2 are required, and EtherTalk driver 2.0.2 is recommended because earlier versions "do not perform as well".[6] The IIfx shipped with System 6.0.5.[2]
SCSI
[edit | edit source]The IIfx needs its own termination hardware, set out in the Service Source's "Macintosh IIfx SCSI Termination" procedure:[4]
- External devices are terminated with Apple's SCSI Cable Terminator II. If an external device has built-in termination, disable it and fit the Terminator II. Never fit more than one Terminator II on the chain; Apple warns this can damage the equipment. Low End Mac describes it as the IIfx's black terminator.[3]
- An internal SCSI filter gives the termination capacitance needed by third-party drives and by Apple internal drives shipped before 19 March 1990. It fits between the hard drive data cable and the drive.
- Machines shipped without an internal hard drive have a SCSI termination block and the filter on the logic board's SCSI connector. When a drive is fitted, remove the block and move the filter to the drive; Apple warns that leaving the filter on the logic board causes SCSI failures.
The logic board replacement procedure notes that a filter or terminator may be needed when a board is changed.[4] The hardware supports SCSI DMA, which the Macintosh system software of 1990 did not use.[6]
Expansion
[edit | edit source]The processor-direct slot is in front of the far-right NuBus slot, and a card in it makes that NuBus slot unusable. Apple warns that a PDS card not designed for the IIfx can damage the card, the computer or both.[2] The IIfx has no built-in video; one NuBus slot holds the video card.[2] The programmer's switch (reset and interrupt) clips into the air vents on the right-hand side.[2]
A Macintosh II or IIx could be upgraded to a IIfx by exchanging the logic board. Apple's kit included a new hard drive power cable and a IIfx decal for the bottom cover.[4]
Power supply
[edit | edit source]Apple part 661-0542 (the II and IIx use 661-0375).[4] Apple rates the machine at 230 W from the mains and the supply at 132 W of DC output, with maximum currents of 18.0 A on +5 V, 2.5 A on +12 V and 1.0 A on -12 V.[4][2] The fan speed varies: Apple says it speeds up when more cards are installed.[2][3]
Apple's Guide to the Macintosh Family Hardware gives the output limits for the Macintosh II, IIx and IIfx supplies: +5 V 4.90–5.20 V, +12 V 11.50–12.80 V and −12 V −13.40 to −10.80 V.[7] The Service Source has no adjustment for the supply, and every power fault in its symptom charts ends at "replace power supply". The only rail check in the charts is to verify the +5 V and +12 V lines to an internal hard drive that does not spin.[4] The supply runs from rectified mains, and its reservoir capacitors hold a charge after it is unplugged: discharge them and confirm with a meter before working on the primary side.
Batteries
[edit | edit source]The IIfx has two lithium cells in holders on the logic board, BT1 and BT2.[4][5] EveryMac lists them as 3.6 V.[1] Apple's test: remove the cover and drive mount, set the meter to the 10 V DC range, put the positive probe on the end marked "+" on the logic board, and replace the battery if it reads below 3.2 V. To remove a cell, prise the latch away from the holder with a small flat-blade screwdriver and lift off the cover.[4] Apple's charts check the batteries for no power, intermittent shutdown and a completely dark screen with the fan off.[4]
Take the cells out before storing the machine. If one has leaked, neutralise the residue with bicarbonate of soda (vinegar is for alkaline cells), rinse, dry with isopropyl alcohol, and check the tracks around the holders on both sides of the board. See Battery Explosion, Capacitor or Corrosion Damage and Battery Refurbishment.
Capacitors
[edit | edit source]
The logic board (820-0282-B) has two sets of pads at each surface-mount electrolytic position, one for an aluminium electrolytic and one for a tantalum.[5] Console5 reports that some boards were built with aluminium electrolytics at only two surface-mount positions, C9 and C24, and some with them throughout.[8] Check each position before ordering parts; the tantalums do not leak like the aluminium parts.
| Positions | Value | Type |
|---|---|---|
| C5, C9, C10, C21, C22, C23, C24, C38, C43, C44, C48, C54, C57, and one unnumbered position near C3/C5 | 47 µF 16 V | Surface-mount |
| C27 | 10 µF 16 V | Axial |
| C221, C223, C224 | 470 µF 16 V | Axial |
| C226 | 220 µF 16 V | Axial |
| C42 | 1000 µF 10 V | Axial |
Designators are Console5's; Recap-a-Mac's annotated photograph gives the same count of each value and shows the axial parts.[8][5] Recap-a-Mac notes that some IIfx boards used 25 V parts for the 470 µF positions, and a higher voltage rating in the same size is acceptable.[5] Apple published no capacitor list for this board. See Capacitor Failure Symptoms.
Troubleshooting
[edit | edit source]Selected entries from Apple's symptom charts for the II, IIx and IIfx, with the cures in Apple's order:[4]
| Symptom | Apple's cures, in order |
|---|---|
| Error chord at start-up | Check the SIMMs (replace NEC SIMMs dated 9052 or earlier); logic board |
| No power: black screen, fan off, LED off | Cables; monitor on its own wall socket; power cord; batteries; power supply; logic board |
| Clicking, chirping or thumping | Remove extra NuBus cards; power supply; logic board |
| Shuts down intermittently | Clear the side and top vents (thermal protection; recovers after 30-40 minutes); power cord; batteries; power supply; logic board |
| Crashes or locks up intermittently | System software version; known-good software; remove extra RAM and NuBus cards; logic board; SIMMs; power supply |
| Dark screen; audio, drive, fan and LED working | Monitor brightness; try the monitor on another Macintosh; monitor; video cable; move the video card to another slot; video card; SIMMs; logic board; power supply |
| Completely dark, fan off, LED off | Monitor on its own wall socket; batteries; power supply; logic board |
| Will not eject a disk | Switch off, then hold the mouse button down while switching on; floppy drive |
| Internal hard drive dead: no LED, no spin | Hard drive data cable off; drive power cable; check the +5 V and +12 V lines to the drive; drive; logic board |
| Works with internal or external SCSI device, not both; drive icon missing; data lost or corrupted | External device ID must not be 0 or 7; SCSI termination (see above); external terminator; the external device |
| No sound from speaker | Volume at 1 or above; reset PRAM; speaker; logic board |
Some faults are not hardware faults. A program that crashes only on the IIfx is usually one that touches the I/O hardware directly, or needs the Serial Switch set to "Compatibility".[6] A shutdown after long use may be the thermal protection, and the machine should run again after 30-40 minutes.[4] The fan speeding up after a card is added is normal.[2]
Maintenance notes
[edit | edit source]- Opening: remove the cover mounting screw, push in the tabs at the rear and lift the cover off back first. Do not tilt it more than 45 degrees, or it can damage the floppy drives. Before refitting, check that none of the sheet-metal tabs inside the cover are bent inward.[4]
- Battery work needs the cover and drive mount out. The drive mount comes out after disconnecting the floppy and hard drive cables and removing four screws.[4]
- Logic board: disconnect the drive, speaker and power supply cables, remove the programmer's switch if fitted, take out two screws, then lift the board from the front while pushing in each of the nine tabs.[4]
- Floppy drive: the 1.4 MB drive is a direct-drive mechanism with no belt; see Macintosh Floppy Drive Maintenance. Apple recommends dust shields on 1.4 MB drives, and the drive must be cleaned before one is fitted.[4]
- Hard drive: see Macintosh HDD Maintenance. The computer is SCSI ID 7 and the internal drive ID 0.[4]
Easter egg
[edit | edit source]Set the system date to 19 March 1990 and restart holding Command-Option-F-X. The same design-team photograph as the Macintosh IIci's appears.[9]
Documentation
[edit | edit source]- Macintosh II/IIx/IIfx Service Source: Apple's service manual.[4]
- Macintosh IIfx Special Options and Technical Information: Apple's owner's booklet, with the technical specifications, power figures and connector pinouts.[2]
- Apple Technical Note HW 9 Macintosh IIfx The Inside Story: Apple's developer note on the I/O processors and software compatibility.[6]
Related pages
[edit | edit source]- Macintosh II and Macintosh IIx, the same case with slower processors
- Macintosh IIci
- Macintosh Quadra 900
- Capacitor Failure Symptoms
- Recommended Tools
References
[edit | edit source]- ↑ 1.0 1.1 1.2 Apple Macintosh IIfx Specs, EveryMac—link(accessed 2026-09-30) Introduced 19 March 1990, discontinued 15 April 1992; US$8,970-10,970; model M5525, Gestalt ID 13; order numbers M5510LL/A (floppy only), M5515LL/A (80 MB), M5520LL/A (160 MB), M5523LL/A (A/UX) and M5524LL/A (parity RAM), all with 4 MB; unique 80 ns 64-pin SIMMs fitted in groups of four, 128 MB with eight 16 MB SIMMs; two 3.6 V lithium batteries; no external floppy port.
- ↑ 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 2.10 2.11 2.12 2.13 2.14 2.15 2.16 2.17 2.18 2.19 2.20 2.21 2.22 2.23 2.24 2.25 2.26 Apple Computer, Macintosh IIfx Special Options and Technical Information (1990), Apple part number 030-3910-A, File:Macintosh IIfx Special Options and Technical Information.pdf; see Macintosh IIfx Special Options and Technical Information. Booklet page numbers: advanced features pp. 2-3; system software p. 5; processor-direct slot and programmer's switch pp. 6-9; technical information pp. 13-21.
- ↑ 3.0 3.1 3.2 3.3 3.4 Mac IIfx, Low End Mac—link(accessed 2026-09-30) Code names; two 10 MHz 6502 I/O processors; ROM SIMM slot must hold a IIfx ROM; variable-speed fan in the power supply; "black" SCSI terminator; 3.6 V half-AA PRAM battery; Apple ended support and parts orders on 31 August 1998.
- ↑ 4.00 4.01 4.02 4.03 4.04 4.05 4.06 4.07 4.08 4.09 4.10 4.11 4.12 4.13 4.14 4.15 4.16 4.17 4.18 4.19 4.20 4.21 4.22 4.23 4.24 4.25 4.26 4.27 4.28 Apple Computer, Macintosh II/IIx/IIfx Service Source (1995), File:Macintosh ii.iix.iifx.pdf; see Macintosh II/IIx/IIfx Service Source. Page numbers are the PDF's: Specifications pp. 5-12; Symptom Charts pp. 15-31; Take Apart pp. 33-52; IIfx logic board upgrade pp. 56-57; Battery Verification pp. 69-70; Battery Replacement pp. 71-73; Macintosh IIfx SCSI Termination pp. 80-85; Exploded View p. 87.
- ↑ 5.0 5.1 5.2 5.3 5.4 Macintosh IIfx, Recap-a-Mac—link(accessed 2026-09-30) Annotated photograph of the logic board, hosted here as File:Mac IIfx Recap Guide.jpg: 14 × 47 µF 16 V surface-mount, 1 × 10 µF 16 V, 1 × 220 µF 16 V, 3 × 470 µF 16 V and 1 × 1000 µF 10 V axial. The board has two sets of pads at each surface-mount electrolytic position, one for an electrolytic and one for a tantalum; some boards used 25 V parts for the 470 µF.
- ↑ 6.0 6.1 6.2 6.3 6.4 6.5 Apple Computer, Macintosh Technical Note HW 9, "Macintosh IIfx: The Inside Story", Rich Collyer, April 1990, File:Apple Technical Note HW 9 Macintosh IIfx The Inside Story.pdf; see Apple Technical Note HW 9 Macintosh IIfx The Inside Story. Sections ADB, CD-ROM Driver, EtherTalk Driver, MacsBug, NuBus, SCC, IIfx Serial Switch cdev, vSync Bit, SCSI, SWIM and VIA2 (pp. 1-5).
- ↑ Apple Computer, Guide to the Macintosh Family Hardware, second edition (Addison-Wesley, 1990), pp. 262–263, Table 6-23 (power supply output limits for the Macintosh II, Macintosh IIx and Macintosh IIfx). Hosted as File:Apple Guide to the Macintosh Family Hardware 2nd Edition 1990.pdf.
- ↑ 8.0 8.1 Macintosh IIfx, Console5 TechWiki—link(accessed 2026-09-30) Cap list for 820-0282-B: two builds, one with aluminium electrolytic SMD capacitors at C9 and C24 only, one with them at all positions; full list C5, C9, C10, C21-C24, C38, C43, C44, C48, C54, C57 and one unnumbered position near C3/C5 at 47 µF 16 V; C27 10 µF 16 V; C42 1000 µF 10 V; C221, C223, C224 470 µF 16 V; C226 220 µF 16 V.
- ↑ Hidden messages: An Apple Easter egg hunt– Benj Edwards, Macworld, 2013-03-30—link(accessed 2026-09-30)