Macintosh IIsi: Difference between revisions
Verify against Apple's Macintosh IIsi Service Source (hosted, already cited at the foot of this page): maximum power is Apple's 100 W, not the '160 W Sony power supply' the body of the page claimed; RAM is 2 MB standard (1 MB soldered plus a SIMM) expandable to 17 MB; hard drive is 40 MB with an optional 80 MB, not 40/80/160; added Apple's replace-below-3.0 V battery threshold - the IIsi is 3.0 V, not the 2.8 V often applied to it from the IIcx/IIci - and the 68030's 256-byte caches and burst... |
Rewrite from IIsi Service Source and Developer Note: memory/video, ROM, slot and FPU, soft power, battery 3.0 V, part numbers; Apple spec sheet 160 W alongside the 100 W Service Source figure; remove uncited and Wikipedia-only claims |
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{{Infobox computer | {{Infobox computer | ||
| name = Macintosh IIsi | | name = Macintosh IIsi | ||
| image = [[File:Macintosh IIsi.jpg|250px]] | | image = [[File:Macintosh IIsi.jpg|250px|frameless]] | ||
| caption = Macintosh IIsi | | caption = Macintosh IIsi (All About Apple museum) | ||
| manufacturer = Apple Computer, Inc. | | manufacturer = Apple Computer, Inc. | ||
| type = Desktop | | type = Desktop personal computer | ||
| | | released = 15 October 1990 | ||
| discontinued = March | | discontinued = 15 March 1993 | ||
| price = US | | price = US$3,770-4,570 at introduction | ||
| cpu = Motorola 68030 | | cpu = Motorola 68030 at 20 MHz | ||
| memory = | | fpu = Optional 68882 on the slot adapter card | ||
| storage = Internal 40 MB SCSI hard drive; | | memory = 1 MB soldered plus four 30-pin SIMM sockets; 17 MB in Apple's specification, 65 MB with 16 MB SIMMs | ||
| | | rom = 512 KB | ||
| sound = | | storage = Internal 40 or 80 MB SCSI hard drive | ||
| dimensions = 4.0 | | media = Internal 1.4 MB floppy drive; external floppy port | ||
| weight = 10 | | graphics = Built in (DB-15), frame buffer in the soldered 1 MB of RAM | ||
| os = System 6.0.7 | | sound = Apple Sound Chip stereo output; 8-bit mono sound input | ||
| expansion = One 120-pin slot, NuBus or 68030 direct slot through an adapter card | |||
| ports = ADB, two RS-232/RS-422 serial (mini DIN-8), SCSI (DB-25), floppy (DB-19), video (DB-15), sound in and out | |||
| power = 100-240 V AC auto-configured, 50-60 Hz, 100 W maximum | |||
| dimensions = 4.0 × 12.4 × 14.9 in (10 × 31 × 37.2 cm) | |||
| weight = 10 lb (4.5 kg) | |||
| os = System 6.0.7 to Mac OS 7.6.1 | |||
| successor = [[Macintosh Centris 610]] | | successor = [[Macintosh Centris 610]] | ||
| codename = Erickson, Raffica, Ray Ban, Spin, Oceanic | | codename = Erickson, Raffica, Raffika, Ray Ban, Spin, Oceanic | ||
| model = M0360 | | model = M0360 (Gestalt ID 18) | ||
}} | }} | ||
The '''Macintosh IIsi''' is a desktop | The '''Macintosh IIsi''' is a desktop Macintosh introduced by Apple on 15 October 1990 and discontinued on 15 March 1993.<ref name="everymac">{{cite web |url=https://everymac.com/systems/apple/mac_ii/specs/mac_iisi.html |title=Apple Macintosh IIsi Specs |publisher=EveryMac |access-date=2026-09-30}} Introduced 15 October 1990, discontinued 15 March 1993; US$3,770 and US$4,570; model M0360, Gestalt ID 18; order numbers M0363LL/A (2 MB, 40 MB), M0364LL/A and M0364LL/B (5 MB, 80 MB), M0491LL/B (3 MB, 40 MB), M0954LL/A (5 MB, 160 MB); 64-320K of RAM used by video; 3.6 V lithium battery.</ref> It is a lower-cost relative of the [[Macintosh IIci]] in a smaller case of its own: the same MDU and RBV chip set, a 20 MHz 68030, 1 MB of RAM soldered to the board, built-in video and sound input, and a single expansion connector that takes either a NuBus card or a 68030 direct-slot card through an adapter.<ref name="dn">Apple Computer, ''Macintosh IIsi Computer Developer Note'' (1990), [[:File:Macintosh IIsi Developer Note.pdf]]; see [[Macintosh IIsi Developer Note]]. Page numbers are the PDF's: features pp. 14-16; compatibility pp. 18-20; RAM interface and video use of RAM pp. 32-36; ROM interface p. 38; on-board video p. 41; sound p. 61; ADB microcontroller, RTC, soft power, reset and NMI pp. 62-66; 68030 Direct Slot pp. 70-72; NuBus adapter p. 95.</ref> Apple's service manual gives it a volume of its own.<ref name="ss">Apple Computer, ''Macintosh IIsi'' Service Source (1995), [[:File:Macintosh iisi.pdf]]; see [[Macintosh IIsi Service Source]]. Page numbers are the PDF's: Specifications pp. 5-12; Symptom Charts pp. 15-28; Take Apart pp. 30-48; Upgrades (adapter cards) pp. 50-56; Battery Verification p. 59; Battery Replacement pp. 60-62; Exploded View p. 64.</ref> | ||
== Specifications == | |||
<templatestyles src="Template:StyledTable/styles.css" /> | <templatestyles src="Template:StyledTable/styles.css" /> | ||
{| class="wikitable styled-table" style="width:88%;" | |||
|+'''Macintosh IIsi specifications (Apple)''' | |||
{| class="wikitable styled-table" style="width: | ! Item !! Specification | ||
! | |||
|- | |- | ||
| | | Processor || Motorola 68030 at 20 MHz; 256-byte instruction and data caches; burst-mode RAM access; built-in MMU<ref name="ss" /> | ||
|- | |- | ||
| | | Coprocessor || Motorola 68882 at 20 MHz, on the optional adapter card only<ref name="ss" /> | ||
|- | |- | ||
| | | RAM || 2 MB, expandable to 17 MB (1 MB soldered plus four 30-pin SIMMs); 100 ns fast-page-mode<ref name="ss" /><ref name="dn" /> | ||
|- | |- | ||
| | | ROM || 512K<ref name="ss" /> | ||
|- | |- | ||
| | | Parameter RAM || 256 bytes<ref name="ss" /> | ||
|- | |- | ||
| | | Floppy drive || Internal 1.4 MB; external DB-19 port for an 800K or 1.4 MB drive<ref name="ss" /><ref name="dn" /> | ||
|- | |- | ||
| | | Hard drive || Internal 40 MB; optional internal 80 MB<ref name="ss" /> | ||
|- | |- | ||
| | | Expansion || One slot for either a NuBus or an 030 direct-slot card; 15 W maximum<ref name="ss" /> | ||
|- | |- | ||
| | | Video || Built-in: 12-inch and 13-inch RGB and 12-inch monochrome monitors at up to 8 bits per pixel; 15-inch portrait monitor at up to 4 bits per pixel<ref name="dn" /> | ||
|- | |- | ||
| | | Sound || Four-voice wavetable synthesis and stereo sampling; output impedance 8-600 Ω, short-circuit protected; internal speaker disabled when the jack is used; 8-bit mono sound input<ref name="ss" /><ref name="dn" /> | ||
|- | |- | ||
| | | Power || 100-240 V AC, automatically configured; 50-60 Hz single phase; 100 W maximum, not including the monitor<ref name="ss" /> | ||
|- | |- | ||
| | | Size and weight || 4.0 × 12.4 × 14.9 in (10 × 31 × 37.2 cm); 10 lb (4.5 kg), varying with configuration<ref name="ss" /> | ||
|} | |} | ||
=== | Apple's online specification sheet for the IIsi gives the maximum as 160 W (1.33 A, 547.2 BTU per hour), the battery as 3.6 V lithium, and one ADB port.<ref name="applespecs">{{cite web |url=https://support.apple.com/en-us/112193 |title=Macintosh IIsi: Technical Specifications |publisher=Apple |access-date=2026-09-30}} Max watts 160, amps 1.33, BTU per hour 547.2, 100-240 V, 50-60 Hz; battery 3.6 V lithium; soft power and pass-through outlet; 1 MB on the logic board, four 30-pin SIMM slots, 1-17 MB, 100 ns, installed in groups of four; one ADB port; Gestalt ID 18; ROM ID $067C; original system software 6.0.7; supported to 7.6.1.</ref> | ||
{| class="wikitable styled-table" style="width: | |||
|+ '''Macintosh IIsi | {| class="wikitable styled-table" style="width:70%; text-align:center;" | ||
! Order | |+'''Macintosh IIsi order numbers (EveryMac)''' | ||
! Order number !! RAM !! Hard drive | |||
|- | |- | ||
| M0363LL/A || 2 MB || 40 MB | | M0363LL/A || 2 MB || 40 MB | ||
|- | |- | ||
| | | M0491LL/B || 3 MB || 40 MB | ||
|- | |- | ||
| M0364LL/B || 5 MB || 80 MB | | M0364LL/A, M0364LL/B || 5 MB || 80 MB | ||
|- | |- | ||
| M0954LL/A || 5 MB || 160 MB | |||
| M0954LL/A || 5 MB || 160 MB | |||
|} | |} | ||
=== | == Hardware == | ||
{| | === Memory and video === | ||
Bank A is the 1 MB soldered to the logic board, eight 256K × 4 DRAMs that cannot be changed. Bank B is four 30-pin SIMM sockets, filled with four identical SIMMs of 256K, 512K, 1 MB, 2 MB or 4 MB. Apple's developer note also allows 16 MB SIMMs, which give 65 MB.<ref name="dn" /><ref name="applespecs" /> Apple's figure for SIMM speed is 100 ns or faster.<ref name="dn" /> | |||
The built-in video has no video RAM of its own. The RBV chip uses the soldered bank A as its frame buffer, taking only as much as the screen needs at the chosen depth.<ref name="dn" /> EveryMac gives 64K to 320K.<ref name="everymac" /> Video fetches tie up bank A only; the processor can use bank B at the same time.<ref name="dn" /> Low End Mac notes that sharing RAM with the video slows the machine slightly, and suggests a 768K disk cache, which occupies bank A so that programs run from the SIMMs.<ref name="lem">{{cite web |url=https://lowendmac.com/1990/mac-iisi/ |title=Mac IIsi |publisher=Low End Mac |access-date=2026-09-30}} Intended as a 25 MHz machine and scaled back to 20 MHz; 768K disk cache or IIsi-RAM-Muncher to keep programs out of the video bank; speaker fault from poor contact; ROM SIMM rare, and a IIsi that has one will not work without it; US$3,800; code names; SE/30 PDS at 20 MHz.</ref> With an unknown monitor, or none, the built-in video stops.<ref name="dn" /> | |||
| | |||
|- | === ROM === | ||
| | Apple's developer note says the first production IIsi boards carry the 512K ROM on a ROM SIMM, and later boards have it soldered, with the SIMM socket kept for upgrades.<ref name="dn" /> Low End Mac says a board built with a ROM SIMM will not work without it.<ref name="lem" /> On the board Recap-a-Mac photographed, the soldered ROMs are the two square chips above the floppy connector.<ref name="ram">{{cite web |url=https://recapamac.com.au/macintosh-iisi/ |title=Macintosh IIsi |publisher=Recap-a-Mac |access-date=2026-09-30}} Annotated photograph of logic board 820-0301-A, hosted here as [[:File:Mac IIsi Recap Guide.jpg]]: 11 × 47 µF 16 V surface-mount and 2 × 220 µF 16 V axial; leaky capacitors on the logic board and in the power supply; some versions use a ROM SIMM instead of soldered ROMs.</ref> | ||
|- | |||
| | === Expansion slot and FPU === | ||
|} | The logic board has one 120-pin Euro-DIN connector. Apple sold two adapter cards for it: one takes a 68030 direct-slot card, the other a NuBus card, and both carry a 20 MHz 68882. A IIsi without an adapter has no FPU; a buyer who wanted the FPU and nothing else still had to fit an adapter.<ref name="dn" /><ref name="ss" /> Macintosh SE/30 direct-slot cards work if they can run at the IIsi's 20 MHz and their ribbon cables are at least 220 mm long.<ref name="dn" /> The NuBus card sits horizontally over the logic board at slot address $9, and Apple says any NuBus card size it specifies fits.<ref name="dn" /> | ||
Apple budgets 15 W for the slot. The Service Source prints the currents as "+5 V 2.0 A, +12 V 175 A, -12 V 150 A"; the last two can only be milliamps within 15 W.<ref name="ss" /> | |||
=== Power control === | |||
A Motorola 68HC05-based microcontroller runs ADB, the clock, parameter RAM, soft power and power-on reset. The supply keeps a +5 V trickle output whenever the machine is plugged in, which lets the controller watch the keyboard power key and the rear power switch.<ref name="dn" /> There is no programmer's switch: Command-Control-Power gives a hard reset, and Command-Power an NMI once a control panel has enabled it; hold either for at least a second.<ref name="dn" /> | |||
The rear power switch can be locked on with a screwdriver or coin, so that the IIsi restarts itself after a power cut. Apple's cure for "system restarts itself" is to turn that switch back to the unlocked, horizontal position.<ref name="dn" /><ref name="ss" /> | |||
=== Sound === | |||
Sound output uses the Apple Sound Chip and two Sony sound chips, as on the II, IIx, IIcx and IIci. Sound input is 8-bit mono through a filter, preamplifier and FIFO buffer; a microphone came with the machine.<ref name="dn" /> The speaker sits under the logic board and connects through metal fingers pressing against the underside of the board.<ref name="ss" /> When those contacts corrode, the internal speaker cuts out, sometimes only after hours of running; see [[Macintosh IIsi Troubleshooting]].<ref name="faq">Elliotte Rusty Harold and contributors, Macintosh hardware FAQ, "How can I fix the sound on my IIsi?", {{cite web |url=https://stason.org/TULARC/os-macintosh/hardware/32-How-can-I-fix-the-sound-on-my-IISI-Macintosh-hardware.html |title=32 How can I fix the sound on my IISI? |publisher=TULARC |access-date=2026-09-30}}</ref> | |||
=== Power supply === | |||
Apple part 661-1616.<ref name="ss" /> Console5 and Recap-a-Mac identify it as a Sony APS-06M, and Recap-a-Mac says it is "extremely prone to leakage".<ref name="c5psu">{{cite web |url=https://wiki.console5.com/wiki/Sony_APS-06M |title=Sony APS-06M |publisher=Console5 TechWiki |access-date=2026-09-30}}</ref><ref name="rampsu">{{cite web |url=https://recapamac.com.au/macintosh-iisi-power-supply/ |title=Macintosh IIsi Power Supply |publisher=Recap-a-Mac |access-date=2026-09-30}}</ref> Its capacitor list is on the [[Macintosh IIsi Capacitor Replacement Guide]]. Apple publishes no rail tolerances and no adjustment for it; every power fault in the symptom charts ends at "replace power supply".<ref name="ss" /> | |||
=== Battery === | |||
The clock and parameter RAM are kept by a 3.6 V lithium cell in a holder on the logic board.<ref name="applespecs" /> Apple's test: with the cover off, measure on the 10 V DC range and replace the battery if it reads below 3.0 V. To change it, remove the cover and expansion card, prise open the latch at the end of the holder with a small flat-blade screwdriver, and match the "+" end to the "+" on the holder.<ref name="ss" /> Remove the cell before storing the machine; see [[Battery Explosion, Capacitor or Corrosion Damage]]. | |||
== | === Capacitors === | ||
Logic board 820-0301-A has eleven 47 µF 16 V surface-mount electrolytics and two 220 µF 16 V axial parts, and Recap-a-Mac found leaking capacitors on both the logic board and the power supply.<ref name="ram" /> Designators and the power supply list are on the [[Macintosh IIsi Capacitor Replacement Guide]]. | |||
== Maintenance and repair == | |||
* [[Macintosh IIsi General Maintenance]]: opening the case, battery, power supply and cleaning. | |||
* [[Macintosh IIsi Troubleshooting]]: Apple's symptom charts and the known faults. | |||
* [[Macintosh IIsi Capacitor Replacement Guide]]: logic board and power supply capacitor lists. | |||
== Documentation == | |||
" | * [[Macintosh IIsi Service Source]]: Apple's service manual.<ref name="ss" /> | ||
* [[Macintosh IIsi Developer Note]]: Apple's developer note, with the memory, video, power control and expansion details.<ref name="dn" /> | |||
[[Macintosh | |||
== | <pdf width="800" height="500">File:Macintosh_iisi.pdf</pdf> | ||
== Related pages == | |||
* [[Macintosh IIci]] | * [[Macintosh IIci]] | ||
* [[Macintosh LC]] | * [[Macintosh LC]], introduced the same day | ||
* [[Macintosh SE/30]] | * [[Macintosh SE/30]], whose direct-slot cards fit the IIsi adapter | ||
* [[Macintosh Centris 610]] | * [[Macintosh Centris 610]] | ||
* [[Sad Mac Error Codes]] | |||
== References == | == References == | ||
<references /> | <references /> | ||
{{Navbox-AppleVintage|state=collapsed}} | |||
[[Category:Apple Vintage Computers]] | [[Category:Apple Vintage Computers]] | ||
[[Category:Macintosh II series]] | [[Category:Macintosh II series]] | ||
Latest revision as of 15:56, 30 September 2026
 | |
| Macintosh IIsi (All About Apple museum) | |
| Specifications | |
|---|---|
| Manufacturer | Apple Computer, Inc. |
| Type | Desktop personal computer |
| Released | 15 October 1990 |
| Discontinued | 15 March 1993 |
| Intro price | US$3,770-4,570 at introduction |
| CPU | Motorola 68030 at 20 MHz |
| Memory | 1 MB soldered plus four 30-pin SIMM sockets; 17 MB in Apple's specification, 65 MB with 16 MB SIMMs |
| Storage | Internal 40 or 80 MB SCSI hard drive |
| Display | — |
| Sound | Apple Sound Chip stereo output; 8-bit mono sound input |
| Graphics | Built in (DB-15), frame buffer in the soldered 1 MB of RAM |
| ROM | 512 KB |
| FPU / coprocessor | Optional 68882 on the slot adapter card |
| Media | Internal 1.4 MB floppy drive; external floppy port |
| Ports / interface | ADB, two RS-232/RS-422 serial (mini DIN-8), SCSI (DB-25), floppy (DB-19), video (DB-15), sound in and out |
| Expansion | One 120-pin slot, NuBus or 68030 direct slot through an adapter card |
| Power | 100-240 V AC auto-configured, 50-60 Hz, 100 W maximum |
| Dimensions | 4.0 × 12.4 × 14.9 in (10 × 31 × 37.2 cm) |
| Weight | 10 lb (4.5 kg) |
| OS / Firmware | System 6.0.7 to Mac OS 7.6.1 |
| Successor | Macintosh Centris 610 |
| Codename | Erickson, Raffica, Raffika, Ray Ban, Spin, Oceanic |
| Model no. | M0360 (Gestalt ID 18) |
The Macintosh IIsi is a desktop Macintosh introduced by Apple on 15 October 1990 and discontinued on 15 March 1993.[1] It is a lower-cost relative of the Macintosh IIci in a smaller case of its own: the same MDU and RBV chip set, a 20 MHz 68030, 1 MB of RAM soldered to the board, built-in video and sound input, and a single expansion connector that takes either a NuBus card or a 68030 direct-slot card through an adapter.[2] Apple's service manual gives it a volume of its own.[3]
Specifications
[edit | edit source]| Item | Specification |
|---|---|
| Processor | Motorola 68030 at 20 MHz; 256-byte instruction and data caches; burst-mode RAM access; built-in MMU[3] |
| Coprocessor | Motorola 68882 at 20 MHz, on the optional adapter card only[3] |
| RAM | 2 MB, expandable to 17 MB (1 MB soldered plus four 30-pin SIMMs); 100 ns fast-page-mode[3][2] |
| ROM | 512K[3] |
| Parameter RAM | 256 bytes[3] |
| Floppy drive | Internal 1.4 MB; external DB-19 port for an 800K or 1.4 MB drive[3][2] |
| Hard drive | Internal 40 MB; optional internal 80 MB[3] |
| Expansion | One slot for either a NuBus or an 030 direct-slot card; 15 W maximum[3] |
| Video | Built-in: 12-inch and 13-inch RGB and 12-inch monochrome monitors at up to 8 bits per pixel; 15-inch portrait monitor at up to 4 bits per pixel[2] |
| Sound | Four-voice wavetable synthesis and stereo sampling; output impedance 8-600 Ω, short-circuit protected; internal speaker disabled when the jack is used; 8-bit mono sound input[3][2] |
| Power | 100-240 V AC, automatically configured; 50-60 Hz single phase; 100 W maximum, not including the monitor[3] |
| Size and weight | 4.0 × 12.4 × 14.9 in (10 × 31 × 37.2 cm); 10 lb (4.5 kg), varying with configuration[3] |
Apple's online specification sheet for the IIsi gives the maximum as 160 W (1.33 A, 547.2 BTU per hour), the battery as 3.6 V lithium, and one ADB port.[4]
| Order number | RAM | Hard drive |
|---|---|---|
| M0363LL/A | 2 MB | 40 MB |
| M0491LL/B | 3 MB | 40 MB |
| M0364LL/A, M0364LL/B | 5 MB | 80 MB |
| M0954LL/A | 5 MB | 160 MB |
Hardware
[edit | edit source]Memory and video
[edit | edit source]Bank A is the 1 MB soldered to the logic board, eight 256K × 4 DRAMs that cannot be changed. Bank B is four 30-pin SIMM sockets, filled with four identical SIMMs of 256K, 512K, 1 MB, 2 MB or 4 MB. Apple's developer note also allows 16 MB SIMMs, which give 65 MB.[2][4] Apple's figure for SIMM speed is 100 ns or faster.[2]
The built-in video has no video RAM of its own. The RBV chip uses the soldered bank A as its frame buffer, taking only as much as the screen needs at the chosen depth.[2] EveryMac gives 64K to 320K.[1] Video fetches tie up bank A only; the processor can use bank B at the same time.[2] Low End Mac notes that sharing RAM with the video slows the machine slightly, and suggests a 768K disk cache, which occupies bank A so that programs run from the SIMMs.[5] With an unknown monitor, or none, the built-in video stops.[2]
ROM
[edit | edit source]Apple's developer note says the first production IIsi boards carry the 512K ROM on a ROM SIMM, and later boards have it soldered, with the SIMM socket kept for upgrades.[2] Low End Mac says a board built with a ROM SIMM will not work without it.[5] On the board Recap-a-Mac photographed, the soldered ROMs are the two square chips above the floppy connector.[6]
Expansion slot and FPU
[edit | edit source]The logic board has one 120-pin Euro-DIN connector. Apple sold two adapter cards for it: one takes a 68030 direct-slot card, the other a NuBus card, and both carry a 20 MHz 68882. A IIsi without an adapter has no FPU; a buyer who wanted the FPU and nothing else still had to fit an adapter.[2][3] Macintosh SE/30 direct-slot cards work if they can run at the IIsi's 20 MHz and their ribbon cables are at least 220 mm long.[2] The NuBus card sits horizontally over the logic board at slot address $9, and Apple says any NuBus card size it specifies fits.[2]
Apple budgets 15 W for the slot. The Service Source prints the currents as "+5 V 2.0 A, +12 V 175 A, -12 V 150 A"; the last two can only be milliamps within 15 W.[3]
Power control
[edit | edit source]A Motorola 68HC05-based microcontroller runs ADB, the clock, parameter RAM, soft power and power-on reset. The supply keeps a +5 V trickle output whenever the machine is plugged in, which lets the controller watch the keyboard power key and the rear power switch.[2] There is no programmer's switch: Command-Control-Power gives a hard reset, and Command-Power an NMI once a control panel has enabled it; hold either for at least a second.[2]
The rear power switch can be locked on with a screwdriver or coin, so that the IIsi restarts itself after a power cut. Apple's cure for "system restarts itself" is to turn that switch back to the unlocked, horizontal position.[2][3]
Sound
[edit | edit source]Sound output uses the Apple Sound Chip and two Sony sound chips, as on the II, IIx, IIcx and IIci. Sound input is 8-bit mono through a filter, preamplifier and FIFO buffer; a microphone came with the machine.[2] The speaker sits under the logic board and connects through metal fingers pressing against the underside of the board.[3] When those contacts corrode, the internal speaker cuts out, sometimes only after hours of running; see Macintosh IIsi Troubleshooting.[7]
Power supply
[edit | edit source]Apple part 661-1616.[3] Console5 and Recap-a-Mac identify it as a Sony APS-06M, and Recap-a-Mac says it is "extremely prone to leakage".[8][9] Its capacitor list is on the Macintosh IIsi Capacitor Replacement Guide. Apple publishes no rail tolerances and no adjustment for it; every power fault in the symptom charts ends at "replace power supply".[3]
Battery
[edit | edit source]The clock and parameter RAM are kept by a 3.6 V lithium cell in a holder on the logic board.[4] Apple's test: with the cover off, measure on the 10 V DC range and replace the battery if it reads below 3.0 V. To change it, remove the cover and expansion card, prise open the latch at the end of the holder with a small flat-blade screwdriver, and match the "+" end to the "+" on the holder.[3] Remove the cell before storing the machine; see Battery Explosion, Capacitor or Corrosion Damage.
Capacitors
[edit | edit source]Logic board 820-0301-A has eleven 47 µF 16 V surface-mount electrolytics and two 220 µF 16 V axial parts, and Recap-a-Mac found leaking capacitors on both the logic board and the power supply.[6] Designators and the power supply list are on the Macintosh IIsi Capacitor Replacement Guide.
Maintenance and repair
[edit | edit source]- Macintosh IIsi General Maintenance: opening the case, battery, power supply and cleaning.
- Macintosh IIsi Troubleshooting: Apple's symptom charts and the known faults.
- Macintosh IIsi Capacitor Replacement Guide: logic board and power supply capacitor lists.
Documentation
[edit | edit source]- Macintosh IIsi Service Source: Apple's service manual.[3]
- Macintosh IIsi Developer Note: Apple's developer note, with the memory, video, power control and expansion details.[2]
Related pages
[edit | edit source]- Macintosh IIci
- Macintosh LC, introduced the same day
- Macintosh SE/30, whose direct-slot cards fit the IIsi adapter
- Macintosh Centris 610
- Sad Mac Error Codes
References
[edit | edit source]- ↑ 1.0 1.1 Apple Macintosh IIsi Specs, EveryMac—link(accessed 2026-09-30) Introduced 15 October 1990, discontinued 15 March 1993; US$3,770 and US$4,570; model M0360, Gestalt ID 18; order numbers M0363LL/A (2 MB, 40 MB), M0364LL/A and M0364LL/B (5 MB, 80 MB), M0491LL/B (3 MB, 40 MB), M0954LL/A (5 MB, 160 MB); 64-320K of RAM used by video; 3.6 V lithium battery.
- ↑ 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 Apple Computer, Macintosh IIsi Computer Developer Note (1990), File:Macintosh IIsi Developer Note.pdf; see Macintosh IIsi Developer Note. Page numbers are the PDF's: features pp. 14-16; compatibility pp. 18-20; RAM interface and video use of RAM pp. 32-36; ROM interface p. 38; on-board video p. 41; sound p. 61; ADB microcontroller, RTC, soft power, reset and NMI pp. 62-66; 68030 Direct Slot pp. 70-72; NuBus adapter p. 95.
- ↑ 3.00 3.01 3.02 3.03 3.04 3.05 3.06 3.07 3.08 3.09 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18 3.19 Apple Computer, Macintosh IIsi Service Source (1995), File:Macintosh iisi.pdf; see Macintosh IIsi Service Source. Page numbers are the PDF's: Specifications pp. 5-12; Symptom Charts pp. 15-28; Take Apart pp. 30-48; Upgrades (adapter cards) pp. 50-56; Battery Verification p. 59; Battery Replacement pp. 60-62; Exploded View p. 64.
- ↑ 4.0 4.1 4.2 Macintosh IIsi: Technical Specifications, Apple—link(accessed 2026-09-30) Max watts 160, amps 1.33, BTU per hour 547.2, 100-240 V, 50-60 Hz; battery 3.6 V lithium; soft power and pass-through outlet; 1 MB on the logic board, four 30-pin SIMM slots, 1-17 MB, 100 ns, installed in groups of four; one ADB port; Gestalt ID 18; ROM ID $067C; original system software 6.0.7; supported to 7.6.1.
- ↑ 5.0 5.1 Mac IIsi, Low End Mac—link(accessed 2026-09-30) Intended as a 25 MHz machine and scaled back to 20 MHz; 768K disk cache or IIsi-RAM-Muncher to keep programs out of the video bank; speaker fault from poor contact; ROM SIMM rare, and a IIsi that has one will not work without it; US$3,800; code names; SE/30 PDS at 20 MHz.
- ↑ 6.0 6.1 Macintosh IIsi, Recap-a-Mac—link(accessed 2026-09-30) Annotated photograph of logic board 820-0301-A, hosted here as File:Mac IIsi Recap Guide.jpg: 11 × 47 µF 16 V surface-mount and 2 × 220 µF 16 V axial; leaky capacitors on the logic board and in the power supply; some versions use a ROM SIMM instead of soldered ROMs.
- ↑ Elliotte Rusty Harold and contributors, Macintosh hardware FAQ, "How can I fix the sound on my IIsi?", 32 How can I fix the sound on my IISI?, TULARC—link(accessed 2026-09-30)
- ↑ Sony APS-06M, Console5 TechWiki—link(accessed 2026-09-30)
- ↑ Macintosh IIsi Power Supply, Recap-a-Mac—link(accessed 2026-09-30)
