Macintosh SE

Macintosh SE

Macintosh SE with an Apple Extended Keyboard
Specifications
Manufacturer	Apple Computer, Inc.
Type	Personal computer
Released	2 March 1987
Discontinued	1 August 1989 (SE FDHD: 15 October 1990)
Intro price	US$2,900 (dual floppy), US$3,700 (20 MB hard disk)
CPU	Motorola 68000 at 7.8336 MHz
Memory	1 or 2 MB, expandable to 4 MB (30-pin SIMMs, 150 ns or faster)
Storage	800 KB floppy (1.4 MB on the SE FDHD); optional 20 or 40 MB internal SCSI hard disk
Display	9-inch monochrome CRT, 512 × 342 pixels
Sound	Four-voice, 8-bit D/A conversion, 22 kHz sampling
ROM	256 KB
Ports / interface	2 × ADB; DB-19 external floppy; DB-25 SCSI; 2 × RS-232/RS-422 serial (mini-DIN-8); sound out
Expansion	Macintosh SE expansion slot (68000 PDS), 96-pin Euro-DIN
Power	90–140 V AC or 170–270 V AC, 47–63 Hz, 100 W maximum
Dimensions	13.6 × 9.6 × 10.9 in (34.5 × 24.4 × 27.6 cm)
Weight	17–21 lb (7.7–9.5 kg) depending on drives fitted
OS / Firmware	System 4.1 – System 7.5.5
Predecessor	Macintosh Plus
Successor	Macintosh SE/30, Macintosh Classic
Codename	Plus Plus, Maui, Aladdin, Chablis, Freeport
Model no.	M5010 (SE), M5011 (SE FDHD)

The Macintosh SE is a compact Macintosh introduced by Apple on 2 March 1987, the same day as the Macintosh II. It was the first compact Macintosh with an internal expansion slot and the first with a cooling fan, and its second drive bay takes either another floppy drive or an internal SCSI hard disk. Its keyboard and mouse connect through two Apple Desktop Bus ports.

Models

• The original SE shipped with one or two 800 KB floppy drives, or one floppy drive and a 20 or 40 MB hard disk. Low End Mac gives the launch prices as US$2,900 for the dual-floppy machine and US$3,700 with a 20 MB hard disk; EveryMac gives US$3,900 for the hard-disk model.
• The Macintosh SE FDHD replaced it on 1 August 1989. It has the 1.4 MB high-density drive, the SWIM disk controller in place of the IWM, and new ROMs to match. Apple's hardware guide dates the change to machines made from September 1989.

Apple's service manual tells the two apart by the disk controller: a chip with Apple part number 344-0062 is the SWIM; anything else is an IWM. An 800 KB SE could be upgraded with a kit containing the SWIM, two ROMs (342-0701 high, 342-0702 low) and the 1.4 MB drive. The mechanics of that upgrade are on the SE FDHD page.

Specifications

Macintosh SE: Apple's specifications

Item	Specification
CPU	Motorola 68000, 7.83 MHz
RAM	1 or 2 MB, expandable to 4 MB
ROM	256 KB
PRAM	256 bytes, in a CMOS custom chip with a seven-year lithium battery
Floppy	1.4 MB drive (this edition of the manual describes the FDHD); optional second internal and external drives
Hard disk	Optional 20 or 40 MB internal, or external
Expansion	Macintosh SE expansion slot, 96-pin Euro-DIN
SCSI	50-pin internal, DB-25 external
ADB	Two ports
Serial	Two RS-232/RS-422 ports, 230.4 kbaud maximum, mini-DIN-8
Sound	Four-voice, 8-bit D/A conversion, 22 kHz sampling rate
Video	9-inch diagonal, 512 × 342 bit-mapped
Line voltage	90–140 V AC; 170–270 V AC
Frequency	47–63 Hz
Maximum power	100 W
Dimensions	13.6 × 9.6 × 10.9 in (34.5 × 24.4 × 27.6 cm)
Weight	17–21 lb (7.7–9.5 kg), depending on whether a hard disk or second floppy drive is fitted

The system clock is 7.8336 MHz.

Hardware

Logic board

The logic board carries the MC68000, the BBU (Bob Bailey Unit) custom chip for address decoding and control, a GLU programmable logic array that supplements it, a Sony analogue sound IC, a VIA for ADB and the real-time clock, an 8530 SCC for the two serial ports, a 5380 SCSI controller, and the IWM or SWIM floppy controller. RAM is on four 30-pin SIMMs; see Macintosh SE Memory Upgrade Guide.

Apple's exchange boards are 661-0526 and 661-0536. A machine whose PRAM battery sits in a holder takes 661-0536. A machine with a soldered battery takes 661-0526; if its controller is a SWIM, the customer's SWIM and ROMs move to the replacement board, otherwise the 1.4 MB drive cannot use high-density disks. The exploded view in the same manual lists the logic board as 661-0530. Larry Pina identifies the bare boards as 820-0176 (the original) and 820-0250 (the "DIP SIMM" board), and gives SIMM positions separately for each.

Analogue board, power supply and video board

The SE does not use the combined power/sweep board of the Macintosh Plus. Behind the CRT are three separate modules: the analogue board (sweep, CRT drive and the brightness control), a power supply module screwed to it, and a video board on the neck of the CRT. Apple removes and replaces each one separately; its part numbers are 661-0371 (analogue board), 661-0370 (power supply) and 982-0024 (video board), the same numbers as in the SE/30.

The supply accepts 85–135 V or 170–270 V AC without being reconfigured and produces +5 V, +12 V (separate sweep and disk outputs) and −12 V; a regulator on the analogue board makes −5 V. Apple's output limits for the SE and SE/30 supply are:

Power supply output limits, Macintosh SE and SE/30

Output	Limits	Maximum load
+5 V	4.85–5.20 V	6.0 A
+12 V sweep	11.50–12.50 V	1.25 A
+12 V disk	11.50–12.80 V	2.1 A (4.0 A peak)
−12 V	−13.20 to −10.80 V	0.5 A

The +12 V disk rail may drop to 11.0 V during the 15-second peak load. There is no voltage-adjustment control on the SE: Apple's Adjustments chapter covers the yoke and the video controls only. The R56 trimmer in Apple's Macintosh Plus procedure is the single voltage-adjust control of the 128K/512K/Plus power/sweep board, where it moves +5 V and +12 V together; the SE does not have that board.

Two schematics of the analogue board are hosted here. File:Classic Analog Board Schematic.pdf is Apple's drawing; despite its file name, its internal title is "SE30_Analog_Board" and it shows the separate supply, the yoke, video-board, logic-board and hard-disk connectors of the SE and SE/30 board. File:Fan, CRT Board.jpg is a hand-drawn BOMARC Services schematic (1988) of the analogue board of the M5010 Macintosh SE, marked 820-0206-B / 630-0174-C, with its fan board and CRT socket board (820-0207-A / 630-0169).

Known faults

The component-level faults of the SE analogue board are documented by Larry Pina; the main ones are summarised below and covered in full on Macintosh SE Troubleshooting and Macintosh SE Capacitor Replacement Guide.

• Early SEs can show a herringbone pattern across the screen. Pina's fix is to replace flyback transformer T2, Apple part 157-0042A, with the later 157-0042C (p. 145).
• Early SEs have a loud crossflow fan (B1) that can make the display jitter; Pina replaces it with a brushless 12 V DC fan (p. 146). Apple's own replacement axial fan must only be fitted with the later, vertically mounted video board, because it does not leave enough vibration clearance for the old horizontal one.
• A shorted rectifier at CR2 gives no startup sound, a dark screen and a hissing or sizzling noise; a shorted CR3, often with a burnt horizontal output transistor Q2, gives a dead machine with no noise (pp. 147–148).
• A single vertical line, or poor horizontal linearity, points at the non-polarised capacitor C15 in the horizontal circuit (pp. 159–161).
• Some SE chassis have tabs that foul third-party expansion cards. Apple's fix is to bend the rearmost tab flush with the side panel.

The SE takes eight-chip SIMMs; a nine-chip module works, but the ninth chip is not connected.

Service manual and schematics

Apple service manual

Apple's Macintosh SE Service Source is described on Macintosh SE Service Source; the rest of the collection is in Category:Apple Service Source.

Board images

Macintosh SE boards

Logic board	Analogue board
Macintosh SE logic board Macintosh SE logic board schematic	Analogue board with its power supply and video board (the SE and SE/30 share these modules) BOMARC schematic of the Macintosh SE analogue board 820-0206-B, sheet 1, with the CRT socket board drawn at its edge

Maintenance, capacitors and troubleshooting

• Macintosh SE General Maintenance: cleaning, the PRAM battery and its 2.8 V threshold, rail checks and adjustments.
• Macintosh SE Capacitor Replacement Guide: logic board, analogue board and power supply lists.
• Macintosh SE Troubleshooting: Apple's symptom charts and Pina's component-level faults.
• Macintosh SE Memory Upgrade Guide
• CRT Discharge Procedure: read this before opening the case.
• Retrobrite, for a yellowed case.

Related pages

• Macintosh Plus, its predecessor
• Macintosh SE FDHD
• Macintosh SE/30, the 68030 machine in the same case
• Macintosh Classic, the low-cost replacement
• Apple Desktop Bus
• Sad Mac Error Codes and the Sad Mac Decoder