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Mac SE schematic diagrams

Logic board
Analog board 1   This analog board seems to be from an SE/30, but I don't think Apple changed a lot.
Analog board 2
Netzteil   Power supply?

Mac SE component diagram

An expanded view of the SE's components, with part numbers.

Mac SE and SE/30 external pinouts

May 1993

This page gives the pin assignments and functions for the connectors on the back panels of the Macintosh SE and SE/30. The pinouts are the same with the exception of the audio output ports. The Macintosh SE provides a monaural signal and the Macintosh SE/30 a stereo signal. Appropriate information appears below.

Apple Desktop Bus (ADB) 
Pin             Signal name     Signal description

1               ADB             Data 
2               NC              Reserved 
3               +5v             +5 volts DC 
4               GND             Signal ground

- Connector type: 4-pin minicircular 
- Total length of all cables not to exceed 16 feet (5 meters)

SCSI Port (25-pin) 
Pin             Signal name     Signal description

1               REQ/            Request 
2               MSG/            Message 
3               I/O/            Input/Output 
4               RST/            SCSI bus reset 
5               ACK/            Acknowledge 
6               BSY/            Busy 
7               GND             Signal ground 
8               DB0/            Data bit 0 
9               GND             Signal ground 
10              DB3/            Data bit 3 
11              DB5/            Data bit 5 
12              DB6/            Data bit 6 
13              DB7/            Data bit 7 
14              GND             Signal ground 
15              C/D/            Common/Data 
16              GND             Signal ground 
17              ATN/            Attention 
18              GND             Signal ground 
19              SEL/            Select 
20              DBP/            Data parity 
21              DB1/            Data bit 1 
22              DB2/            Data bit 2 
23              DB4/            Data bit 4 
24              GND             Signal ground 
25              TPWR            Terminator power

- Connector type: DB-25 
- Total length of all cables not to exceed 20 feet (6 meters)

WARNING: The SCSI port uses the same type of connector as a standard RS-232, 
DB-25 serial interface, but it is different electrically. Do not connect any 
RS-232 device to this connector. Doing so can result in damage to both the 
device and the Macintosh.

Modem and Printer Ports 
Pin             Signal name     Signal description

1               HSKo            Handshake out 
2               HSKi            Handshake in/external clock 
3               TXD-            Transmit data - 
4               GND             Signal ground 
5               RXD-            Receive data - 
6               TXD+            Transmit data + 
7               GPi             General purpose input* 
8               RXD+            Receive data +

*Modem port only. Can be set in software to be a second external clock. 
- Connector type: 8-pin minicircular

Disk Drive Port 
Pin             Signal name     Signal description 
1               GND             Signal ground 
2               GND             Signal ground 
3               GND             Signal ground 
4               GND             Signal ground 
5               -12v            -12 volts DC 
6               +5v             +5 volts DC 
7               +12v            +12 volts DC 
8               +12v            +12 volts DC 
9               NC              No connection 
1               PWM             Motor speed control 
11              PH0             Register select CA0 
12              PH1             Register select CA1 
13              PH2             Register select CA2 
14              PH3             Register write strobe LSTRB 
15              WRREQ/          Write request 
16              SEL             Register select line SEL 
17              ENBL/           Drive enable 
18              RD              Read data 
19              WR              Write data

- Connector type: DB-19

Audio Jack for the Macintosh SE 
Pin             Signal name     Signal description

(Sleeve)        GND             Signal ground 
(Tip)           AUDIO           .5 volt peak-to-peak audio signal

- Connector type: Miniature mono phone plug 
- The internal speaker is disabled when this port is in use.

Audio Jack for the Macintosh SE/30 
Pin             Signal name     Signal description 
(Sleeve)        GND             Signal ground 
(Ring)          RIGHT           .75 volt peak-to-peak audio signal, right channel 
(Tip)           LEFT            .75 volt peak-to-peak audio signal, left channel

- Connector type: Stereo miniature phone plug 
- The internal speaker is disabled when this port is in use.

Macintosh SE Internal System Expansion Slot: Pinout Information

          Column     Column        Column
          1          2             3 

32        -12V       -5V           +12V 
31        Spare      +12V          +12V 
30        Ground     +12V          Ground 
29        D15        Ground        C16M 
28        D14        Ext.STK/      C8M 
27        D13        Reserved      E 
26        D12        Reserved      A23 
25        D11        Reserved      A22 
24        D10        Reserved      A21 
23        D9         Reserved      A20 
22        D8         Spare         A19 
21        D7         BERR/         A18 
20        D6         IPL2/         A17 
19        D5         IPL1/         A16 
18        D4         IPL0/         A15 
17        D3         +5V           A14 
16        D2         +5V           A13 
15        D1         +5V           A12 
14        D0         +5V           A11 
13       +5V         +5V           A10 
12        RESET/     HALT/          A9 
11        PMCYC/     Reserved       A8 
10        AS/        Reserved       A7 
9         UDS/       Ground         A6 
8         LDS/       Ground         A5 
7         R/W/       Ground         A4 
6         DTACK/     Ground         A3 
5         BG/        Ground         A2 
4         BGACK/     Ground         A1 
3         BR/        Ground        FC0 
2         VMA/       Ground        FC1 
1         VPA/       Ground        FC2

Here is a description of the signals in the system expansion slot.

Signal        Description

FC0-FC2       68000 Function Code lines 
A1-A23        68000 Address lines 
E             68000 E Clock 
C8M           Microprocessor clock = 7.8336 MHz = C16M divided by 2. 
C16M          Gate Array Clock = 15.6672 MHz 
HALT/         68000 Halt. Wired directly to RESET/ 
IPL0/-IPL2/   68000 Interrupt Priority Level lines 
BERR/         68000 Bus Error.  Generated by gate array due to SCSI
                access timeout. 
Ext.DTK/      Pull low to put the gate array generated DTACK/ into a
                high-impedance state. The expansion board is then
                responsible for generating the DTACK/signal (as an output
                to the microprocessor, throught the DTACK/signal line). 
VPA/          68000 Valid Peripheral Address. Supplied to 68000.
                For Macintosh SE, VPA space is $E0 0000 to $FF FFFF. 
VMA/          68000 Valid Memory Address 
BR/           68000 Bus Request 
BGACK/        68000 Bus Grant Acknowledge 
BG/           68000 Bus Grant 
DTACK/        68000 Data Transfer Acknowledge. Inserts wait states until
                data bus is available. Normally supplied by the gate array.
                Gate array generation of DTACK/ can be suppressed (put into
                a high-impedance state) by pulling the EXT.DTACK/line low;
                this allows DTACK/ to be externally generated by an add-on
                device. DTACK/ is not supplied for accesses to VPA space,
                is held off to separate 2 successive accesses to the SCC and
                is held off during RAM access by video. 
R/W/          68000 Read/Write 
LDS/          68000 Lower Data Strobe 
UDS/          68000 Upper Data Strobe 
AS/           68000 Address Strobe 
PMCYC/        Processor-Memory Cycle. Used to synchronize with the gate
                array for RAM accesses. PMCYC/ is low when RAM is available
                for microporcessor accesses and is high during video acesses.
                PMCYC/ is always high during SO. 
RESET/        68000 Reset. Wired directly to HALT/. 
D0-D15        68000 Data Bus

Additional information may be found in the the Motorola 68000 manual.

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