Macintosh SE Troubleshooting
Fault-finding for the Macintosh SE and Macintosh SE FDHD, from two sources: Apple's symptom charts in the Macintosh SE Service Source, which work down to the module (logic board, analogue board, power supply, video board, CRT), and Larry Pina's The Dead Mac Scrolls, which goes down to the component. Apple lists its cures in order of likelihood: try the first, and if you swap a module that does not cure the fault, refit the original before moving to the next cure.[1][2]
The SE has a CRT, an analogue board at high voltage and a mains power supply. Read CRT Discharge Procedure before opening it, and do not wear a wriststrap until the CRT is discharged.[1]
First checks
[edit | edit source]- Measure the supply rails. Apple's limits for the SE and SE/30 supply are +5 V 4.85–5.20 V, +12 V sweep 11.50–12.50 V, +12 V disk 11.50–12.80 V and −12 V −13.20 to −10.80 V.[3] At the logic board connector J12, +5 V is on pins 12 and 13, +12 V on pin 14, −12 V on pin 7 and −5 V on pin 6; pins 1–5 and 8 are ground.[3] There is no voltage adjustment on the SE; the R56 trimmer in Apple's Macintosh Plus procedure belongs only to the 128K/512K/Plus power/sweep board, where it is the single control that moves +5 V and +12 V together.
- Check the PRAM battery: below 2.8 V, replace it.[1] See Macintosh SE General Maintenance#PRAM battery.
- Disconnect external SCSI devices and remove any PDS card.
- Reseat the cable at J12. Apple's first cure for clicking, chirping or thumping is to check that the analogue board cable is connected there.[1]
Apple's symptom charts
[edit | edit source]| Symptom | Apple's cures, in order |
|---|---|
| Screen dark; sound and drive work | Turn brightness clockwise; check video cable connections; analogue board; video board; logic board; CRT |
| Screen bright, sound present, no picture information | Analogue board; video board; logic board |
| Screen completely dark and fan not running | Power supply; analogue board |
| Single vertical line | Analogue board; video board; logic board; CRT |
| Single horizontal line | Analogue board; video board; logic board; CRT |
| Vertical or horizontal bars or stripes | Logic board; analogue board |
| White dot in the centre of the screen | Check the yoke cable is connected; analogue board; CRT |
| Screen jitters at top left and/or lower right | Analogue board |
| Clicking, chirping or thumping | Check the analogue board cable at J12 on the logic board; power supply; analogue board; logic board |
| Smoke or smell | Power supply; analogue board |
| No video, no sound, no drive activity | Power cord connected and switched on; power cord; power supply; analogue board; logic board |
| Sad Mac icon | Bad disk; SIMMs, if the code matches Apple's faulty-SIMM codes; check the three-pin memory jumper; logic board |
| Sad Mac with a black vertical line and a screeching sound | Check the three-pin memory jumper; logic board |
| One internal floppy drive does not work | Bad disk; drive data cable; drive; logic board |
| Neither internal floppy drive works | Bad disk; logic board |
| External floppy drive does not work | Bad disk; external drive; logic board |
| Disk ejects and a blinking "X" icon appears | Known-good system disk; floppy drive; logic board |
| Disk will not go in, or will not eject | Paper clip in the hole beside the drive; hold the mouse button down while switching on; floppy drive |
| Internal floppy drive runs continuously | Bad disk; floppy drive; logic board; drive data cable |
| Hard disk does not work | Check no SCSI loopback card is fitted; hard disk data cable; hard disk; logic board |
| Internal or external SCSI works, but not both | External device ID; external terminator; check the internal drive is terminated; hard disk select cable |
| Cursor does not move | Mouse connection; clean the mouse; move the mouse from the keyboard to an ADB port (if it then works, replace the keyboard); mouse; logic board |
| No response to the keyboard | Keyboard connection; keyboard cable; keyboard; logic board |
| Double-click does not open items | Remove extra System files; clear PRAM; as for the cursor |
Clearing PRAM: under System 7, hold Command-Option-P-R during startup, before "Welcome to Macintosh" appears; under System 6, hold Command-Option-Shift and choose the Control Panel from the Apple menu.[1]
The SE service manual prints "Macintosh SE/30" in two places where it means the SE (the external floppy chart and the battery warning); the text is otherwise the SE's.[1]
Analogue board faults
[edit | edit source]Pina's entries for the SE and SE/30 analogue board, which the two machines share.[2]
| Symptom | Cause and fix | Page |
|---|---|---|
| Herringbone pattern across the display, early SE | Replace flyback T2 (157-0042A) with 157-0042C | 145 |
| Loud; display jitters and shakes, early SE | Replace crossflow fan B1 with a brushless 12 V DC fan | 146 |
| No startup sound, dark display, hissing or sizzling | Barrel rectifier CR2 (GI854, 600 V 3 A) shorted; Pina fits an MR824 (400 V 5 A) | 147 |
| No startup sound, dark display, no noise | CR3 shorted; horizontal output transistor Q2 (BU406D) burnt; if not, flyback T2 | 148 |
| Completely dead, no fan | On/off switch on the Sony CR44 supply | 149 |
| Startup sound, fan and disk run, dark screen, brightness has no effect | R22 (470 kΩ, ½ W) open | 150 |
| Right side wiggles, loud sizzling, just after an analogue board swap | Green ground wire from the supply not connected to the chassis | 151 |
| Right side moves in and out during disk access or when a window opens | CR2, then Q2 | 156–157 |
| Items on the left wider than on the right | C15 (3.9 µF non-polarised, 25/35 V); Pina fits a 100 V part | 159 |
| A few minutes after startup, vertical line on the right, then darkening and smoke | C15; check yoke plug P1 for burning | 160 |
| Bright vertical line instead of a picture, then smoke | C15; check P1 | 161 |
| Dim vertical line, then smoke | R19 (220 Ω) burnt; resolder linearity coil L3 with fresh solder | 162 |
| Picture collapses to a vertical line after a while; tapping the left of the cabinet brings it back | Cracked joints at P1 pin 4 and width coil L2 | 163 |
| Picture collapses to a horizontal line after a while; tapping brings it back | Cracked joint at P1 pin 1 | 164 |
| Very bright horizontal line instead of a picture | Vertical deflection IC U2 (TDA1170) | 165 |
| Top or bottom half squashed or stretched, bright line in the middle | U2 (TDA1170) | 170–173 |
| Too bright, scan lines visible with brightness down | R20 (100 kΩ) or R21 (1 MΩ) open; after a board swap, adjust R24 (Cut-off) | 166–167 |
| Very bright raster, no picture | U1 (SN74LS38N) on the analogue board; then Q1 (2N3904) on the CRT socket board | 168–169 |
| Out of focus | R26 (1 MΩ) open; after service, adjust R27 (Focus) | 215–216 |
| Picture too small or too large after a board swap or upgrade | Adjust R4 (Height) and coil L2 (Width) for 4.75 × 7.11 in | 152–155, 217 |
| Heavily upgraded SE goes "flup flup flup" and will not start | Power MOSFETs Q2 and Q3 (IRF830) in the Astec supply | 218 |
A single vertical line is a collapse of the horizontal sweep (C15, R19, L3, Q2, P1). A single horizontal line is a collapse of the vertical sweep (U2, P1 pin 1). Switch off as soon as either appears: Pina's entries end in smoke if the machine is left running.[2] Apple's size targets are 7 in wide by 4.7 in high.[1]
Logic board faults
[edit | edit source]| Symptom | Cause and fix | Page |
|---|---|---|
| Checkerboard pattern, no startup sound, right after an FDHD drive and ROM upgrade | ROMs or disk controller at D6, D7, D8 reversed or misplaced | 174 |
| Burning smell; internal and external SCSI devices do not mount, after a serial device or printer was plugged into the SCSI port | Rectifier CR1 (1N4001) at B4 burnt | 176 |
| Internal disk spins but SCSI devices do not mount; floppies work | SCSI controller NCR 5380 (40-pin DIP) | 177 |
| Keyboard and mouse dead after an ADB device was plugged in with the power on | Shorted filter 155-0007-E at A11 | 178 |
| Does not keep the time and date | Clock battery (early boards 3 V soldered, later 3.6 V in a holder) | 179 |
| Vertical bars; the smiling Mac never goes away, after a 1 MB to 2.5 MB upgrade | 1 MB SIMMs in the wrong row: sockets 1 and 2 on 820-0176 boards, 3 and 4 on 820-0250 boards | 206 |
| Tweeting noise at startup after a memory upgrade | A bad SIMM; check by substitution | 207 |
| No startup sound, otherwise normal, after an upgrade | Speaker cable off J11 | 213 |
| Upper floppy drive dead after an upgrade | Drive end of the data cable loose | 214 |
| "This disk is unreadable" dialog pointing at the startup disk or at a nonexistent external floppy drive | Filter networks 115-0002 (20-pin DIP) at B9 and B11 | 219–220 |
Sad Mac codes
[edit | edit source]Apple's chart sends Sad Mac codes to its faulty-SIMM table and the three-pin memory jumper.[1] Pina maps SE codes to individual SIMM sockets, and the socket depends on the bare board: 820-0176 (original) or 820-0250 (DIP SIMM). In the table, "n" is any digit.[2]
| Top line | Bottom line | 820-0176 board | 820-0250 board |
|---|---|---|---|
| 00000002, 00000003 or 0000000E | 000000nn or 00nn00nn | SIMM 1 | SIMM 3 |
| 00000002, 00000003 or 0000000E | 0000nn00 or nn00nn00 | SIMM 2 | SIMM 4 |
| 00000004 or 00000005 | 000000nn or 00nn00nn | SIMM 3 | SIMM 1 |
| 00000004 or 00000005 | 0000nn00 or nn00nn00 | SIMM 4 | SIMM 2 |
| Part of a Sad Mac, 0_0_0_0 | 0_F_0_F | Relatch SIMM 1 | Relatch SIMM 3 |
| Part of a Sad Mac, 0_0_0_5 | F_0_F_0 | Relatch SIMM 4 | Relatch SIMM 2 |
Pina also records 0000000F over 00000003, with the internal 20 MB drive "peeping" twice, as a MiniScribe 8425S with a damaged driver map, partition or directory (p. 202). For decoding codes in general see Sad Mac Error Codes and the Sad Mac Decoder.
Hard disk
[edit | edit source]Pina's entries for the internal 20 MB drive: a drive that spins but reports "bus not terminated" after being moved from an external HD20SC case has no terminators fitted at RP1–RP3 on its controller (p. 208), or a blown 1 A pigtail fuse at F1 on the controller (p. 209); after other work, check the SCSI data cable (p. 210).[2] For current drives and SCSI emulators see Macintosh HDD Maintenance and Hard Drive Maintenance and Repair.
Related pages
[edit | edit source]- Macintosh SE
- Macintosh SE General Maintenance
- Macintosh SE Capacitor Replacement Guide
- Macintosh SE Memory Upgrade Guide
- Macintosh Floppy Drive Maintenance
- Sad Mac Error Codes
References
[edit | edit source]- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 Apple Computer, Macintosh SE Service Source (126 pp.), hosted here as File:Macintosh SE.pdf (see Macintosh SE Service Source). Troubleshooting, Symptom Charts, PDF pp. 15–27; Take Apart, PDF pp. 29–69; Upgrades, PDF pp. 71–95; Additional Procedures, PDF pp. 97–111; Adjustments, PDF pp. 113–124.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 Larry Pina, The Dead Mac Scrolls, Peachpit Press, 1992, chapter 2 "Mac SE and SE/30", pp. 145–220; page numbers in the tables below are the book's, which match the PDF. Hosted here: File:The Dead Mac Scrolls 1992.pdf (see The Dead Mac Scrolls).
- ↑ 3.0 3.1 Apple Computer, Guide to the Macintosh Family Hardware, 2nd edition, Addison-Wesley, 1990, Chapter 6: Table 6-3, p. 248 (analogue board to logic board connector) and Table 6-15, p. 259 (output limits, Macintosh SE and SE/30). Hosted here: File:Apple Guide to the Macintosh Family Hardware 2nd Edition 1990.pdf.