Macintosh SE/30 Reloaded Logic Board

Assembled SE/30 Reloaded logic board

The Macintosh SE/30 Reloaded logic board is a modern recreation of the Macintosh SE/30 main logic board, published by Bolle. It is not a 1:1 copy: the original schematics were used to redesign and re-route a lookalike board.

The project files are released under CC-BY-NC-SA and are explicitly not intended for commercial use.

This page covers the recreation board. For the original machine see Macintosh SE/30; for repairing an original board, Macintosh SE/30 General Maintenance and the Macintosh SE/30 Capacitor Replacement Guide.

Why the board exists

An original SE/30 logic board fails in one characteristic way: its surface-mount electrolytic capacitors leak, the electrolyte corrodes traces and vias, and by the time the symptoms are obvious the damage is under the components. Boards that have lost traces in the video or sound sections are repairable but tedious, and some are beyond it. A new board lets the Apple-specific silicon from a damaged board be reused.

What the project reproduces, and what it does not

Reproduced. The board itself, and the programmable logic. The original PALs were reverse-engineered and their equations rewritten to match the behaviour of the originals; the JEDEC files supplied are not dumps of the original devices. They target 16V8-type parts — GAL16V8, PALCE16V8 or ATF16V8.

Reverse-engineered PALs and their original Apple part numbers

Board location	Original Apple part
UI6	341-0665-A
UH7	341S0689-C
UG6	341-0747-A
UG7	341-0746-A
UE6	341-0754-A
UE7	341-0755-A

Device caution from the project: certain low-power ATF16V8B parts do not work, and ATF16V8C parts use pin keepers rather than internal pull-ups and may also be problematic.

Not reproduced. Apple's custom devices — the CPU support ASICs, the sound and floppy controllers, the ROM — are not part of the project. They have to come from a donor logic board or from the parts market, which is why a corroded original is worth keeping rather than scrapping.

Files and manufacture

The gerbers are generated with the JLCPCB EAGLE CAM job files and the pick-and-place data is intended for JLCPCB; other manufacturers may require different output. A bill of materials is published with the project.

Consistency with the original

Two things are worth checking against the original machine's documentation rather than assumed:

• The SE/30's screen does not come out of main memory. The logic board carries a separate 64 KB video display RAM and an 8192-byte video declaration ROM mapped at $FE00 0000, which Apple calls pseudo-slot video. Any recreation has to provide both.
• The memory rules are the original machine's rules: eight 30-pin SIMM sockets in two banks of four, 120 ns or faster, eight chips per module, banks filled completely, larger modules in bank A. See Macintosh SE/30 Memory Upgrade Guide.

For tracing signals during a build, the MIT-licensed KiCad recreation of Apple engineering drawing 050-0253-01 hosted here is the most usable reference, and its pin matrices give the device at each location — UK8 CPU, UI5 FPU, UI8 GLUE, UK12/UK11 VIA1/VIA2, UJ11 SWIM, UI12 SCSI, UG12 SCC, UK6 video ROM, UC6/UC7 VRAM, J13 PDS.

Assembly

Before you start

Step	Detail
Clean	Isopropyl alcohol (>90 %) and a lint-free wipe, both sides.
Inspect	Under magnification, look for shorts, lifted pads and fabrication defects before any part is fitted.
Dry fit	Offer up sockets and the large connectors to check alignment.
ESD	Grounded wriststrap and an ESD-safe surface throughout.

Soldering

Component	Technique
0402/0603 passives	Tin one pad, place the part, solder the second pad, then reflow the first.
SOIC and QFP	Drag soldering or pin-by-pin, with plenty of flux.
PLCC	Tack opposite corners first, check seating, then solder the remaining leads.
Through-hole	Tack one pin, confirm the part is square and flush, then solder the rest and trim.

Use sockets for the CPU, FPU and ROM unless you are certain you will never need to swap them.

Through-hole connector installation

Suggested order

1. Power-related parts and the oscillator
2. Surface-mount passives
3. Surface-mount ICs and transistors
4. PLCC and DIP sockets, SIMM sockets
5. Connectors, headers, switches and jacks

First power-up

• Bring it up on a current-limited bench supply, not in the machine.
• Check the resistance between +5 V and ground before applying power; a dead short means a bridge or a reversed part.
• Verify each rail, then check for parts running hot.
• Only once the board is stable on the bench should it go into a chassis — where the CRT makes probing hazardous. Read CRT Discharge Procedure first.

Subsystem	Test
ROM and CPU	Boot chime and something on screen
RAM	Boots, and the reported total matches what is fitted
Video	Stable raster, correct geometry
Sound	Startup chime, then software playback
ADB	Keyboard and mouse respond
SCSI and floppy	Boot from known-good media; check termination

Troubleshooting a build

Simasimac

Symptom	Where to look
No boot, black screen	Oscillator, reset line, CPU orientation and socket seating
Simasimac (striped raster)	ROM access — socket seating, ROM SIMM contacts, and the RAM-signalling PALs
Death chimes	RAM: seating, bank population, SIMM speed, and the RAM-signalling PALs
No video, machine otherwise alive	Video ROM and the video PALs at UE6/UE7/UG6/UG7
No ADB, no floppy, no SCSI	Solder joints on the relevant connector and its support parts; then the donor ASIC

Faults specific to a hand-built board are overwhelmingly solder faults and wrong or missing programmable parts, not design faults. Compare a suspect signal against the schematic redraw before replacing anything.

Community resources

• Project repository — schematics, gerbers, JEDEC files and BOM
• 68kMLA forum — build threads and troubleshooting
• TinkerDifferent

Gallery

• 
  Assembled board
• 
  SMD soldering
• 
  Simasimac
• 
  Through-hole soldering

Related pages

• Macintosh SE/30
• Macintosh SE/30 General Maintenance
• Macintosh SE/30 Capacitor Replacement Guide
• Macintosh SE/30 Memory Upgrade Guide
• Recommended Tools