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Macintosh SE/30 Reloaded Logic Board

From RetroTechCollection
Macintosh SE/30 Reloaded Logic Board
Caption Fully assembled SE/30 Reloaded Logic Board
Type Logic Board
Designer Community-designed (Based on original Apple SE/30)
Manufacturer Independent / DIY
First released 2023
Latest revision N/A
Operating voltage
Layers / PCB 4-layer PCB
Compatibility Macintosh SE/30
Features Modern design, SMD components, Apple ASICs, GAL-based PAL replacements, 32-bit clean ROM support
Model No. SE30RL

The Macintosh SE/30 Reloaded Logic Board is a modern re-imagining of the original Macintosh SE/30 motherboard. Unlike a one-to-one clone, this project redesigns the logic board using a 4-layer PCB, modern surface-mount components, and enhanced reliability. It is functionally compatible with the original Mac SE/30 and accepts most of its original chips and connectors.

Fully assembled SE/30 Reloaded Logic Board

Preparation and Inspection

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Step Description
Cleaning Use >90% isopropyl alcohol and a lint-free wipe to clean both sides of the board.
Inspection Under magnification, inspect the PCB for any shorts, broken pads, or fabrication issues.
Dry Fit Checks Fit sockets and large connectors to verify alignment.
ESD Precautions Always wear a grounded wrist strap and work in an ESD-safe area.

Required Components and Tools

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Required Components and Tools

Components Tools
  • Apple custom ASICs: GLU, ASC, SWIM, ADB, RTC
  • 6× GAL16V8 chips (programmed)
  • EPROM (27C64 Video ROM)
  • SMD & through-hole capacitors, resistors, diodes
  • Connectors, SIMM sockets, ROM SIMM
  • Temperature-controlled soldering iron
  • Hot air rework station
  • Fine-gauge solder (0.5mm)
  • No-clean flux pen and syringe flux
  • ESD tweezers and microscope
  • Multimeter, oscilloscope, logic analyzer (optional)
  • GAL and EPROM programmers

Assembly Techniques

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Surface-Mount Soldering

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Component Technique
0402/0603 passives Pre-tin one pad, place the component, solder the second pad.
SOIC, QFP ICs Use drag soldering or pin-by-pin with ample flux.
PLCC ICs Align carefully; tack corners; drag or point solder the leads.

Through-Hole Soldering

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Proper through-hole connector installation (placeholder)
  • Use sockets for CPU, FPU, ROM unless soldering directly.
  • Align and tack first, then solder each pin.
  • Use flush cutters to trim excess leads.
  • Confirm each pin has solid contact and solder fill.
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  1. Power-related components (fuses, oscillator)
  2. All SMD passives
  3. SMD ICs and transistors
  4. PLCC/DIP sockets and SIMM connectors
  5. External ports, headers, switches, and jacks

Initial Testing and Diagnostics

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Power Check

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  • Use a bench power supply with current limiting.
  • Check resistance between +5V and GND before powering.
  • After applying power: verify +5V, +12V, and -12V rails.
  • Feel for overheating components.

Subsystem Tests

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Subsystem Verification

Subsystem Test
ROM/CPU Boot chime, screen output
RAM System boots, memory reported in OS
Video CRT displays proper raster and icons
Sound Audible startup chime and software playback
ADB Mouse and keyboard functionality
SCSI/Floppy Boot from known-good media, verify termination and data lines

Troubleshooting

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Simasimac error screen
Symptom Potential Cause
No boot, black screen Check clock oscillator, reset pin, CPU alignment
Simasimac ROM access failure, bad socket, missing GALs
Death chimes RAM error, GAL timing, bad addressing
Blank video Video ROM missing, UE8 or PAL issue
No ADB Fuse F1, ADB chip (UL11), PRAM battery
No floppy Check SWIM chip, F3 fuse, D3 diode
No SCSI Termination issue, 53C80 controller

Key Improvements Over Original

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  • 4-layer PCB reduces noise and improves signal reliability.
  • No electrolytic capacitors – replaced with SMD ceramics/tantalum.
  • Standardized SIMM and ROM socket layout.
  • Optional 32-bit clean ROM support (no need for MODE32).

Community Resources

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