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.
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
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
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
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. Recommended Assembly Sequence
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Power-related components (fuses, oscillator)
All SMD passives
SMD ICs and transistors
PLCC/DIP sockets and SIMM connectors
External ports, headers, switches, and jacks Initial Testing and Diagnostics
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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 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
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).
SMD soldering
Simasimac
Through Hole Soldering
SMD soldering
Simasimac
Through Hole Soldering