Macintosh SE/30 Capacitor Replacement Guide

Replacing electrolytic capacitors (recapping) in your Macintosh SE/30 is essential for restoring power stability, ensuring clean video output, and preventing long-term damage due to capacitor leakage. This guide outlines the recommended procedure and provides complete analog and logic board capacitor specifications.

Capacitor Inspection

Before recapping, visually inspect all capacitors for common signs of failure:

• Bulging Tops – Swollen or domed caps indicate internal gas buildup.
• Electrolyte Leakage – Brown/white crust or residue near leads shows capacitor failure.
• Corroded Pads or Traces – PCB staining or corrosion suggests leakage damage.

If any of these symptoms are present, immediate replacement is advised.

Macintosh SE/30 Capacitor List

Analog Board Capacitors

The SE/30 analog board is nearly identical to that of the Macintosh SE and Plus, and shares the same capacitor layout:

SE/30 Analog Board Capacitor Specifications

Label	Capacitance	Voltage	Quantity
C1	3.9µF	35V	1x
C2	4700µF	16V	1x
C3	220µF	16V	2x
C5	47µF	10V	1x
C6	22µF	50V	2x
C10	33µF	16V	2x
C11	10µF	160V	1x
C12	22µF	50V	2x
C18	33µF	16V	2x
C24	2200µF	16V	4x
C27	2200µF	16V	1x
C28	1000µF	16V	1x
C30	2200µF	16V	1x
C31	220µF	16V	1x
C32	2200µF	16V	1x
C33	4700pF	250V	2x
C34	100µF	200V	4x
C35	100µF	200V	1x
C36	4700pF	250V	1x
C37	0.47µF	250V	1x
C38	100µF	200V	1x
C39	100µF	200V	1x
C42	470µF	10V	2x
C45	470µF	10V	1x

Logic Board Capacitors

The SE/30 logic board is particularly prone to capacitor failure and corrosion, making recapping especially important.

SE/30 Logic Board Capacitor Specifications

Label	Capacitance	Voltage	Quantity
C1 – C10	47µF	16V	10x
C11	1µF	50V	1x

Macintosh SE/30 Logic Board Capacitor Locations

Capacitor Replacement Procedure

1. Discharge the CRT – Follow standard CRT discharge procedures before working inside.
2. Remove the Logic & Analog Boards – Label cables and safely extract both boards.
3. Desolder Old Capacitors – Use a quality soldering iron, braid, or pump to remove components cleanly.
4. Install New Capacitors – Insert with correct polarity (check for stripe on negative side).
5. Solder Carefully – Ensure clean, shiny joints without cold solder bridges.
6. Trim Leads & Inspect Work – Cut excess and examine under light or magnification.
7. Test for Shorts – Use a multimeter to confirm there are no shorts across power rails.

Recommended Tools

• Temperature-controlled soldering iron (fine tip)
• Desoldering braid or vacuum pump
• Quality leaded solder (0.5 mm recommended)
• Isopropyl alcohol and ESD brush
• Multimeter
• Safety goggles and insulated gloves

Voltage Adjustment After Recap

Measure voltages at the floppy drive or logic board power connector:

• +5V rail: 4.85V – 5.15V
• +12V rail: 11.9V – 12.7V

Use the analog board's trimmer potentiometer (R56) to fine-tune if necessary.

Tips for Best Results

• Always recap the logic board first – leaking caps often cause corrosion damage.
• Use quality capacitors (e.g., Nichicon, Panasonic, Rubycon).
• Turn on the system periodically to prolong capacitor lifespan.
• Replace in full sets for even aging and reliability.
• Clean the board thoroughly with isopropyl alcohol after removal.

Related Pages

• Macintosh SE/30 General Maintenance
• Macintosh SE/30 Troubleshooting
• CRT Discharge Procedure