Macintosh LC II Capacitor Replacement Guide
Replacing the electrolytic capacitors (recapping) in the Macintosh LC II is essential for long-term reliability. The original capacitors used in these machines are now over 30 years old and commonly leak, causing corrosion and circuit damage.
Symptoms of Capacitor Failure
[edit | edit source]- No audio — Most common early symptom
- Distorted or crackling audio
- Boot failures or instability
- Visible electrolyte leakage — Brown or black residue around capacitors
- Corrosion on PCB traces
Capacitor List
[edit | edit source]Logic Board Capacitors
[edit | edit source]The Macintosh LC II logic board contains 17 surface-mount electrolytic capacitors, identical in specification to the original LC.
| Designator | Capacitance | Voltage | Type |
|---|---|---|---|
| C1 | 1 µF | 50V | SMD Electrolytic |
| C2 | 1 µF | 50V | SMD Electrolytic |
| C3 | 10 µF | 16V | SMD Electrolytic |
| C4 | 10 µF | 16V | SMD Electrolytic |
| C5 | 10 µF | 16V | SMD Electrolytic |
| C6 | 10 µF | 16V | SMD Electrolytic |
| C7 | 47 µF | 16V | SMD Electrolytic |
| C8 | 47 µF | 16V | SMD Electrolytic |
| C9 | 47 µF | 16V | SMD Electrolytic |
| C10 | 47 µF | 16V | SMD Electrolytic |
| C11 | 47 µF | 16V | SMD Electrolytic |
| C12 | 47 µF | 16V | SMD Electrolytic |
| C13 | 47 µF | 16V | SMD Electrolytic |
| C14 | 47 µF | 16V | SMD Electrolytic |
| C15 | 100 µF | 6.3V | SMD Electrolytic |
| C16 | 100 µF | 6.3V | SMD Electrolytic |
| C17 | 100 µF | 6.3V | SMD Electrolytic |
Power Supply Capacitors
[edit | edit source]The LC II uses the same power supply as the original LC. Refer to the Macintosh LC Power Supply Recap Guide for PSU-specific information.
Capacitor Replacement Procedure
[edit | edit source]Tools Required
[edit | edit source]- Temperature-controlled soldering iron (recommended: 300-350°C)
- Fine tip for SMD work
- Desoldering braid or solder wick
- Flux (no-clean recommended)
- Isopropyl alcohol (99%)
- Soft brush (ESD-safe)
- Multimeter
- Replacement SMD electrolytic capacitors
Procedure
[edit | edit source]- Remove the logic board — Disconnect all cables, remove screws, and carefully lift the board.
- Document capacitor positions — Note polarity markings before removal.
- Clean the area — Remove any leaked electrolyte with isopropyl alcohol.
- Remove old capacitors — Heat one pad while gently lifting the capacitor. Alternate between pads. Use flux to help solder flow.
- Clean the pads — Remove old solder with desoldering braid. Clean with IPA.
- Inspect for damage — Check traces and vias for corrosion. Repair any damaged traces.
- Install new capacitors — Observe polarity. The stripe on the capacitor indicates negative. Tin one pad, position capacitor, solder second pad, reflow first pad.
- Clean residue — Remove flux with isopropyl alcohol.
- Test continuity — Verify no shorts between +5V, +12V, and ground.
- Reassemble and test — Listen for the startup chime, verify video, and check audio output.
Important Notes
[edit | edit source]- Polarity matters — SMD electrolytics will fail if installed backwards.
- Use equivalent or better specs — Match capacitance; voltage rating can be equal or higher.
- Low-ESR capacitors — Modern low-ESR replacements are acceptable.
- No FPU socket — Note that the LC II does not have an FPU socket on the logic board, despite the 68030's FPU support.