Macintosh Centris 660AV Capacitor Replacement Guide
Replacing electrolytic capacitors (recapping) in your Macintosh Centris 660AV (also sold as the Quadra 660AV) is essential for long-term reliability. These machines are now over 30 years old, and surface-mount electrolytic capacitors are a common failure point.
Capacitor Inspection
[edit | edit source]Before beginning a recap, inspect the logic board for signs of capacitor failure:
- Bulging Tops – Capacitor tops should be flat. Any bulging indicates failure.
- Leaking Electrolyte – Brown or tan residue around capacitor bases or on the PCB.
- Corrosion or PCB Staining – Electrolyte is corrosive and can damage traces.
- Component Discoloration – Nearby resistors or chips may show heat damage.
Even capacitors that appear fine externally may be failing internally. Proactive replacement is recommended for any 660AV that has not been recapped.
Macintosh Centris/Quadra 660AV Capacitor List
[edit | edit source]Logic Board Capacitors
[edit | edit source]The 660AV logic board uses primarily surface-mount electrolytic capacitors. The following list is typical for these boards:
| Reference | Capacitance | Voltage | Type | Notes |
|---|---|---|---|---|
| C1 | 47µF | 16V | Electrolytic | Audio section |
| C2 | 47µF | 16V | Electrolytic | Audio section |
| C3 | 10µF | 16V | Electrolytic | |
| C4 | 10µF | 16V | Electrolytic | |
| C5 | 10µF | 16V | Electrolytic | |
| C6 | 10µF | 16V | Electrolytic | |
| C7 | 10µF | 16V | Electrolytic | Near SCSI |
| C8 | 10µF | 16V | Electrolytic | |
| C9 | 10µF | 16V | Electrolytic | Near ADB |
| C10 | 10µF | 16V | Electrolytic | |
| C11 | 1µF | 50V | Electrolytic | |
| C12 | 1µF | 50V | Electrolytic |
Note: Capacitor designations and exact values may vary between board revisions. Always verify against the actual markings on your board before ordering replacements.
Capacitor Location Diagram
[edit | edit source]The following diagram shows capacitor locations on the Quadra 660AV logic board:
Logic Board Reference Photo
[edit | edit source]
Power Supply Capacitors
[edit | edit source]The internal power supply also contains electrolytic capacitors that may need replacement. Warning: Power supplies contain hazardous voltages. Discharge all capacitors before servicing.
Replacement Parts
[edit | edit source]Recommended replacement types:
- SMD Electrolytics: Panasonic FR, Nichicon UCD, or Rubycon ZLH series
- Through-hole (if converting): Panasonic FM, Nichicon PW, or Rubycon YXJ series
- Polymer alternatives: Panasonic OS-CON or Nichicon FPCAP (longer lifespan, but check footprint compatibility)
Order replacements with voltage ratings equal to or higher than the originals. Match or exceed the temperature rating (usually 105°C).
Capacitor Replacement Procedure
[edit | edit source]- Prepare the workspace – Use an ESD-safe mat and wrist strap. Have good lighting and magnification available.
- Remove the logic board – Disconnect all cables, remove any expansion cards, and slide the board out.
- Document capacitor locations – Photograph the board before removing any components.
- Desolder old capacitors – Use a temperature-controlled iron (300–350°C) and quality solder wick or a desoldering station. Hot air rework is effective for SMD components.
- Clean the pads – Remove all old solder and flux residue with isopropyl alcohol.
- Inspect for damage – Check traces around each pad for corrosion. Repair any damaged traces before proceeding.
- Install new capacitors – Observe correct polarity (negative stripe to negative pad). Use quality lead-free or leaded solder.
- Clean the board – Remove all flux residue with isopropyl alcohol and a brush.
- Inspect solder joints – Look for cold joints, bridges, or insufficient solder.
- Test before reassembly – Connect minimal components (power, video, keyboard) and verify the machine boots.
Recommended Tools
[edit | edit source]- Temperature-controlled soldering iron (Hakko FX-888D or equivalent)
- Fine soldering tips (chisel or conical, 1–2mm)
- Desoldering pump or quality solder wick
- Hot air rework station (optional but recommended for SMD)
- Fine leaded or lead-free solder (0.5–0.8mm)
- Flux (no-clean or water-soluble)
- Isopropyl alcohol (90% or higher) and ESD-safe brushes
- Multimeter with continuity testing
- Magnification (loupe, magnifying lamp, or microscope)
- ESD mat and wrist strap
- Safety glasses
Polarity Identification
[edit | edit source]On the Centris/Quadra 660AV logic board:
- PCB markings: The positive pad is usually marked with a + symbol or a filled pad
- Capacitor markings: The negative side has a stripe, often with minus signs
- Reference photos: Take pictures before removal to verify orientation
Voltage Check After Recap
[edit | edit source]After recapping, verify power rail voltages before extended use:
| Rail | Nominal | Acceptable Range |
|---|---|---|
| +5V | 5.00V | 4.85V – 5.15V |
| +12V | 12.0V | 11.9V – 12.7V |
Additional Tips
[edit | edit source]- Work in small sections – Replace a few capacitors at a time to avoid errors
- Don't overheat pads – Limit iron contact to 3–4 seconds to prevent trace lifting
- Test incrementally – Boot the machine after each section to isolate any problems
- Keep original caps – Store them in case you need to verify values later
- Consider tantalum or polymer – For audio circuits, low-ESR polymer caps may improve sound quality
- Document your work – Keep notes and photos for future reference