Macintosh Centris 660AV General Maintenance

Proper maintenance is essential to extending the lifespan and ensuring reliable operation of your Macintosh Centris 660AV (also sold as the Quadra 660AV). The following sections provide guidance on cleaning, battery management, and preventative care.

Regular Cleaning

Internal Cleaning

Power off and unplug the computer; allow it to sit for at least 15 minutes
Remove the top cover by pressing the release tabs on either side
Use compressed air to remove dust from the logic board, power supply, and fan
Pay attention to the ventilation slots and fan area
Clean the floppy drive heads with a cleaning disk if read errors occur
Inspect all socketed chips for corrosion or oxidation

External Cleaning

Wipe the case with a slightly damp, lint-free cloth
Clean the ventilation grilles with a soft brush or compressed air
Use isopropyl alcohol for stubborn marks on the plastic case
Do not spray liquids directly onto the computer

Keyboard and Mouse Cleaning

Remove keycaps and clean underneath with compressed air
Wipe keycaps with isopropyl alcohol
Clean the mouse ball and rollers (if applicable) with isopropyl alcohol
For ADB mice, inspect the cable for damage near the connector

PRAM Battery Handling

The Centris/Quadra 660AV uses a 3.6V half-AA lithium battery for PRAM.

Best Practices

Replace the battery every 3–5 years, even if the computer still boots correctly
Always use a quality replacement (Maxell, Tadiran, or equivalent)
Never attempt to recharge the lithium battery
A dead battery can cause loss of built-in video (see Apple KB TA35928)

Cleaning Battery Leakage

If the PRAM battery has leaked:

Remove the battery immediately and dispose of it properly
Clean affected areas with white vinegar to neutralize the electrolyte
Follow up with isopropyl alcohol to remove residue
Inspect nearby traces and components for corrosion damage
Use a fiberglass pen or DeoxIT to clean corroded contacts

Connector and Socket Corrosion

Key Areas to Check

SIMM sockets – Clean contacts with DeoxIT or isopropyl alcohol
PDS/NuBus slot – Inspect for oxidation on contacts
Power connector – Check for discoloration or heat damage
ADB ports – Look for bent pins or corrosion
Serial ports – Verify all pins are straight and clean
Video connector – Inspect for damaged or corroded pins

Apply DeoxIT D5 to all socketed connections and card edge connectors during maintenance.

Common Failure Points

Power Supply

The internal power supply can accumulate dust on the filter mesh near the fan. A "bad" power supply may be restored by clearing this dust buildup.

Capacitor Health

The logic board contains electrolytic capacitors that can leak or fail after 25+ years. See Macintosh Centris 660AV Capacitor Replacement Guide for detailed information.

Symptoms of capacitor failure:

Machine fails to boot or boots intermittently
Audio distortion or no sound
Visible electrolyte residue on the logic board
Corroded traces near capacitors

PRAM Battery Damage

Dead or leaking PRAM batteries are a common failure point. Symptoms include:

Loss of date/time settings
Loss of display settings
Complete loss of built-in video
Failure to boot

Floppy Drive

Early Centris 660AV units have auto-inject floppy drives that can fail. Later Centris and all Quadra 660AV units use manual-inject drives. Common issues:

Dirty or worn heads
Belt deterioration (auto-inject models)
Mechanical eject failure

Logic Board Socket Oxidation

The 660AV has socketed components that can develop oxidation over time:

CPU socket (if socketed)
ROM SIMM socket
RAM SIMM sockets

Regular cleaning with DeoxIT helps prevent contact issues.

Voltage Adjustment and Power Checks

The 660AV power supply provides the following rails:

Rail	Nominal	Acceptable Range
+5V	5.00V	4.85V – 5.15V
+12V	12.0V	11.9V – 12.7V

Measure voltages at the power connector with the machine running under normal load. Voltages outside these ranges may cause instability.

Related Maintenance Pages