Macintosh Color Classic II General Maintenance
Maintenance guidance for the Macintosh Color Classic II, also sold as the Macintosh Performa 275. It was not sold in the United States.[1]
The logic board comes out without opening the case. Apple's take-apart procedure for it begins "No preliminary steps are required": open the I/O door at the back and pull the board straight out.[2] The battery change and the logic board recap therefore involve no CRT and no high voltage.
Safety
[edit | edit source] | The Color Classic II has a 10-inch (9-inch viewable) Trinitron CRT.[3] The anode holds charge after the machine is unplugged, and the analogue board is a mains-connected switch-mode supply whose primary reservoir, CP30, is a 330 µF 400 V capacitor.[4] Discharge the anode before working inside the case and measure across CP30 before touching the primary side. See CRT Discharge Procedure. |
Apple's adjustment topics add: never use metal alignment tools, which are a shock hazard; the whole yoke assembly carries very high voltage; and with the rear housing off, the metal chassis can buckle and short to the bottom of the logic board, so check clearance before switching on.[5]
Removing the logic board
[edit | edit source]- If fitted, remove the two security screws from the I/O door.
- Push down the two latches until the I/O door snaps open, and remove the door.
- Grasp the logic board with both hands and pull it straight out of the chassis onto a grounded mat.[2]
On refitting, check that no bent metal tabs on the chassis can touch the underside of the board and short it.[2]
Opening the case
[edit | edit source]Only needed for the analogue board, the CRT, the drives or the fan.
- Remove the four case screws with a long-handled Torx driver, and the two I/O door security screws if fitted.
- Separate the rear housing from the chassis with a case spreader and lift it away.
- Discharge the CRT and remove the anode cap before touching the analogue board.
All from Apple's Take Apart.[2] The chassis edges are sharp once the housing is off. To replace a damaged rear housing, the fan comes off it first.[2]
Cleaning
[edit | edit source]- Blow dust out of the logic board, the analogue board and the CRT neck area with compressed air, and clean the fan blades and vents.
- Use isopropyl alcohol and a soft brush for anything the air will not shift. Do not spray liquid at the CRT neck or the flyback.
- Clean the outside of the screen with a damp microfibre cloth.
- The machine uses standard ADB peripherals. Apple specifies a 500 mA maximum draw across the ADB ports (mouse 10 mA, keyboard 25 mA) and recommends no more than three devices.[3]
PRAM battery
[edit | edit source]Apple's procedure is to remove the logic board, set the meter to the 10 V DC range, and replace the cell if it reads below 3.0 V.[6] Apple's warning: "If handled or discarded improperly, the lithium battery in the computer could explode."[6] Low End Mac gives the cell as a 3.6 V half-AA.[1]
- Check for corrosion around the cell and on nearby traces before anything else.
- Lithium-cell residue is acidic: neutralise it with bicarbonate of soda, then clean with water and isopropyl alcohol. Vinegar is for the alkaline packs in the Macintosh Plus and Macintosh 512K.
- Check continuity around the battery area and repair broken traces with fine wire.
- Take the cell out of a machine going into storage.
See Battery Explosion, Capacitor or Corrosion Damage and Battery Refurbishment.
Connectors
[edit | edit source]- The flat-cable assembly (Apple part 922-1804) carries the floppy and hard disk connections. Apple's symptom charts send several floppy and hard-disk faults to it.[7][8]
- The yoke cable (BD1), degauss cable (BP2) and microphone cable all plug into the analogue board.[2]
- The logic board power cable connects at J12. Apple's first step for clicking, chirping or thumping is to check it.[7]
- Reseat the RAM and VRAM SIMMs if you see memory errors. Apple's manual describes the RAM slot as two 30-pin connectors, but Low End Mac and EveryMac give one 72-pin socket; see the memory section before buying memory.[9]
Capacitors
[edit | edit source]Both boards use electrolytic capacitors that leak. On the logic board they sit around the sound chip in the top left corner, and Recap-a-Mac reports damaged traces there as common.[10] See Macintosh Color Classic II Capacitor Replacement Guide and Capacitor Failure Symptoms.
Analogue board and power supply
[edit | edit source]
The analogue board is the power supply: Apple lists a single "Analog Board/Power Supply", part 661-0732, the same module as the Macintosh Color Classic.[8]
Apple's symptom chart for what belongs to this board:[7]
| Symptom | Apple's cures, in order |
|---|---|
| Clicking, chirping or thumping | Check the logic board power cable at J12; analogue board; logic board |
| Smoke or odour | Analogue board |
| No video, no audio, no drive operation | Connect the power cord; switch on; replace the power cord; analogue board; logic board |
| Flashing or wavy screen, or a high-pitched noise | Analogue board |
| Screen jitters or flashes | Check nearby equipment is grounded, move electrical devices away, switch off fluorescent lights; check all ground cables are secure; analogue board |
| Picture breaks into diagonal lines, or rolls | Analogue board |
| Out of convergence | Convergence adjustment; analogue board; CRT |
Recap-a-Mac singles out the 3300 µF 16 V capacitor near the middle of the board, which can leak and disturb the display.[11] On the Color Classic version of this board, TinkerDifferent members report the zener diodes DL21 and DL22 scorching the board and the resistor RL62 burning; see the Color Classic capacitor guide.[12]
Apple publishes no rail voltages or tolerances for this machine and no voltage adjustment; its Adjustments chapter covers geometry, video, convergence, geometric distortion, yoke and light meter setup.[5] Compare each rail with its nominal value at the logic board connector.
Specifications for maintenance
[edit | edit source]| Item | Figure |
|---|---|
| Line voltage | 90–240 V AC, universal power supply |
| Frequency | 47–63 Hz, single phase |
| Maximum power | 100 W |
| Processor | Motorola 68030 at 33 MHz |
| Display | 10-inch diagonal (254 mm), 9-inch viewable (228 mm) Trinitron, 512 × 384 at 76 dpi |
| ADB maximum current | 500 mA total |
| Operating temperature | 10–40 °C (50–104 °F) |
| Relative humidity | 20–95 % non-condensing |
All from Apple's Specifications chapter.[3] Keep the rear vents clear and check that the fan (Apple part 922-1803) turns.[8]
Related pages
[edit | edit source]- Macintosh Color Classic II
- Macintosh Color Classic II Troubleshooting
- Macintosh Color Classic II Capacitor Replacement Guide
- Macintosh Color Classic II/ Performa 275 Service Source
- Battery Explosion, Capacitor or Corrosion Damage
- Capacitor Failure Symptoms
- CRT Discharge Procedure
- Sad Mac Error Codes
- Retrobrite
References
[edit | edit source]- ↑ 1.0 1.1 Low End Mac, "Mac Colour Classic II (Performa 275)": sold in Canada, then Asia and Europe, never in the US; PRAM battery 3.6 V half-AA; logic board shared with the Performa/LC 550. Secondary source.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 Apple Computer, Macintosh Color Classic II/Performa 275 Service Source (137-page copy, File:Color classic ii.perf 275.pdf), Take Apart pp. 1–41 (PDF pp. 36–76): Logic Board, Rear Housing, Analog Board, Speaker, Floppy Drive, Hard Drive, Chassis, Pushbutton Board, Flat-Cable Assembly, Microphone Assembly, CRT, Degauss Coil, Bezel, Fan.
- ↑ 3.0 3.1 3.2 Apple, Macintosh Color Classic II/Performa 275 Service Source, Specifications pp. 1–12 (PDF pp. 5–16).
- ↑ powercc.org, "ReCap": Color Classic analogue board capacitor list, including CP30 330 µF 400 V and CF8, CP39 3300 µF 16 V. Secondary source.
- ↑ 5.0 5.1 Apple, Macintosh Color Classic II/Performa 275 Service Source, Adjustments pp. 1–40 (PDF pp. 96–135).
- ↑ 6.0 6.1 Apple, Macintosh Color Classic II/Performa 275 Service Source, Additional Procedures, Battery Verification and Battery Replacement pp. 1–5 (PDF pp. 90–94).
- ↑ 7.0 7.1 7.2 Apple, Macintosh Color Classic II/Performa 275 Service Source, Troubleshooting, Symptom Charts pp. 2–17 (PDF pp. 19–34).
- ↑ 8.0 8.1 8.2 Apple, Macintosh Color Classic II/Performa 275 Service Source, Exploded View (PDF p. 137): Analog Board/Power Supply 661-0732; logic board 661-1830; flat cable assembly 922-1804; fan 922-1803; degauss coil 922-1816; CRT 661-0004 (661-0024 Australia, 661-0022 Europe).
- ↑ Apple, Macintosh Color Classic II/Performa 275 Service Source, Upgrades, Memory Upgrade pp. 6–8 (PDF pp. 83–85).
- ↑ Recap-a-Mac, "Macintosh Colo(u)r Classic II". Secondary source.
- ↑ Recap-a-Mac, "Macintosh Colo(u)r Classic Analog Board". Secondary source.
- ↑ TinkerDifferent, "Color Classic analog board trouble", 2023. Secondary source.