Power Macintosh 6500 Troubleshooting

Power Macintosh 6500. Photo: Ben Boldt, Wikimedia Commons, public domain

The tables below are Apple's symptom charts for the Power Macintosh 6500, from the Performa/Power Macintosh 6400 and 6500 Series Service Source. Entries that apply only to the 6400 are left out. Apple lists the cures in order of likelihood: try the first, check whether the symptom persists, and refit the original module before trying the next (p. 75).

Before you start

Check the voltage switch on the back before applying power. Apple says it "must be set correctly to avoid damaging the computer": "115" for 100–130 V, "230" for 200–270 V (p. 17). Apple's chart for a CD-ROM drive with no power includes checking the switch and replacing the power supply if it was in the wrong position (p. 88).

A logic board reset is Apple's first cure for a machine that will not start: remove the logic board, unplug the battery for 5 to 10 minutes, refit it, press the reset switch and reseat the board (pp. 213–216). The battery is replaced below 3.0 V (p. 210); its chemistry is covered on Power Macintosh 6500 General Maintenance.

System

System

Symptom	Apple's cures, in order
Crashes or hangs intermittently	Check system software is 7.5.3 or later, known-good and PowerPC-compatible; clear PRAM (Command-Option-P-R before "Welcome to Macintosh"); disconnect external devices except the monitor and restart; replace the DIMMs; replace the logic board; replace the power supply.
Does not start up	Reset the logic board; replace the power supply; replace the logic board.
Does not start from the keyboard, but starts from the power switch	Check the keyboard connection; try a known-good keyboard.
Menu bar flashes or the system beeps constantly	Check the front-panel buttons are not jammed.
Software installation fails with "Unable to decompress file ... data mismatch error", or the system hangs, freezes or gives a Type 10 error	On serial numbers XB708xxxxx to XB718xxxxx with an OPC-made logic board and an incompatible L2 cache DIMM, replace the cache with 661-1477 (details on Power Macintosh 6500).

Source: pp. 76–77, 96.

Video

Video

Symptom	Apple's cures, in order
No video, fan running	Check the monitor connection; try a known-good monitor; replace the monitor-out card; remove the DIMMs and refit them one at a time to find a bad one; replace the logic board; replace the power supply.
Blurry image over the whole screen at 832 × 624 and above	Serial numbers XB708xxxxx to XB723xxxxx: replace the audio/monitor connection subassembly with 922-2996. Check for the three red capacitors first (pp. 221–223).
Pixels shimmer at the edges of the screen, dialog boxes or windows	Replace the logic board with a reworked one (661-1322 for 225 MHz, 661-1332 for 250 MHz). Check resistor R363 first: "100" means not reworked, "101" reworked (pp. 219–220).
Poor video (misaligned or skewed, dim, blurred)	Set the resolution to 1152 × 870 or lower in the Monitors and Sound control panel.
Output from the NTSC video-out card intermittently turns black and white	Zap PRAM; clean the contacts at the end of the card's ribbon cable where it fits the external video slot; replace the card.
NTSC video-out card shows flickering lines across the screen	Zap PRAM; replace the card.

Source: pp. 79–81. The chart gives the jitter range as XB708xxxxx to XB719xxxxx; the Additional Procedures page for the same fault gives XB708xxxxx to XB718xxxxx (p. 218).

Audio

Audio

Symptom	Apple's cures, in order
Distorted or garbled sound	Check the volume level, and the level in the Sound control panel.
No sound from the speaker	Check the speaker connection to the logic board; replace the speaker assembly; if headphones work, replace the speaker assembly.
Headphone jack does not work properly	Check the jack is seated; replace the front panel control board; replace the chassis/wiring harness (ordered as the metal chassis).

Source: pp. 78, 95. The internal speaker is mono, and plugging into either output jack mutes it (pp. 21, 70).

Drives

Floppy, hard, CD-ROM and Zip drives

Symptom	Apple's cures, in order
Floppy drive does not work, audio and video present	Try a known-good disk; replace the floppy drive; replace the logic board.
Disk ejects and the screen shows a disk icon with a blinking X	Try a known-good system disk; replace the floppy drive; replace the logic board.
Disk will not go in or will not eject	Use a straightened paper clip in the hole beside the drive; switch on holding the mouse button; replace the floppy drive.
Floppy drive runs continuously	Try a known-good disk; replace the floppy drive; replace the logic board.
Hard drive does not spin up	Check the drive connections and external termination; reseat the logic board; replace the IDE drive; replace the logic board; replace the chassis/wiring harness (ordered as the metal chassis).
Hard drive runs continuously	Check system software is 7.5.3 or later; replace the drive cable; replace the drive; replace the logic board.
Hard drive not found when started from CD-ROM	Use Drive Setup to try to mount it.
CD-ROM drive does not accept a disc	Try a known-good disc; replace the drive.
Vibration noise from the 12× CD-ROM drive	Normal for a 12× drive at high rotation speed.
Known-good discs will not mount	Check the CD-ROM software; reseat the CD-ROM adapters; check the SCSI ID (set to 3 at the factory); replace the drive; replace the chassis/wiring harness.
CD not recognised, or drive has no power	Reseat the logic board to re-establish its connection to the chassis; remove the hard drive and read the white pull tab: if it says anything other than Foxconn, replace the chassis with 922-2707; check the voltage switch, and replace the power supply if it was set wrongly.
Zip drive not on the desktop with a disk inserted	Try a known-good Zip disk; check the cables; reinstall system software; replace the Zip drive.
Type 4 errors with the Zip drive	Check the cables; replace the Zip drive.

Source: pp. 82–92. See also Floppy Drive Repair and Hard Drive Maintenance and Repair.

Peripherals

Peripherals

Symptom	Apple's cures, in order
Cursor does not move	Restart; check the mouse connection; if the mouse was on the keyboard, move it to the rear ADB port (if it works there, replace the keyboard; if not, the mouse); reseat, then replace, the logic board.
Cursor moves but clicking does nothing	Replace the mouse; reseat, then replace, the logic board.
Cannot double-click to open anything	Check the mouse speed setting; unplug the battery from the logic board for 20 seconds and restart; test the mouse on the rear ADB port; replace the logic board.
No response from the keyboard	Check system software is 7.5.3 or later; check the ADB connection; replace the keyboard; reseat, then replace, the logic board.
Known-good StyleWriter or LaserWriter does not print	Check the Chooser; check the driver and system software; for a StyleWriter, replace the printer cable, then the logic board.
SCSI device not recognised	Check termination and the cable; check the device's software; use the 6360/64xx/54xx Update disk to correct a possible SCSI timing problem.

Source: pp. 89–91.

Miscellaneous

Miscellaneous

Symptom	Apple's cures, in order
No audio and no drive activity	Connect the power cable; switch on; replace the power cable; replace the logic board.
Sad Macintosh icon	Start from a known-good disk; replace the DIMMs; replace the logic board.
Sad Macintosh icon with black vertical lines and a screeching sound	Replace the DIMMs; replace the logic board.

Source: pp. 94–95. Startup tones and codes are covered on Sad Mac Error Codes.

Beyond module level

Apple's manual has no schematics, component values or rail voltages. The only capacitors it mentions are the three on the audio/monitor connection subassembly used to identify the blurry-video fault. See Power Macintosh 6500 Capacitor Replacement Guide.

Related pages

• Power Macintosh 6500
• Power Macintosh 6500 Specifications
• Power Macintosh 6500 General Maintenance
• Power Macintosh 6500 Capacitor Replacement Guide
• Performa/Power Macintosh 6400 and 6500 Series Service Source