Power Macintosh 8500 Troubleshooting
Fault finding on the Power Macintosh 8500 starts from Apple's symptom charts in the Power Macintosh 8200 and 8500 Series/WS 8550 Service Source. Apple lists the cures in order of likelihood: try the first, check whether the symptom remains, and refit the original part before moving on (SS p. 53).[1] Opening the case, the resets and the battery are on Power Macintosh 8500 General Maintenance.
Power and startup
[edit | edit source]| Symptom | Cures, in order | SS page |
|---|---|---|
| Does not power up | Reseat the processor card and the ROM SIMM if fitted; reset the Cuda chip; reset the logic board; replace the power supply, the processor card, the logic board | 55 |
| Does not power on; screen black, fan not running, LED off | Check the power cables; plug the monitor into the wall and check it has power; reseat the ROM SIMM and the processor card (the board will not run without a card); reset the Cuda chip and the logic board; replace the power cord, the power supply, the processor card, the logic board | 58 |
| Clicking, chirping or thumping | Remove all PCI cards and refit them one at a time; remove the hard drive; replace the power supply, the processor card, the logic board, the floppy cable, the floppy drive | 59 |
| Shuts down intermittently | Clear the vents (thermal protection; allow 30 to 40 minutes); check the power cord; replace it; check the battery; reset the Cuda chip and the logic board; replace the power supply, the processor card, the logic board | 60 |
Owners have reported:
- An 8500 with a flat clock battery that stopped responding to the power key and the front button; another owner advises taking out the battery and pressing the Cuda reset button.[2] Apple's charts also list "Check battery" for intermittent shutdowns (SS p. 60).[1]
- A logic board that would not start on the bench outside the case until it was grounded to the power supply frame, as the shielding at the back of the case does in normal use.[3]
- A recapped 8500/150 that showed no sign of life although its supply ran a 9500 board; the first advice was to reseat the processor card.[4]
Power supply checks
[edit | edit source]The supply connects to the logic board with a 22-pin cable carrying +5 V and ±12 V and a 10-pin cable carrying 3.3 V for the processor card (SS p. 105).[1] Owners report that the 8500 and 9500 use the same supply connectors as the 7200, whose pinout from Apple's schematic is on Power Macintosh 7200 Troubleshooting, and that 8500 and 9500 supplies have been used to run 8100 and Quadra 840AV boards.[5][6][7] Apple gives no rail tolerances. Measure +5 V, +12 V, −12 V and +3.3 V at the connectors with the computer running, and check that trickle 5 V is present with the supply plugged in. The supply's primary capacitors hold mains-derived voltage; discharge them and confirm with a meter before touching the board.
Startup sounds and video
[edit | edit source]| Symptom | Cures, in order | SS page |
|---|---|---|
| One-part error chord | Disconnect the SCSI cable from the hard drive and restart; initialise or replace the drive if the startup is then normal. Disconnect the floppy cable and restart; replace the floppy drive if the startup is then normal. Reseat, then replace, the processor card; replace the logic board | 56 |
| Eight-part chord (death chimes) | Replace the DRAM DIMMs one at a time to find a faulty one; replace the logic board | 57 |
| Screen black; boot tone, drive working, fan running, LED lit | Turn up the brightness; clear PRAM; reset the Cuda chip and the logic board; replace the monitor cable; test the DIMMs one at a time; try a known-good monitor; replace the processor card, the logic board | 64 |
| Screen black; no boot tone, drive not working, fan running, LED lit | Reset the Cuda chip and the logic board; test the DIMMs one at a time; replace the processor card, the logic board, the power supply | 65 |
| Boot tone; screen lights but shows nothing | Reset the Cuda chip and the logic board; replace the monitor cable; try a known-good monitor; replace the processor card, the logic board | 66 |
| Distorted video with a card on the DAV connector | The card needs DAV Mode 2: boards with 820-0752 silkscreened, and 820-0564 boards with Apple's jumper wire near U18, support it; replace any other board | 67–68 |
Crashes and system software
[edit | edit source]For intermittent crashes or hangs, Apple's order is: check the system software is at least 7.5.2 (8500/120) or 7.5.3 (8500/132, 8500/150 and WS 8550); check the DIMMs are noncomposite; do a clean install; check the software is compatible and try starting with extensions off; clear PRAM (Command-Option-P-R at startup); test the DIMMs one at a time; replace the processor card, then the logic board (SS p. 61).[1] The 8500/150 with the 8× CD and the 8500/180 need 7.5.3 Revision 2 (p. 39).[1]
Errors when initialising floppy disks, or 1.4 MB disks showing only 1 MB free, occur only with 180 MHz and faster processor cards; system software 7.5.4 or the Power Mac Format Patch from the original disks cures it (SS p. 81).[1]
Drives and peripherals
[edit | edit source]| Symptom | Cures, in order | SS page |
|---|---|---|
| Floppy drive does not work, runs continuously, or ejects the disk with a blinking X | Try a known-good disk; replace the floppy cable, the drive, the processor card, the logic board | 69, 71 |
| Disk will not eject | Restart holding the mouse button; replace the cable, the drive, the processor card, the logic board | 70 |
| Single internal hard drive does not spin | Replace the drive power cable, the drive (then reinstall the driver and system), the power supply | 72 |
| No internal SCSI drive works | Check for duplicate SCSI IDs; disconnect external devices and check termination; replace the SCSI cable, the power supply, the processor card, the logic board | 72 |
| Drive does not appear on the desktop | Check SCSI IDs; update the driver with Drive Setup and run Disk First Aid; replace the cable; initialise; try a known-good drive; then replace the logic board | 73 |
| AppleCD 600i stutters on CD+ or CD-R discs, or a disc will not mount | Replace the CD-ROM drive | 79 |
| No sound from the speaker | Check the volume is 1 or above; clear PRAM and check the speaker is plugged into the logic board; replace the speaker, the logic board | 80 |
PCI card faults can come from residue on the card's edge connector; clean it with a pencil eraser (SS p. 54).[1] See Hard Drive Maintenance and Repair and Floppy Drive Repair.
Related pages
[edit | edit source]- Power Macintosh 8500
- Power Macintosh 8500 General Maintenance
- Power Macintosh 7500 Capacitor Replacement Guide
- Power Macintosh 9500 Troubleshooting
- Sad Mac Error Codes
- Capacitor Failure Symptoms
References
[edit | edit source]- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 Apple Computer, Service Source: Power Macintosh 8200 and 8500 Series/WS 8550 (1996), File:Powermac_8500_series.pdf; see Power Macintosh 8200 and 8500 Series/WS 8550 Service Source. Page numbers are PDF pages.
- ↑ 68k Macintosh Liberation Army forum, "Powermac 7500/100 dead" (2009): an 8500 with a dead PRAM battery that would not power up; suggestion to remove the battery and press the reset button near the processor card.
- ↑ 68k Macintosh Liberation Army forum, "PM/WS 8500 needs AV module to boot?" (2017), post by Bolle: an 8500 board would not start out of the case; the metal shielding at the back of the case connects the supply frame to the board's ground plane; it ran without the AV board.
- ↑ 68k Macintosh Liberation Army forum, "dead 8500" (2022).
- ↑ 68k Macintosh Liberation Army forum, "7500 Power Supply Woes" (2021): the 7500, 8500 and 9500 use the same supply connectors as the 7200, tested in practice.
- ↑ 68k Macintosh Liberation Army forum, "840AV dead PSU" (2024): an owner recapped an 8500/9500 supply and used it in a Quadra 840AV.
- ↑ 68k Macintosh Liberation Army forum, "8100 power on / off" (2023–2025): an 8100 board tried on a supply from an 8500; another owner has run an 8100 from a 9500 supply.