Power Macintosh 7100 Troubleshooting

Power Macintosh 7100 at the Apple Museum, Prague. Photo: Benoît Prieur, Wikimedia Commons, CC0

These are Apple's symptom charts for the Power Macintosh 7100, from the Power Macintosh 7100 Series Service Source. Apple lists cures in order of likelihood. Try the first, check whether the symptom persists, and refit the original module before trying the next (p. 35). The reset, battery and take-apart procedures named in the charts are on Power Macintosh 7100 General Maintenance.

Apple's troubleshooting tips

The manual's Basics chapter gives five points for every 7100 (pp. 6–8):

1. If the machine does not power up, reset the logic board before anything else.
2. Fit only noncomposite SIMMs, in pairs of the same size and speed.
3. Bad SIMMs do not produce death chimes; a dialog box reports a bad SIMM instead.
4. A hang soon after fitting a NuBus card usually means the card is not compatible with the Power Macintosh or needs newer software.
5. The AV models use the same logic board as the others, with the AV Card in the PDS. Every 7100 needs a card in the PDS: without one the machine may not boot or may crash.

Power and system

Power supply and system

Symptom	Apple's cures, in order
System does not power up	Reset the logic board; reseat the ROM SIMM and cache SIMM; replace the power supply; replace the logic board.
Does not power on; screen black, fan not running, LED not lit	Check the cables; plug the monitor straight into the wall and check it has power; reset the logic board; reseat the ROM and cache SIMMs; replace the power cord; replace the power supply; replace the logic board.
Clicking, chirping or thumping	Replace the power supply; replace the logic board, keeping the customer's SIMMs.
Shuts down intermittently	Check the air vents are clear (thermal protection can shut the system down; it should recover after 30 to 40 minutes); replace the power cord; check the battery; replace the power supply; replace the logic board.
Crashes or locks up intermittently	Check the system software is 7.1.2 or later; check the SIMMs are noncomposite and in like pairs; check the software is known-good and Power Macintosh compatible; check a video card is fitted in the PDS; clear PRAM (Command-Option-P-R at start-up, before "Welcome to Macintosh"); replace the cache SIMM if fitted; replace the DRAM SIMMs; replace the power supply; replace the logic board.

Source: pp. 36, 38–40.

Error chords

Error chords

Symptom	Apple's cures, in order
One-part error chord during start-up	Disconnect the hard drive's power and data cables and restart; if start-up is then normal, test the hard drive and replace it if needed. Disconnect the floppy cable and restart; if start-up is then normal, replace the floppy drive. Replace the logic board, keeping the customer's SIMMs.

Source: p. 37. Codes shown with a Sad Mac icon are decoded on Sad Mac Error Codes.

Video

Video

Symptom	Apple's cures, in order
Screen dark; audio and at least one drive work; fan running; LED lit	Adjust the monitor brightness; replace the video cable; try known-good RAM SIMMs; if the monitor is on the DB-15 port, move it to the HDI-45 port: if the problem goes away, check the VRAM SIMMs on the video card and replace them if bad, or replace the card if they are good; replace the monitor; replace the logic board.
Screen dark; audio and drives do not work; fan running; LED lit	Remove peripherals; remove NuBus cards; replace the DRAM SIMMs; replace the VRAM SIMMs; replace the video card; replace the power supply; replace the logic board.
Part or all of the screen bright, audio present, no picture	Replace the video cable; replace the VRAM SIMMs; replace the video card; replace the monitor; replace the logic board.
Screen completely dark, fan not running, LED not lit	Check the external power cables; reset the logic board; remove peripherals; remove NuBus cards; replace the power supply; replace the logic board.
Multiple Scan monitor on a 7100/66AV shows ghosting or smearing	Replace the Power Macintosh AV Card.

Source: pp. 41–43. Apple's chart uses the DRAM-based HDI-45 port on the logic board to check the PDS card and its VRAM (pp. 27, 41).

Floppy drive

Floppy drive

Symptom	Apple's cures, in order
Audio and video present, floppy drive does not work	Replace the floppy drive cable; replace the floppy drive; replace the logic board.
Disk ejects and the screen shows a Mac icon with a blinking "X"	Try another disk; replace the floppy cable; replace the floppy drive; replace the logic board.
Disk will not eject	Switch off and hold the mouse button while switching on; eject the disk manually; replace the floppy cable; replace the floppy drive.
Drive tries to eject but the disk stays in	Push the disk fully in; eject it manually; replace the floppy drive; reseat or replace the top housing.

Source: pp. 44–45. See Floppy Drive Repair.

Hard drive and CD-ROM

Hard drive and CD-ROM drive

Symptom	Apple's cures, in order
Hard drive runs continuously	Update the drive's driver with HD SC Setup; reinstall the system software; replace the SCSI data cable; replace the hard drive; replace the logic board.
Hard drive does not work	Replace the SCSI data cable; replace the SCSI power cable; replace the hard drive; replace the logic board.
CD-ROM drive will not accept a disc	Try a clean, undamaged disc; replace the CD-ROM mechanism.
No CD-ROM icon on the desktop	Check the CD-ROM extension is in the System Folder; replace the CD-ROM mechanism; replace the SCSI data cable.
Disc will not eject	Turn off file sharing in the Sharing Setup control panel; eject the disc manually; press the eject button behind the front bezel if you can reach it; replace the CD-ROM mechanism.

Source: pp. 46–47. See Hard Drive Maintenance and Repair.

Peripherals

Peripherals

Symptom	Apple's cures, in order
SCSI device works on its own (internal or external) but not with both	Replace the external SCSI cables; make sure there is only one terminator on the external devices; make sure no external device shares an internal device's SCSI ID; make sure the hard drive is terminated and the CD-ROM drive is not; replace the terminator on the external device; replace the external device's SCSI select cable.
Cursor does not move	Restart; check the mouse connection; if the mouse was on the keyboard, connect it to the computer's ADB port and replace the keyboard if it then works; replace the mouse; replace the logic board.
Cursor moves but clicking has no effect	Replace the mouse; replace the logic board; try the mouse on the computer's ADB port and replace the keyboard if that works.
Double-click does not open an application, disk or server	Remove duplicate System files; clear PRAM; try the mouse on the computer's ADB port; replace the mouse; replace the logic board.
No response to any key	Check the keyboard is on the ADB port; replace the keyboard cable; replace the keyboard; replace the logic board.

Source: pp. 48–50.

Memory

Memory

Symptom	Apple's cures, in order
About This Macintosh reports more memory than is fitted	Check the SIMMs are in matching pairs; replace the SIMMs.
About This Macintosh reports less memory than is fitted	Check the SIMMs are in matching pairs; replace the SIMMs.

Source: p. 51. Low End Mac reports that the 7100 does not recognise more than 32 MB per SIMM, even with 64 MB SIMMs fitted.

Capacitors

Apple's charts treat the power supply and logic board as modules. The logic board uses surface-mount tantalum capacitors; Console5's list for board 820-0597-A and the replacement procedure are on Power Macintosh 7100 Capacitor Replacement Guide.

Related pages

• Power Macintosh 7100
• Power Macintosh 7100 General Maintenance
• Power Macintosh 7100 Capacitor Replacement Guide
• Power Macintosh 6100 Troubleshooting