PowerBook (FireWire) I/O logic board, with the backup battery and power supply card connectors (Service Source, PDF p. 22)
Fault-finding on the PowerBook G3 Series (1998, Wallstreet), the PowerBook G3 Series (Bronze Keyboard) (1999, Lombard) and the PowerBook (FireWire) (2000, Pismo). Apple's symptom charts list cures in order of likelihood; try them in order, test after each, and refit the original part before moving on. They work at module level: logic board, processor board and the small power supply, sound and charge cards.[1][2][3] The 1997 PowerBook G3 follows PowerBook 3400c Troubleshooting and the PowerBook 3400c and PowerBook G3 Service Source. Disassembly is on PowerBook G3 General Maintenance.
Remove the top module and retest; replace the bottom module; then the processor board and I/O board[2][3]
Four or five beeps
Bad boot ROM checksum
The ROM is on the processor board; replace it[2][3]
Breaking-glass sound after the chime (1998 G3 Series)
RAM failure
Remove the top module and restart; replace the bottom module; replace the processor board, then the I/O board[1]
Four-tone error chord or hardware failure sound
External device, expansion module, drive, boards
Disconnect external devices; reset PRAM; remove each expansion bay module in turn; disconnect the hard drive; replace the drive connector board (1998) or drive cable, the drive, then the boards[1][2]
Boots only to a flashing question mark
Drive or cable fitted wrongly; firmware and system mismatch
mitchW found an SSD fitted with its IDE connector a row out on a Bronze Keyboard model.[4] DistantStar001's FireWire model, with updated firmware, would not boot Mac OS 9.1 but booted 9.2.1[5]
Intermittent failure to start, initialisation errors
Partly seated processor board; missing heatsink screw; dried thermal material
Check all heatsink screws; press the processor board home a second time; on the FireWire model check the black thermal material under the heat exchanger[2][3]
Crashes and "L2 cache" errors, cache missing from System Profiler (Bronze Keyboard)
Cracked solder under the processor or cache controller
mitchW reflowed both chips on the processor card and the cache returned[4]
Hung power manager; flat backup battery; adapter; boards
Press the reset button behind the I/O door, wait five seconds and press Power. Then try another adapter and a charged battery; connect the adapter and wait 3 to 4 minutes; disconnect the keyboard; reseat the processor board; then the sound card, power supply card, processor board and I/O board.[2][3] Owners report that a completely flat backup battery stops these machines starting, and that unplugging it brings them back[6][7]
Will not power up, or blank with the sleep LED lit (1998 G3 Series)
Backup battery power interrupted
Press Shift-Fn-Control-Power, wait five seconds, press Power; repeat three or four times. Then the adapter, battery, PMU cable, keyboard, processor board seating, sound card, power supply card, PMU card, I/O board and processor board[1]
Blank screen, no backlight, no response
Hung power manager; power sources; backup battery
Reset the power manager; restart; remove adapter and battery for 3 to 4 minutes; try another battery and adapter; remove all power and unplug the backup battery for ten minutes (two minutes on the 1998 model); check all logic board cables[1][2][3]
Repeated buzzing from the power board under the trackpad, no startup (Bronze Keyboard)
Power fault
Try a known-good adapter first; ikethederg's machine was not resolved[8]
Runs on the adapter but not on battery
Battery contact, shims, battery, charge or power supply card
Reset the power manager; reseat the battery; try it in the other bay; try a known-good charged battery; on the 1998 model check the battery shims; then the charge card (1998), PMU board, power supply card and I/O board[1][2][3]
Battery will not charge
Power manager; EMI shield against the adapter plug (1998); battery; charge or power supply card
Reset the power manager; try the other bay; on the Bronze Keyboard model insert and eject the battery four or five times, leaving it in for 15 seconds each time; on the 1998 model check that the right I/O wall EMI shield is not touching the adapter plug's outer shield; then a known-good battery and the boards[1][2]
Charges only when asleep or shut down
Wrong or weak adapter; EMI shield (1998)
Use the correct adapter; on the 1998 model check the EMI shield[1][2][3]
Settings lost when the battery and adapter are removed
Flat backup battery
Leave the adapter connected for 24 hours (a full recharge takes about 48); check the backup battery cable; replace the backup battery[1][2][3]
Battery lights blink
Battery fault; one blinking light means flat
Charge it; if more than one light blinks, the pack is faulty[3]
Apple's caution for all three: do not reseat the display cables with a metal screwdriver; use a plastic or nylon tool.[1][2][3]
Symptom
Probable cause
Action
Vertical lines, flicker or fading to white on a 13.3-inch 1998 G3 Series
Internal display cable
Apple replaced the display cable only; not the logic board or display[1]
Row of pixels always on or off
Display cable, display
Check the cable and connections; then the display cable and display[1][2]
Very light or white screen
Cables, inverter board
Check the display and inverter cables at the logic board; replace the inverter board, then the display cable and display[2]
No picture but the machine runs
Brightness, cables, inverter
Connect the adapter; turn up the brightness; check the display and inverter connections; try an external monitor; replace the inverter cable and board[2]
No backlight or very dim
Brightness, inverter cable and board, ageing lamp
Check the brightness, the backlight and inverter connections and the cables for pinching; replace the inverter board.[2] Owners report FireWire backlights dimming and slow to reach full brightness with age[7]
Dark screen after fitting a panel from a different model
Wrong inverter
Lombard and Pismo panels and inverters are not interchangeable[5]
Sleep light does not come on
Off rather than asleep; power manager; inverter board
Check it is asleep; reset the power manager; replace the inverter board[2][3]
Check that mute (F6) is off and the volume (F4) up; unplug headphones; reset PRAM; check the speaker cable at the sound card; replace the sound card, speakers and I/O board[2]
A row of keys stops working (FireWire)
Keyboard
Franklinstein reports this on FireWire keyboards[7]
Trackpad and button fade out after a few minutes (FireWire)
Unresolved
mdeverhart's machine kept the fault after a new drive and clean system; an external USB mouse worked[9]
↑ 4.04.168kMLA forum thread "PowerBook G3 Lombard L2 Cache Problem - Succefuly repaired!", mitchW, May 2026. IDE connector fitted a row out; crashes and an undetected L2 cache cured by reflowing the G3 and cache controller BGAs with flux and a heat gun at leaded-solder temperature. Community repair report.
↑68kMLA forum thread "G3 Pismo Dead in the water; Ideas?", Rick Dangerous, EvilCapitalist and PB145B, August 2019. A Pismo dead after storage; reset button behind the I/O door; unplugging a flat PRAM battery revived it. Community repair report.
↑ 7.07.17.268kMLA forum thread "Care and Feeding of a Pismo", Byrd, Franklinstein and others, February 2022. Dead PRAM batteries stop NewWorld PowerBooks booting, missing ones do not; the backup battery is charged only after the main battery reports full; failing keyboard rows and dimming backlights on the Pismo. Community experience.
↑68kMLA forum thread "PowerBook G3 Lombard power problems", ikethederg and others, March-December 2023. A Lombard that only buzzed from the power board under the trackpad; adapter substitution suggested; unresolved. Community report.
↑68kMLA forum thread "Pismo with Unresponsive Trackpad", mdeverhart and MacUp72, October 2023. Trackpad and button stop responding after a few minutes; persists after a new SSD and clean install; unresolved. Community report.
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