PowerBook 3400c General Maintenance

PowerBook 3400c (Neale Monks, Wikimedia Commons, CC BY-SA 3.0)

Care and preventive work for the PowerBook 3400c. Apple's procedures come from the PowerBook 3400c/PowerBook G3 Service Source, which also covers the first PowerBook G3 built in the same case.

Before opening the machine

• Unplug the adapter and remove the battery before any take-apart: push the button and slide the battery out of the bay. Refit the battery before reconnecting the adapter.
• Tools Apple lists: a small flat-blade screwdriver, T-8 Torx for most screws, T-6 Torx for the floppy drive, a swizzle stick for name plates and kapton tape, and a dental pick for opening flex connectors.
• There are 38 screws in 12 sizes, but each part uses only one type, which makes reassembly simpler.

Batteries

Main battery

The 3400c uses a lithium-ion battery rated for 2-4 hours; Apple's specification page gives it as 32 Wh. A NiMH battery was an option, with less running time. Tell them apart by the label, or by the charge indicator lights, which only the lithium-ion pack has. A 3400c battery fits a 5300 or 190 but is not recognised or charged there.

Apple gives no voltage test for this battery: press the level indicator button and read the lights, which show full, three-quarters, half or a quarter. Apple's handling rules:

• Do not leave a battery in the computer for more than a week without the adapter connected.
• Keep the cap on a battery that is out of the computer.
• Do not leave it somewhere hot, and do not store it for more than six months without recharging.
• Never get it wet or short its terminals; Apple warns a short can cause an explosion or fire.
• Recharge it only as the owner's manual describes, in a ventilated place.

One owner who fitted new cells to a 3400c pack lost its control board in the process; with 16.8 V applied to the pack's front contacts and the check button pressed, all five indicator lights came on. See Battery Refurbishment and Battery Explosion, Capacitor or Corrosion Damage.

If a machine running on battery shuts down when it is moved or pressed near the battery, Apple's fix is a foam gasket in the battery bay (kit 076-0706). Put it on the notched side of the bay, on the dull grey surface and not the shiny metal above it, line its angled edge up with the notch, and burnish it down with the back of the applicator.

Backup battery

The backup battery is a 60 mAh rechargeable NiMH pack (part 922-2692) that keeps the clock, and the contents of RAM for a few minutes while the main battery is changed in sleep. MacDat lists the 3400c among laptops whose NiMH backup packs leak; one owner found a 3400c/200 pack beginning to leak at its connector, and another lost a power distribution board to electrolyte that wicked along the battery wire. Remove it from any 3400c you keep.

It is stuck with reusable adhesive to the underside of the brightness and speaker grill. To reach it, remove the battery, the floppy or CD-ROM drive and the keyboard; unplug the brightness and speaker cable with a dental pick, remove the grill's screw and lift the grill off; then unplug the backup battery and peel it off the grill. A replacement must go in exactly the same place, or the grill will not align.

Apple's check: set the date and time, shut down, remove the main battery and adapter for ten minutes, then reconnect and switch on. If the date and time are lost, leave the machine plugged in for 48 hours to recharge the backup battery, and replace it if it still fails.

Power adapter

Apple gives no test for the 3400c adapter; its instruction is to try a new adapter if the computer will not run from the existing one. The adapter is 45 W. Low End Mac gives the part numbers as M4896 or M4895.

Resetting PRAM and the power manager

The procedure is the same as on the PowerBook 5300:

1. Unplug the adapter, press the power key and immediately hold Option, Command, P and R until the startup chime sounds at least once more. These machines often chime only once, then the screen goes dark and the green sleep light stays on.
2. Press the reset button once; the machine should start. If the light stays solid green, press reset again or start with the power key.
3. Shut down and plug in the adapter. If the machine stays off, the reset worked. If it switches itself on, reset the power manager: remove the battery, unplug the adapter, hold the reset button for one minute, then reconnect the adapter.

If the sleep light is on continuously and the machine will not start, hold the reset button for 10-20 seconds, three or four times if needed.

Keyboard and display

To remove the keyboard, take out the battery and the floppy or CD-ROM drive, close the computer and remove the three bottom screws. Open it and lift the keyboard slightly up and towards you with a flat blade until you feel resistance; pulling further tears the keyboard cables out. Turn it onto the palm rest, ease the backup battery wires out of their two catches on the PCMCIA insulator so they clear the right-hand connector, and lift the keyboard cables off with a dental pick. A foam gasket (922-3103) belongs on the bottom of the keyboard.

Apple's notes on the display:

• Display cables on some machines worked loose from the logic board, leaving no picture or backlight. The cure is a brightness and speaker grill (922-2488) with the foam gasket that holds the connector down. If the grill is missing its gasket, replace it.
• Set the display at 170 degrees to remove the clutch covers, and fit the palm rest before the covers.
• When refitting the display assembly, line up the screw hole in the display cable with the hole in the clutch, or the cable will tear. If a floppy disk then slides between the closed lid and the top case, Apple's note calls the clutch screws "undertightened" and says to remove the display and loosen them.
• Inside the lid, the display cable wraps round the right clutch and its "Y" section is held by kapton tape, which Apple reattaches. The four pieces on the display shield flaps are thrown away and replaced with new tape, because kapton tape sticks to itself and to aluminium. Avoid pressing on the display when working on the inverter, or the screen can crack.

Display assembly with part numbers, including the display/inverter cable 922-2467 and clutch and sleeve 076-0645 (Service Source, PDF p. 210)

Hard disk and expansion bay

The internal drive is a 2.5-inch ATA disk. It sits in a bracket held to the CPU stiffener by three screws, under the keyboard, grill, clutch covers and palm rest; lift the bracket only until you feel resistance, because the drive cable is still plugged into the logic board near the middle of the bracket. With the drive out, the machine is top-heavy: rest the battery across the bottom right corner or set the display at about 80 degrees so it does not tip back. Original IBM Travelstar drives can stick and make siren-like noises at startup. Low End Mac warns that the drive controller in pre-G4 PowerBooks does not work with some ATA-6 (Ultra ATA/100) drives. See Hard Drive Maintenance and Repair.

Capacitors

The logic board has one electrolytic capacitor, the DC power board two, and the Sharp display and the inverter board two each. Values are on PowerBook 3400c Capacitor Replacement Guide.

Preventive checklist

1. Remove the backup battery from under the speaker grill and check the area for leakage.
2. Check the main battery with its indicator lights and inspect it for damage before charging.
3. Check that the brightness and speaker grill has its foam gasket over the display cable connector.
4. Check the battery bay gasket if the machine cuts out on battery.
5. Back up or replace the original hard disk.

Related pages

• PowerBook 3400c
• PowerBook 3400c Troubleshooting
• PowerBook 3400c Capacitor Replacement Guide
• PowerBook 3400c and PowerBook G3 Service Source