Powerbook Logic Board

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The PMU Chip

The PMU (Power Management Unit) is a micro controller chip that controls all power functions for the computer. The PMU is a computer within a computer. It has memory, software, firmware, I/O, two crystals, and a CPU. Its function is to:

  • Tell the computer to turn on, turn off, sleep, wake, idle, etc.
  • Manage system resets from various commands.
  • Maintain parameter RAM (PRAM).
  • Manage the real-time clock.

Important: The PMU is very sensitive and touching the circuitry on the logic board can cause the PMU to crash. If the PMU crashes, the battery life goes from about five years to about two days if the PMU is not reset. Refer to the next topic, "Resetting the PMU on the Logic Board" for the procedure.

Many system problems can be resolved by resetting the PMU chip. The PMU reset button is located behind the user access door, refer to the graphic below.

Pmu Apple Emac

Location of the PMU Reset Button

Resetting the PMU on the Logic Board

Resetting the PMU (Power Management Unit) on the logic board can resolve many system problems. Whenever you have a unit that fails to power up, you should follow this procedure before replacing any modules.

  1. Save open documents and quit all open applications.
  2. Turn the computer off by choosing Shut Down from the Special menu (if using Mac OS 9), or choose Shut Down from the Apple menu if using OS X.
  3. Remove the user access door.

4 Unplug all cables, except the power cord, from the computer.

5 Touch a metal surface inside the computer. Then unplug the power cord.This helps protect the computer from damage caused by electrostatic discharge. Important: To avoid electrostatic discharge, always ground yourself by touching metal before you touch any parts or install components inside the computer. To avoid generating static electricity, do not walk around the room until you have finished the procedure and closed the computer.

Static Electricity Damage Chip

6 Press the PMU reset button (shown below) once and then proceed to step 7. Do NOT press the PMU reset button a second time because it could crash the PMU chip.

Pmu Reset Button

7 WAIT ten seconds before connecting the power cord and powering the computer on. If the computer powers on, go to the next step. If the computer does not power on, there is something else wrong with the computer, refer to the symptom/cure, "No Power" in this chapter.

8 Run MacTest Pro and return the computer to the customer.

Note: This entire procedure resets the computer's PRAM. Be sure to reset the computer's time, date and other system parameter settings before returning the computer to the customer.

Power-On Self Test

There is a power-on self test that resides in the ROM of the eMac. This test automatically runs whenever the eMac is powered on after being fully shut down (the power-on self test does not run if the machine is only restarted).

If a problem is detected during the test, you will not hear a normal startup chime. Instead, the system will beep as explained below. Refer to "Error Beeps" later in this chapter for instructions on how to troubleshoot and repair an eMac that sounds error beeps at startup time.

Following is a definition of what the error beeps at startup time signify. One Beep: No RAM is installed or detected.

Two Beeps: Incompatible memory is installed. (The slots accept standard PC-100 or PC-133, 168-pin DIMMs).

Three Beeps: No RAM banks passed memory testing.

Four or Five Beeps: Bad checksum for the remainder of the boot ROM. The ROM is bad.

Logic Board Battery

Important: Apple highly recommends removing the battery when handling the logic board. Make sure to use proper ESD protection when handling modules.

The battery on the logic board controls the stored system settings, such as date and time. It is only necessary to test the battery when you can't power on the computer, or the date and time are reset every time the AC power is removed.

The battery is also used to power the PMU chip (because the PMU chip keeps time and must always be running) when the computer is unplugged from the wall (AC power). The PMU is very sensitive and touching any circuitry that is connected to the PMU can cause it to crash. If the PMU crashes, the battery life goes from about five years to about two days if the PMU is not reset. Once the battery goes dead, the PMU will reset the time and date every time the AC power is removed. To fix this situation, replace the battery and reset the PMU (refer to "Resetting the PMU on the Logic Board" mentioned earlier in this chapter).

Testing the Battery

If the computer has a "No Power" situation, check the battery before replacing modules. A drained battery may be indicative of a crashed Power Management Unit.

With the battery in the battery holder (under load), measure the voltage across the battery's positive and ground terminals.

With the battery in the battery holder (under load), measure the voltage across the battery's positive and ground terminals.

Reset Button Pram Battery Emac

Does the battery measure at least +3.5v? If not, replace the battery and reset the PMU. If the battery does measure over +3.5v, reinstall the battery and reset the PMU as above

Connect the power cord and power up the system again.

Display/Analog Voltage Setting and LHR Module Instructions

The display/analog assembly contains a non-switching power supply which is preset at a 220V configuration.The voltage selection needs to be manually set by the way of a voltage jumper. This means if you are operating the computer in a 110V environment, you will have to install the voltage jumper.

The following instructions explain how to configure the voltage and LHR jumpers on the digital/analog assembly. Note: The LHR (a line conditioning module) is required in some international countries.

Refer to Table 1 for jumper settings and refer to Figures1, 2, and 3 for jumper and LHR locations. Tools

This procedure requires the following tools:

  • needlenose pliers to remove/attach the voltage jumper
  • phillips #2 screwdriver if attaching the LHR module
Table 1: Jumper Settings

Voltage Environment

Voltage Jumper Setting

LHR Jumper Setting

110 V

Jumper is on

no LHR module

Jumper is off

with LHR module

Jumper is off

1. Locate the voltage jumper circled below in Figure 1. Note: this jumper won't be installed on a 220V computer. Next, refer to Table 1 (on the previous page) for the voltage jumper setting and set the jumper accordingly. Warning: Be careful around the CRT. Discharge the CRT before removing or replacing the jumper.

Figure 1: Voltage Jumper Locator

2. Locate the LHR coil jumper circled in Figure 2. Then refer to Table 1 for the LHR jumper setting and set the jumper accordingly.

Figure 2: LHR Jumper Locator

3. Identify if you have the LHR coil (Figure 3) on the eMac. Note: The LHR coil (a line conditioning module) is required in some international countries.

Figure 3: LHR Module Locator
  1. If you don't have an LHR module, install the replacement display/analog assembly and ensure the jumpers are set correctly. If you have an LHR, go on to step 5.
  2. Remove the LHR from the faulty display/analog assembly, place the LHR on the replacement digital/ analog assembly, and set the jumpers according to Table 1.

Thermal Paste Application

The microprocessor uses a heatsink/thermal pipe to transfer heat away. Whenever the heatsink is removed, the bottom side of the heatsink and the top of the microprocessor must be cleaned and thermal paste must be applied. If the mating surfaces are not cleaned and thermal paste is not applied, the CPU may overheat and become damaged.

Tools

This procedure requires the following tools:

  • Plastic stylus or nylon probe tool (922-5065) to remove the old thermal paste
  • Thermal paste (922-4757), each tube contains 4-5 applications

Procedure

1. Thoroughly clean the thermal film from the heatsink surface with a plastic stylus or the nylon probe tool. Do not use an abrasive material or liquid cleaner. Important: Be extremely careful not to bend the heatpipes on the heatsink.

Gluing Probe Heat Sink

2. Carefully clean the surface of the microprocessor with a plastic stylus or nylon probe tool (922-5065) to remove the old thermal paste.

Microprocessor Images For Older
3. Squeeze a drop of thermal paste onto the middle of the microprocessor as shown.
Thermal Material Microprocessor
4. Spread the paste evenly over the processor.

CRT Neck/Display/Analog Assembly Handling Information

Handling

Important: It is imperative that proper handling and packaging guidelines be followed when working with the display/analog assembly.

Do NOT lift, handle, bump, or manipulate the CRT neck/neck board (see red arrows below) on the Display/ Analog assembly. Modules damaged by mishandling are NOT covered by Apple Warranty. Apple Authorized Service Providers can be liable for broken CRT necks due to improper handling.

Caution: The metal chassis has sharp edges, you may want to wear gloves when handling the assembly. Lift the assembly from the metal chassis; never lift the assembly from the neck. I

Packing a Defective Display/Analog Assembly

The packing procedure is included with the replacement display/analog assembly. Incorrect packaging can result in damaged eMac displays. Please read and follow the directions enclosed in the shipping box of the new display prior to packaging the defective assembly. AASPs can be liable for broken CRT necks due to improper packing and handling.

Emac Lhr Line Conditioning Coil

Symptom Charts

How to Use the Symptom Charts

The Symptom Charts included in this chapter will help you diagnose specific symptoms related to the product. Because cures are listed on the charts in the order of most likely solution, try the cures in the order presented. Verify whether or not the product continues to exhibit the symptom. If the symptom persists, try the next cure.

Note: If you have replaced a module, reinstall the original module before you proceed to the next cure.

Apple Hardware Test

Apple Hardware Test is a diagnostic tool for detecting problems with Apple internal hardware components such as logic board, memory, modem, video RAM, and Apple AirPort Card. The test does not check externally connected hardware components such as USB or FireWire devices; it also does not check nonApple devices such as third-party PCI cards.

Note: The most recent Apple Hardware Test software can be downloaded from the CD Images page on AppleCare Service Source; go to the Service Source home page and select 'Disc Images' from the quick-click table.

Error Codes

If Apple Hardware Test detects a problem with a computer, it displays an error code, which is defined in the product's Error Code List. Consult the list for appropriate repair procedures associated with the code.

All Error Code Lists are included in the Service Diagnostics Matrix, Knowledge Base article 112125. You can also access this matrix by clicking the Service Diagnostics rollover link under any of the product areas on the Service Source home page.

No Power

The computer will not power on.

  1. Verify the power outlet is good. Plug a different device into the socket to ensure there is power, or plug computer into another outlet.
  2. Check the power cord. Use a known good power cord.
  3. Check connection of the power cord on both ends. Verify that the plug is securely plugged into both the A/C outlet and back of the computer.
  4. Remove keyboard, mouse, and other peripherals such as speakers.
  5. Position the computer so it rests on the CRT face.
  6. Remove the user access door.

7 Touch a metal surface inside the computer.

7 Touch a metal surface inside the computer.

8 Unplug the unit.

9 Verify the battery is good before replacing modules. A drained battery may be indicative of a crashed Power Management Unit. Does the battery measure at least +3.5v? If not, replace the battery and reset the PMU.

  1. Reset PMU. Refer to "Resetting the PMU on the Logic Board" mentioned earlier in this chapter.
  2. Remove the rear housing.

Warning: This product contains high voltage and a high-vacuum picture tube. To prevent serious injury:

  • Review the CRT safety information on Service Source online.
  • Discharge the CRT
  • Never use a grounding wriststrap until after discharging the CRT and setting up an ongoing ground connection.
  1. Check the power button. Attach a known good power button to the unit. Do you have power now? If yes, replace the power button. If no, go to the next step.
  2. Unplug the unit. Warning: Make sure the ground screw (see below) is attached to the frame when testing power.
  3. Unplug the unit. Warning: Make sure the ground screw (see below) is attached to the frame when testing power.
Apple Emac 110v Convert 220v
14. Check the AC connector. Make sure it's connected. Do you have power now? If yes, test the unit and return it to the customer. If no, go to the next step.
Emac Crt Fuse

15. Warning: Make sure the computer is unplugged. Check the fuse (see graphic below).You will need an ohm meter to do a continuity test on the fuse. Using an ohm meter, touch the red and black probes to the two metal points at location F901 and check for continuity (reading of "0"). If the ohm meter registers "0", the fuse is good. If the meter registers "infinite", the display/analog assembly should be replaced.

16. Plug the unit in. Check for AC voltage (see below). Warning: Do not force the probes into the connector. Doing so could break the connector. Do you measure 120V (line voltage)? If yes, go on to the next step. If no, replace the display/analog assembly.

Emac Analogue Board Voltages

17. Make sure the computer is plugged in. Check for 5V trickle on capacitor C3202 (located near the modem board) on the logic board (see graphic below). Do you get 5 V? If yes, go to the next step. If no, replace the display/analog assembly.

18. Check the down converter connector. Verify that it is properly connected.

Imac Down Converter

19. Plug the unit in, but don't press the power button. Check the down converter. Be extremely careful when checking voltages. It is easy to short between the pins. Ground to the frame with the black probe and check pin 1 on P801 with the red probe. A reading of 10.5V up to 17.5V is acceptable. If you get a reading in that range, replace the display/analog assembly. If not, replace the logic board.

Powerbook Logic Board Pad Fuse

Random Shut Down

While using the computer it just shuts down for no reason.

1. Check the jumper settings, make sure they are set correctly. Refer to the "Digital/Analog Voltage Setting and LHR Module Instructions" mentioned earlier in this chapter. Note: There is one jumper for the voltage and one jumper for the LHR coil. Both jumpers should be installed when the computer is operating in the 110V environment. If the jumpers are set correctly, refer to "No Power".

Emac 110 220
Voltage Jumper Location
The Dimm Voltage Jumpers Ram
LHR Coil Jumper Location

No Video

No video to the internal display, the fan is spinning, there is drive activity

  1. Reset parameter RAM. Press Command-Option-P-R during startup.
  2. The system software could be damaged. Start up from the system CD that came with the computer.
  3. Remove the user access door.

4 Touch a metal surface inside the computer.

4 Touch a metal surface inside the computer.

  1. Disconnect the A/C power cord. Press the PMU reset button on the logic board. Refer to "Resetting the PMU on the Logic Board" mentioned earlier in this chapter.
  2. Check for external video. Connect an external monitor to the video out port. Did you get external video? If yes, replace the display/analog assembly. If no, go on to the next step.
  3. Replace the main logic board.

Vertical Raster Shift

The raster moves up to the point where the menu bar is no longer visible. Replace the IVAD cable (922-5806). Follow the procedure below.

Tools

This procedure requires the following tools:

  • 2.5 mm hex tool
  • Phillips #2 screwdriver
  • Hot-melt glue gun (recommended)
  • Nylon probe tool (922-5065)

Procedure

  1. Remove the rear housing from the eMac.
  2. Discharge the CRT. Warning: This product contains high voltage and a high-vacuum picture tube. To prevent injury, review the Service Foundations course: "CRT Displays" for safety information.
  3. Locate the IVAD assembly shown below.
Ivad Access

4. Note: The screws on IVAD assembly need to be removed to access one end of the IVAD cable. Remove the screw (circled below) and then remove the metal cable cover.

Emac Repair

5. Remove the remaining two screws on the IVAD assembly.

With the nylon probe tool or needlenose pliers, remove the glue from the connector. Note: If you find it difficult removing the glue use a heat gun to soften the glue a bit and then remove it. Disconnect the cable after removing the glue.

Packard Connector Pliers Mac Tools

8. With the nylon probe tool or needlenose pliers, remove the glue from the cable connector. Note: If you find it difficult removing the glue use a heat gun to soften the glue a bit and then remove it.

Ivad Placement

IVAD Cable Replacement Procedure

  1. Install the replacement IVAD cable.
  2. Replace the cable tie (shown on the previous page).
  3. Place hot glue on each end of the IVAD connector.
  4. Reassemble the computer and test the system.

Mass Storage

Flashing question mark appears on the screen

  1. Boot from the system CD that came with the computer and see if the hard drive mounts on the desktop.
  2. Launch Drive Setup and update the hard drive driver.
  3. If no hard drive is found in Drive Setup, verify the hard drive cable connections.
  4. Replace the hard drive cable.
  5. Reinstall the software drivers for the hard drive.
  6. Reinstall system software. Note: Backup the data first.
  7. Reinitialize the hard drive.
  8. Replace the hard drive.
  9. Replace the logic board.

Alternating flashing question mark and a flashing Mac OS face on a folder.

  1. This symptom could indicate damaged system software or non-compatible system software. Boot from the system CD that came with the computer and see if the hard drive mounts on the desktop.
  2. Launch Drive Setup and update the hard drive driver.
  3. If no hard drive is found in Drive Setup, verify the hard drive cable connections.
  4. Replace the hard drive cable.
  5. Reinstall the software drivers for the hard drive.
  6. Reinstall system software. Note: Backup the data first.
  7. Reinitialize the hard drive.
  8. Replace the hard drive.
  9. Replace the logic board.

Hard drive spins, but won't mount to the desktop

  1. Disconnect any connected peripherals.
  2. Boot from the system CD that came with the computer and see if the hard drive mounts on the desktop.
  3. Launch Drive Setup and update the hard drive driver.
  4. If no hard drive is found in Drive Setup, verify the hard drive cable connections.
  5. Replace the hard drive cable.
  6. Replace the hard drive.
  7. Replace the logic board.

Hard drive does not spin.

  1. Disconnect any connected peripherals.
  2. Boot from the system CD that came with the computer and see if the hard drive mounts on the desktop.
  3. Launch Drive Setup and update the hard drive driver.
  4. If no hard drive is found in Drive Setup, verify the hard drive cable connections.
  5. Replace the hard drive cable.
  6. Replace the hard drive.
  7. Replace the logic board.

System hangs during normal startup process

  1. Boot from the system CD that came with the computer and see if the hard drive mounts on the desktop.
  2. Using Drive Setup, reinstall the system software drivers for the hard drive.
  3. Using Drive Setup, reinitialize the hard drive.
  4. Check all cable connections to and from the hard drive.
  5. Replace the hard drive cable.
  6. Replace the hard drive.
  7. Replace the logic board.

CD or DVD tray won't open

  1. Check for obstructions on the optical drive door.
  2. Replace the optical drive cable.
  3. Replace the optical drive.
  4. Replace the logic board.
  5. Replace the down converter.

Optical drive won't accept a CD or DVD

  1. Check for obstructions on the optical drive door.
  2. Replace the optical drive cable.
  3. Replace the optical drive.
  4. Replace the logic board.
  5. Replace the down converter.

CD or DVD disc constantly ejects at startup

  1. Try cleaning the disc. If it is dirty or scratched, it may not mount.
  2. Try a known good disc.
  3. Disconnect all peripheral devices, especially the mouse in cases where the disc is constantly ejecting. This symptom may be an indication of a failed mouse giving a signal that the mouse is stuck in the down position. Try a known good mouse.
  4. Boot from Apple Hardware Test (hold down the "C" key at startup) or boot from the system install CD (use Startup Manager, hold down the Option key at startup).
  5. Perform a clean install with the CD that came with the computer.
  6. Replace the optical drive cable.
  7. Replace the optical drive.
  8. Replace the logic board.

Optical drive doesn't spin

  1. Replace the optical drive cable.
  2. Replace the optical drive.
  3. Replace the logic board.
  4. Replace the down converter.

CD or DVD won't mount to the desktop

  1. Try cleaning the disc. If it is dirty or scratched, it may not mount.
  2. Try a known good disc.
  3. Refer to the "Flashing Question Mark" symptoms mentioned in this section.
  4. Boot from Apple Hardware Test (hold down the "C" key at startup) or boot from the system install CD (use Startup Manager, hold down the Option key at startup).
  5. Perform a clean install with the CD that came with the computer.
  6. Replace the optical drive cable.
  7. Replace the optical drive.
  8. Replace the logic board.

Sound Out

No sound from either internal or external speakers

  1. Verify volume setting is correct in system preferences.
  2. Verify the computer is not set to "mute". Press the mute key on the Apple keyboard.
  3. Reset parameter RAM. Press Command-Option-P-R during startup.
  4. Test the computer with known-good headphones. Do you get sound? If yes, go on to step 4. If no, replace the main logic board.
  5. Verify that the speaker cable is connected.
  6. Replace the speaker assembly.
  7. Replace the logic board.

No sound from the headphones

  1. Verify the problem with known-good headphones.
  2. Verify the computer is not set to "mute". Press the mute key on the Apple keyboard.
  3. Verify volume setting is correct in Mac OS X system preferences. If the preferences are set correctly, replace the logic board.
  4. In Mac OS 9, check the Sound Control panel, Speakers tab. When headphones are connected, a headphone icon will be present. If the headphone jack is malfunctioning it may indicate that headphones are connected when none are connected. In this case, replace the logic board.

Sound In

No sound is recorded

  1. Check setup of the system preferences for the microphone.
  2. Check that the microphone is picking up sound by testing the audio in iMovie. Click on the Audio button. Record something. The audio bar on the screen should indicate if the microphone is working.
  3. Check the microphone cable connection.
  4. Replace the internal microphone.
  5. Replace the main logic board.

Error Beep(s) Computer beeps at startup.

  1. RAM expansion DIMMs for the eMac must be PC133 compliant and use SDRAM devices. If the user installs a DIMM that uses EDO or SGRAM devices, the computer will beep several times when the user attempts to restart the computer.
  2. Refer to "Power-On Self Test" mentioned earlier in this chapter.

Modem

No modem dial tone

  1. Verify known-good analog (not digital) telephone line.
  2. Verify known-good RJ-11 telephone cable.
  3. Verify RJ-11 cable is not plugged into Ethernet port.
  4. Inspect RJ-11 connector and modem port for pin damage.
  5. Verify RJ-11 cable is firmly installed in the modem port.
  6. Verify correct modem driver is installed and the correct CCL is selected. If the problem persists, reinstall system software.
  7. Open the bottom housing. Verify the internal RJ-11 modem cable is connected to the modem.
  8. Replace the RJ-11 cable/ jack.
  9. Replace the modem.
  10. Replace the logic board.

USB Printing Problems eMac cannot print to attached known-good printer.

  1. Verify that the printer is Macintosh compatible.
  2. Verify that you have setup the printer correctly in OS X.
  3. Refer to Knowledge Base article 106714, Mac OS X: How to Print
  4. Reinstall the printer driver.
  5. Switch the printer to another USB port.
  6. Replace the printer interface cable.
  7. System software is corrupted. Reinstall the system software.
  8. Replace the logic board.
DIY Battery Repair

DIY Battery Repair

You can now recondition your old batteries at home and bring them back to 100 percent of their working condition. This guide will enable you to revive All NiCd batteries regardless of brand and battery volt. It will give you the required information on how to re-energize and revive your NiCd batteries through the RVD process, charging method and charging guidelines.

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Responses

  • How to fix ibook display not fonction?
    8 years ago
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    Which tool is recommended to remove the microprocessor?
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    How to reset the pmu on emac what keys to hit?
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    Where is the pmu button emac?
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