Apple eMac User Manual

10 - eMac  Troubleshooting
 General Information
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...

eMac  Troubleshooting - 11
 General Information
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...

12 - eMac  Troubleshooting
 General Information
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 (on the service module) by 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...

eMac  Troubleshooting - 13
 General Information
Procedure
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...

14 - eMac  Troubleshooting
 General Information 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
4.  If y
ou 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.
5. Remove the LHR from the faulty display/analog...

eMac  Troubleshooting - 15
 General Information
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...

16 - eMac  Troubleshooting
 General Information 2. Carefully clean the surface of the microprocessor with a plastic stylus or nylon probe tool (922-5065) to 
remove the old thermal paste. 
3.
Squeeze a drop of thermal paste onto the middle of the microprocessor as shown. 

eMac  Troubleshooting - 17
 General Information 4. Spread the paste evenly over the processor. 
5. Reinstall the heatsink. 

18 - eMac  Troubleshooting
 General Information
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...

eMac  Troubleshooting - 19
 Symptom Charts
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...