Interpreting POST Diagnostic Front Panel LEDs and Audible Codes

This section covers the front panel LED codes as well as the audible codes that may occur before or during POST that do not necessarily have an error code or text message associated with them.

WARNING! When the computer is plugged into an AC power source, voltage is always applied to the system board. To reduce the risk of personal injury from electrical shock and/or hot surfaces, be sure to disconnect the power cord from the wall outlet and allow the internal system components to cool before touching.

NOTE: If you see flashing LEDs on a PS/2 keyboard, look for flashing LEDs on the front panel of the computer and refer to the following table to determine the front panel LED codes.

Recommended actions in the following table are listed in the order in which they should be performed.

Not all diagnostic lights and audible codes are available on all models.

Table A-2Diagnostic Front Panel LEDs and Audible Codes

Activity

Beeps

Possible Cause

Recommended Action

 

 

 

 

Green Power LED On.

None

Computer on.

None

 

 

 

 

Green Power LED flashes

None

Computer in Suspend to

None required. Press any key or move the mouse

every two seconds.

 

RAM mode (some models

to wake the computer.

 

 

only) or normal Suspend

 

 

 

 

mode.

 

 

 

 

 

 

 

Red Power LED flashes two

2

Processor thermal

1.

Ensure that the computer air vents are not

times, once every second,

 

protection activated:

 

blocked and the processor cooling fan is

followed by a two second

 

A fan may be blocked or

 

running.

pause. Beeps stop after fifth

 

 

 

iteration but LEDs continue

 

not turning.

2.

Open hood, press power button, and see if

until problem is solved.

 

OR

 

the processor fan spins. If the processor fan

 

 

 

is not spinning, make sure the fan's cable is

 

 

The heatsink/fan

 

plugged onto the system board header.

 

 

 

 

 

 

assembly is not properly

3.

If fan is plugged in, but is not spinning, then

 

 

attached to the processor.

 

replace heatsink/fan assembly.

 

 

 

4.

Contact an authorized reseller or service

 

 

 

 

provider.

 

 

 

 

 

Red Power LED flashes three

3

Processor not installed

1.

Check to see that the processor is present.

times, once every second,

 

(not an indicator of bad

2.

Reseat the processor.

followed by a two second

 

processor).

pause. Beeps stop after fifth

 

 

 

 

iteration but LEDs continue

 

 

 

 

until problem is solved.

 

 

 

 

Red Power LED flashes four

4

Power failure (power

times, once every second,

 

supply is overloaded).

followed by a two second

 

OR

pause. Beeps stop after fifth

 

iteration but LEDs continue

 

The incorrect external

until problem is solved.

 

 

 

power supply adapter is

being used on the USDT.

1.Open the hood and ensure the 4 or 6-wire power supply cable is seated into the connector on the system board.

2.Check if a device is causing the problem by removing ALL attached devices (such as hard, diskette, or optical drives, and expansion cards). Power on the system. If the system enters the POST, then power off and replace one device at a time and repeat this procedure until failure occurs. Replace the device that is causing the failure. Continue adding devices one at a time to ensure all devices are functioning properly.

ENWW

Interpreting POST Diagnostic Front Panel LEDs and Audible Codes 55

Page 60 Page 62
Page 61
Image 61
HP dc7800 tower Table A-2Diagnostic Front Panel LEDs and Audible Codes, Activity Beeps Possible Cause Recommended Action
Page 60 Page 62

dc7800 tower specifications

The HP dc7800 Tower is a powerful desktop computer designed for professional and enterprise environments. Known for its stability, performance, and versatility, this model has secured its place in a variety of business settings. Launched in the mid-2000s, it embodies HP’s commitment to quality and innovation.

One of the main features of the HP dc7800 is its form factor. The tower configuration allows for easy upgrades and maintenance, providing ample space for additional hard drives, memory, and other components. This level of accessibility makes it ideal for businesses that need to adapt their systems to changing requirements.

The dc7800 is powered by Intel's Core 2 Duo processors, offering dual-core technology that enhances multitasking capabilities. With clock speeds ranging from 1.8 GHz to 3.0 GHz, this system can handle demanding applications with relative ease. It also supports Intel's vPro technology, which allows for remote management and security features, making it an excellent choice for organizations prioritizing IT control.

Another notable characteristic is the support for up to 8GB of DDR2 RAM. This allows for efficient data processing and improved performance when running multiple applications simultaneously. Additionally, the dc7800 features multiple storage options, accommodating both SATA hard drives and solid-state drives, which can significantly enhance boot times and overall system responsiveness.

Connectivity options on the HP dc7800 are robust. It includes a variety of USB ports, audio jacks, and optional legacy ports, ensuring compatibility with a wide range of peripherals and accessories. Networking capabilities are also prominent, with built-in Gigabit Ethernet providing high-speed internet access.

Furthermore, the desktop tower is designed with energy efficiency in mind. It meets ENERGY STAR certification standards, which not only helps reduce operational costs but also minimizes environmental impact.

Overall, the HP dc7800 Tower embodies a blend of performance, expandability, and energy efficiency, making it a reliable choice for businesses in need of a robust desktop solution. With its legacy of dependability and its suite of modern technologies, it continues to serve as a valuable asset in enterprise environments.
Top Page Image Contents