Video and Sound Troubleshooting

Video and sound are certainly two of the most exciting aspects of the PC. New video systems promise high performance, with resolutions and color depths that simply weren't practical a few years ago. Enhanced video systems even provide support for features like a video conferencing and MPEG video playback. Today's sound boards offer symphonic sound with MIDI and wave table synthesis. Taken together, video and sound supply the backbone of a computer's multimedia capabilities. Still, the advances in video and sound have not come without price-namely, the demand for computing power. In addition, advanced chipsets and their drivers are sometimes incompatible with PC configurations. This chapter looks at background and troubleshooting for video and sound system.

Video Adapters


The conventional frame buffer is the oldest and best-established type of video adapter. The term frame buffer refers to the adapter's operation-image data is loaded and stored in video memory one "frame" at a time. Frame buffer architecture has changed very little since PCs first started displaying text and graphics. A typical frame buffer video board is composed of four major seconds:

• CRTC (cathode-ray-tube controller). A highly integrated controller which generates control signal and manages the video adapter's operation. The functions of the CRTC are now normally handled by video chipsets.
• VIRAM (video RAM). An amount of RAM used to hold to store image data which is processed and passed to the monitor.
• Character ROM. A relatively small ROM used to hold the dot patterns of text characters. The character ROM is disabled while the video adapter is in the graphics mode.
• Video BIOS. A ROM used to hold the low-level instructions needed to operate the video board. All video adapter from EGA onward use video BIOS in one form or another.

Video troubleshooting

Symptom 1: The computer is on, but there is no display (the PC seems to initialized properly). In most cases, there is a problem with your monitor or video board instillation.

• Check the beep codes. If there are a beep codes during initialization, the video adapter may be defective or installed incorrectly. Now what is beep codes? Beep Codes - each time PC initializes, BIOS executes a series of test collectively known as the power-on self-test (or POST). The POST checks each main area of the system, including the motherboard, video system, drive, drive system, and keyboard. This ensures that all elements of the PC can be used safely. If a fault is detected, POST reports the faults as either an audible beeps (or beep code) are typically used to indicate faults that are detected prior to the video system initialization. By matching the beep code to your particular BIOS maker and version, you can usually determine the fault with great accuracy.
• Check the monitor. Make sure that the monitor is plugged in, turned on, set for proper brightness, and connected to the video adapter securely.
• Check the hardware conflicts. Video boards do not use interrupts or DMA channels, but they do use memory addresses. If the video board's memory addressed conflict with those of other devices in the system, the video board may not work.
• Check for exclusions. you may need to add an "exclude" switch to your memory manager's command line to preview other devices from using the memory spaces required by the video board.