Running The Dell Diagnostics - Dell Dimension V400 Service Manual

This chapter describes diagnostic and beep codes and system error messages
that can occur during system start-up or, in the case of some failures, during
normal system operation. In some cases, the system may display error mes-
sages and emit beep codes simultaneously or may display a diagnostic code
and will not boot. In other cases, such as when a video problem occurs, the
system may emit a beep code even though it cannot display an error message.
If a faulty system does not emit diagnostic or beep codes or display system
error messages to indicate a failure, run the appropriate tests in the diskette-
based diagnostics to help you isolate the source of the problem. For instruc-
tions on starting and using the diskette-based diagnostics, see "Running the
Dell Diagnostics" in Chapter 2.
Your system is equipped with four diagnostic code indicators, which are
labeled "A," "B," "C," and "D" on the back of the computer. Each of the four
indicators can be yellow or green. When the computer is turned on or
restarted and the system is functioning normally, the indicators flash during
POST. After the system boots, the indicators remain green to signify normal
system operation.
If a malfunction is detected and the computer fails to boot, the indicators dis-
play a code that identifies the problem. In this situation, write down the
diagnostic code displayed and look it up in Table 3-1.
Diagnostic Codes, Beep Codes, and Error Messages 3-1