Service manual

Running the Dell Diagnostics: Dell Latitude CP
● Data pattern checks, to look for RAM bits that are stuck high or low, short-circuited data
lines, and some data pattern problems that are internal to the memory chips
● A parity check that verifies the ability of the memory subsystem to detect errors
● A refresh check, to verify that the dynamic RAM (DRAM) is being recharged properly
System Set Test Group
The subtests in the System Set test group check the computer's basic system board
components and verify their related functions.
Why Run a System Set Test?
The System Set subtests double-check many system board components, such as the
computer's I/O circuitry, that are tested by other test groups or subtests in the diagnostics. You
should run the System Set test group if you are having a problem and cannot isolate the failure
or malfunction to a particular system board component.
The System Set test group also verifies the proper operation of other computer components,
such as the speaker, that are not tested elsewhere in the diagnostics.
The following symptoms usually suggest a problem with a component or subassembly that
warrants running a System Set subtest:
● A program is not running as usual, or a proven piece of software appears to malfunction
and you confirm that the software itself is not at fault. (You can confirm that the software
is functioning properly by moving it to another computer and running it there.)
● A PC Card you previously accessed can no longer be accessed.
● The computer periodically locks up, especially at different places and times in different
programs.
● Parity errors or page fault failures (any error message that contains the word parity or
page fault) occur at any time during operation. These errors are usually accompanied by
a reference to an address, which you should record on a copy of the Diagnostics
Checklist found.
● Correcting errors in the system configuration information does not resolve a problem.
● The computer's clock/calendar stops.
● The speaker no longer functions. The problem could be a failure of the system timers as
well as a failure of the speaker itself. Run the System Timers Test, followed by the
System Speaker Test.
● If a peripheral device appears to malfunction, run the Interrupt Controllers Test. If the
computer fails the test, the problem lies with the interrupt controller; if the computer
file:///I|/SERVICE%20MANUALS/DELL%20MANU...ES%20REF%20AND%20TROUBLESHOOTING/RUN.HTM (19 of 37)6/21/2004 1:38:45 AM