Dell Latitude CP Reference And Troubleshooting Manual

Also see for Latitude CP: Service manual Service manual

Contents

4-14 Dell Latitude CP Reference and Troubleshooting Guideproblem and cannot isolate the failure or malfunction to aparticular system board component.The System Set test group also verifies the proper opera-tion of other computer components, such as the speaker,that are not tested elsewhere in the diagnostics.The following symptoms usually suggest a problem witha component or subassembly that warrants running a Sys-tem Set subtest:• A program is not running as usual, or a proven pieceof software appears to malfunction and you confirmthat the software itself is not at fault. (You can con-firm that the software is functioning properly bymoving it to another computer and running it there.)• A PC Card you previously accessed can no longer beaccessed.• The computer periodically locks up, especially atdifferent places and times in different programs.• Parity errors or page fault failures (any error mes-sage that contains the word parity or page fault) occurat any time during operation. These errors are usuallyaccompanied by a reference to an address, which youshould record on a copy of the Diagnostics Checklistfound in Chapter 5.• Correcting errors in the system configuration infor-mation does not resolve a problem.• The computer’s clock/calendar stops.• The speaker no longer functions. The problem couldbe a failure of the system timers as well as a failureof the speaker itself. Run the System Timers Test,followed by the System Speaker Test.• If a peripheral device appears to malfunction, run theInterrupt Controllers Test. If the computer fails thetest, the problem lies with the interrupt controller; ifthe computer passes, then the problem lies with theperipheral device.• A spreadsheet program or other type of mathemati-cal application runs abnormally slow, generates errormessages concerning calculations or operations, runsincorrectly, or generates incorrect results; or aproven piece of the program appears to malfunctionand you confirm that the software itself is not atfault. (You can confirm that the software is not atfault by moving the program to another computerand running it there.)• The computer halts in the middle of performing cal-culations or complex mathematical operations.SubtestsThe 11 subtests in the System Set test group confirm the fol-lowing computer functions:• CMOS Confidence TestChecks the nonvolatile RAM (NVRAM) for accessi-bility and reliability of data storage by performing adata pattern check and verifying the uniqueness ofmemory addresses.• DMA Controller TestTests the direct memory access (DMA) controllerand verifies the correct operation of its page andchannel registers by writing patterns to the registers.• Real-Time Clock TestConfirms the functionality and accuracy of the com-puter’s real-time clock (RTC).• System Speaker TestChecks the functionality of the speaker by generat-ing eight tones.• System Timers TestChecks the timers used by the microprocessor forevent counting, frequency generation, and otherfunctions. Only the functions that can be activatedby software are tested.• Interrupt Controller TestGenerates an interrupt on each interrupt request(IRQ) line to verify that devices using that line cancommunicate with the microprocessor and that theinterrupt controller sends the correct memoryaddresses to the microprocessor.• Coprocessor Calculation TestChecks the use of different types of numbers and themath coprocessor’s ability to calculate correctly.• Coprocessor Error Exception TestVerifies the math coprocessor’s ability to handleerrors and to send IRQs to the microprocessor.