Dell Latitude CP Reference And Troubleshooting Manual

Also see for Latitude CP: Service manual Service manual

Contents

4-20 Dell Latitude CP Reference and Troubleshooting Guidethe subtests in the Parallel Ports test group to check yourhardware. Although the following symptoms can becaused by faulty peripherals or software errors, theymight also suggest a port problem:• If a peripheral works intermittently or producesintermittent errors, the port may be faulty.• If the computer displays an error message that isrelated to the external device connected to a port, butcorrections to the device do not resolve the error, runthe appropriate subtest in the Parallel Ports testgroup.• If your software and the diagnostics do not recognizethat you have a parallel port, you should check theParallel Mode system setup option, and if necessary,run the appropriate subtest in the Parallel Ports testgroup.SubtestsThe four subtests in the Parallel Ports test group confirmthe following port functions:• Parallel Internal TestChecks several internal functions of the parallel port• Parallel External Loopback TestTests the functionality of the control lines through anexternal loopback connector, if an external loopbackconnector is available• Parallel External Interrupt TestTests the parallel port’s ability to generate interruptsfrom all possible sources, if an external loopbackconnector is available• Parallel Printer Pattern TestTests whether the port(s) can retain data, print texton a printer, and generate interruptsSCSI Devices Test GroupThe subtests in the SCSI Devices test group check thefunctionality of the small computer system interface(SCSI) controller in the C/Port APR or C/Dock Expan-sion Station, and the SCSI devices attached to either.These tests run only if the computer is docked.NOTES: Before conducting these subtests on an externalSCSI CD-ROM drive, insert into the drive a CD withaudio and data tracks (such as a multimedia CD). TheAudio Output Test requires a CD with audio tracks; allother subtests require a CD with data tracks.If the external CD-ROM drive is empty, or if it contains aCD that does not have the required data or audio tracks,the subtest fails.Why Run a SCSI Devices Test?If you check your SCSI hard-disk drive to determine theamount of available space, your operating system willprobably report problem areas. Problem areas on hard-disk drives are common, because most hard-disk driveshave a small amount of space that is not usable. Thehard-disk drive keeps a record of this space so that yourcomputer will not attempt to use it. Identification ofunusable disk space, unless it is an unusually largeamount (over five percent of the possible total), shouldnot be regarded as a cause for testing the hard-disk drive.These are the most common symptoms that might promptyou to test a SCSI device:• A SCSI hard-disk drive fails during the boot routine.• Seek errors are reported by the operating system orapplication programs.• An error message appears on the screen stating thatthe computer cannot read from or write to a SCSIdevice.• Data on a SCSI device is corrupted or lost; theseproblems may be intermittent. Once saved by a pro-gram, files cannot be properly recalled.SubtestsThe seven subtests in the SCSI Devices test group con-firm the following drive functions:• Internal Diagnostic TestCauses the device to run its internal self-test.• Seek TestChecks the device's ability to search for a specifiedtrack on the device and to position its read/writeheads to all tracks.