v Follow the suggested actions in the order in which they are listed in the Action column until the problemis solved.v See the parts listing in the Problem Determination and Service Guide to determine which components arecustomer replaceable units (CRU) and which components are field replaceable units (FRU).v If an action step is preceded by “(Trained service technician only),” that step must be performed only by atrained service technician.Symptom ActionThe monitor has screen jitter, orthe screen image is wavy,unreadable, rolling, or distorted.1. If the monitor self-tests show the that monitor is working correctly, consider thelocation of the monitor. Magnetic fields around other devices (such astransformers, appliances, fluorescent lights, and other monitors) can causescreen jitter or wavy, unreadable, rolling, or distorted screen images. If thishappens, turn off the monitor.Attention: Moving a color monitor while it is turned on might cause screendiscoloration.Move the device and the monitor at least 305 mm (12 in.) apart, and turn onthe monitor.Notes:a. To prevent diskette drive read/write errors, make sure that the distancebetween the monitor and any external diskette drive is at least 76 mm (3in.).b. Non-IBM monitor cables might cause unpredictable problems.2. Reseat the monitor cable.3. Replace the following components one at a time, in the order shown, restartingthe server each time:a. Monitor cableb. Monitorc. (Trained service technician only) System boardWrong characters appear on thescreen. 1. If the wrong language is displayed, update the BIOS code with the correctlanguage (see “Updating the firmware” in the Problem Determination andService Guide).2. Reseat the monitor cable.3. Replace the following components one at a time, in the order shown, restartingthe server each time:a. Monitorb. (Trained service technician only) System board64 System x3455 Types 7984 and 7986: Installation Guide