LCD-related symptomsImportantThe TFT LCD for the notebook computer containsmany thin-film transistors (TFTs). The presence of asmall number of dots that are missing, discolored, oralways lighted is characteristic of TFT LCDtechnology, but excessive pixel problems can causeviewing concerns. The LCD should be replaced ifthe number of missing, discolored, or lighted dots inany background is:v XGA: 8 or more bright dots, 8 or more dark dots,or a total of 9 or more bright and dark dots.v SXGA+: 11 or more bright dots, 13 or more darkdots, or a total of 16 or more bright and darkdots.v UXGA: 11 or more bright dots, 16 or more darkdots, or a total of 16 or more bright and darkdots.v QXGA: 15 or more bright dots, 16 or more darkdots, or a total of 16 or more bright and darkdots.Note: A bright dot means a pixel is always on(white or color.) A dark dot means a pixel isalways off (black color.)Symptom or error FRU or action, in sequenceNo beep, power-on indicatoron, and a blank LCD duringPOST.System board.v LCD backlight not working.v LCD too dark.v LCD brightness cannot beadjusted.v LCD contrast cannot beadjusted.1. Reseat the LCDconnectors.2. LCD assembly.3. System board.v LCD screen unreadable.v Characters missing pixels.v Screen abnormal.v Wrong color displayed.1. See important note for“LCD-related symptoms.”2. Reseat all LCD connectors.3. LCD assembly.4. System board.Horizontal or vertical linesdisplayed on LCD.LCD assembly.Symptom-to-FRU indexThinkPad R50/R50p and R51 Series 61
