Nokia RM-42 Service Manual

Also see for RM-42: Service manual

Contents

Figure 93 Bit errors caused by JPEG compressionOne type of bit error is a lack of bit depth. In this case, the image is almost totally black under normal conditions,and only senses something in very highly illuminated environments. Typically this is a contact problem betweenthe camera module and the phone main PWB. You should check the camera assembly and connector contacts.If the fault is in the camera module, bit errors are typically visible only when using some specific imageresolution. For example, in case of a viewfinder fault, the error might exist but is not visible in a full size image.Faulty pixels in imagesFaulty pixels are pixels that do not respond to light in the same way as the pixels around them. There are threemain types of faulty pixels, dead, stuck and hot pixels.Dead pixels are always black or significantly darker than their surrounding. Dead pixels appear as black spotsin all lightning conditions. Camera modules producing images with dead pixels that are clearly noticeable shouldbe replaced.If the pixel remains always saturated to its maximum value it is stuck. Stuck pixels may appear as red, green,blue or white spots in all lightning conditions. Camera modules producing images with one or more stuck pixelsshould be replaced.Hot pixels are pixels that easily saturate in dim light conditions. It is normal to get a lot of noise and hot pixelsin night conditions or otherwise dark conditions. The hot pixels should disappear when the ambient light isincreased, but may still appear in darker areas of an otherwise well illuminated scene.When examining an image for defect pixels test images should be viewed as 100% enlargements on a PCmonitor.RM-42Nokia Customer Care Camera Module TroubleshootingPage 8–16 Company Confidential 9241872 (Issue 1)Copyright ©2005 Nokia. All Rights Reserved.