Hi.... I've just bought an iphone from ebay that apparently was working perfectly. Since I've received it the screen has been very dim - it's really hard to see any of the icons except in bright light. I've gone into settings to change the brightness - nothing happens. I've restored settings and resynced to itunes with latest software. Still the same. Does anyone have any ideas how to fix this? I don't currently have a SIM in it - would that be causing the problem? Thanks!