K850i the camera's lens cover doesn't open when I press button on. the screen is black and I can't take pictures. do you have idea what's wrong? tx

Is the lens cover opening ?

First try pressing the DISP or DISPLAY button on the back of your camera. If that doesn't help, try taking a picture with the screen black. Is the picture also black? If so, a stuck shutter is another common failure mode for digital cameras. The symptoms of a stuck or "sticky" shutter are very similar to CCD image sensor failure. The camera may take black pictures (for shutter stuck closed), or the pictures may be very bright and overexposed, sometimes with lines, especially when taken outdoors (for shutter stuck open). To confirm a stuck shutter, put the camera in any mode other than "Auto", and turn the flash OFF (you don't want to blind yourself for the next step). Next look down the lens and take a picture. You should see a tiny flicker in the center of the lens as the shutter opens and closes. If no movement is seen, then you likely have a stuck shutter. If so, please see this link for further info and a simple fix that may help.

Maybe the shutter got wet and sticky. You can try look into the lens then press shutter button to take picture. If you don’t see the movement inside the hole, the shutter doesn’t open, it will take black picture.

u know ur phone emi number and send it 2 my [email protected]

the camera trigger is damaged on the back of the main board needs to be replaced for software and hardware repairs contact kas at [email protected]

Hello, I went and researched a few points in the manual and hope this helps to some extent. If this doesn't help, try resetting your camera by removing the batteries for 30 seconds, then reinstalling them and turning on the camera again.
Monitor is blank:
• Camera is off.
• Batteries are not correctly inserted or battery-chamber
cover is not properly latched.
• Batteries are exhausted.
• EH-62B AC adapter (available separately) is not properly
connected.
• Camera is in sleep mode. Press shutter-release button
halfway.
• Monitor is off.
• USB cable is connected.
• AV/Video cable is connected


No picture is taken when shutter release button is pressed:


• Camera is in playback mode.
• Batteries are exhausted.
• Red (!) lamp flickers: flash is charging.
• Green (AF) lamp flickers: camera unable to focus.
• Message "CARD IS NOT FORMATTED" appears in
monitor: memory card is not formatted for use in your
camera.
• Message "OUT OF MEMORY" appears in monitor:
insufficient memory to record picture at current Image
mode setting.

Hello, I went and researched a few points in the manual and hope this helps to some extent. If this doesn't help, try resetting your camera by removing the batteries for 30 seconds, then reinstalling them and turning on the camera again. 
Monitor is blank: 
• Camera is off.
• Batteries are not correctly inserted or battery-chamber
cover is not properly latched.
• Batteries are exhausted.
• EH-62B AC adapter (available separately) is not properly
connected.
• Camera is in sleep mode. Press shutter-release button
halfway.
• Monitor is off.
• USB cable is connected.
• AV/Video cable is connected


No picture is taken when shutter release button is pressed:

• Camera is in playback mode.
• Batteries are exhausted.
• Red (!) lamp flickers: flash is charging.
• Green (AF) lamp flickers: camera unable to focus.
• Message "CARD IS NOT FORMATTED" appears in
monitor: memory card is not formatted for use in your
camera.
• Message "OUT OF MEMORY" appears in monitor:
insufficient memory to record picture at current Image Mode selection.

tuen on camera then press display a few times. it sounds like the display is just turned off. the lens system should be open.

just make sure your hands are not touching the side where the cam is... there is a sensor there that you might have been blocking while taking pics....

You could be suffering from a frozen Iris. This is the part of the lens which varies the amount of light entering the camera. Or the lens cover may not be opening when you switch on. Have you tried pushing the middle button of the 3 which run vertically on the rear of the camera below the mode switch. I had one on my bench a few weeks back which had an intermittent black screen. It started of as black and when I stripped it, cleaned all contacts and put it back together it the flashed on and off. I then stripped it again and went over every cable associated with the lens, CCD and video board checking them for breaks and recleaning them and bingo, everything came good. I have another 72 at the moment with a similar problem, I fixed the same way but got left with lines running across the picture. P72's aren't the best cameras picture wise and are close to the most troublesome, at least around here. For any of the above faults I'd recommend a visit to your local tech. Good luck. BMW