Mirror will not return to rest position after photo is taken and shutter closes

The mirror motor on most KX, MZ, and other late model Pentax film cameras has a small plastic gear on the shaft that cracks, so that it will not drive the mirror up or down. Pentax originally replaced it with a larger gear made with better plastic, but they had problems with those also, so the eventually went with a brass gear

I don't believe the part is available any longer, or so I was told last time I tried to order one. Which is fine with me, as they are a real pain to work on and I do not recommend you try and fix it yourself.

Sorry

As the mirror moves up out of the way when a photo is taken this will have no effect on your pictures. The amount of dirt that you describe does seem to indicate that the camera is very dirty. You should clean it carefully, use no oil, anywhere, get all the dust and particles you can out of the camera. If there is dirt in the film transport area this will probably scratch the film as you wind on each time. The only dirt that will come out on the photos is any that is on the film when the photo is taken; these will be different each photo, or any on the back of the lens; these will be the same on each photo, but different for a different lens. Cleaning "the black part" from the lens side... this is actually the shutter itself, and is made from very thin metal. If you have bent or damaged this when cleaning it, you will have probably scrapped the camera. This can be changed, but only really by a repair shop. Again, dirt on this, either side, will not appear on photos, but might fall onto the film during exposure, leaving under exposed dust marks. Shutter blades can get tangled up, and not work nicely, not close properly. Try pressing the shutter with the back open and the lens off, looking through and see if there are any light leaks when the shutter is supposed to be closed.

Hi jandklandry, Sounds as though the cushion the mirror hits on the up swing is tacky thus holding the mirror up. Maybe you can yourself fix it however, I would suggest sending it to Nikon for a complete CLA (Clean Lube Adjust). You have a nice camera allow Nikon to do it proud.

it sounds like its set up for a very slow shutter speed
ie:30sec's? and your getting triger happy trying to rush it to take the photo and get it over with, check when film speed its set on and what shutter speed its set to,and stop poking the mirror about or its going to cost you big time bucks getting it fixed,

Sounds like the shutter or mirror assemble is damaged and needs repair. This is a major repair that a technician will need to preform.

The reason the mirror is acting up is because the Shutter is going bad under slow shutter speeds. > The motor which drives the shutter charge and the mirror up and down is the same .

The shutter & mirror is in need of a CLA. Clean, Lube & Ajustment. Its well needed for any camera when they are 20 years old and older

By "stayed up", do you mean that the mirror remained in the up position so that you could not see anything in the viewfinder or do you mean that the shutter actually remained open? I do not remember the exact features on your camera, but in general, this is what I would do.

1) Remove the film from the camera and take a picture. Note if you see anything in the viewfinder. If you see nothing, the mirror is in the up position. Verify this by removing the lens and opening the door on the camera back. Look through the lens hole. If you can see through the rectangular hole at the film plane, the shutter is open. If instead you something is obstructing the hole, the shutter is closed. In any case DO NOT TOUCH THE SHUTTER! The shutter is what is covering the hole.

2) If the mirror is in the up position, check to see if your camera has a feature that allows locking the mirror in the up position. Some cameras have this feature to allow use of lenses with very short focal lengths. If this is the case, simply unlock the mirror.

3) If the shutter is the problem, your shutter speed may be set to "T", which stands for time. In the time exposure mode, you press the shutter release once to open the shutter and a second time to close the shutter. Cameras with a "T" setting also have a "B" setting, which stands for bulb. This is a throwback to the old days when it was common to use air-powered shutter releases rather then cable releases. The bulb was a rubber bulb that you squeezed to force air through a tube and push a pin to activate the shutter. The "B" setting keeps the shutter open as long as you hold the shutter release in, but as soon as you take your finger off the shutter release, the shutter closes. Both of these settings are used to make timed exposures. If you find that the problem was that the shutter was set to "T", set the shutter speed to 1/25th second or so and try again. The following sequence should occur; the mirror will flip up and the viewfinder image will disappear, the shutter will open for the prescribed time and close, the mirror will return to the down position and you will again see through the viewfinder.

If this does not work, you may need to take it in for repair.

The camera firmware should be reloaded, if this fails then the camera is likely beyond end user servicing and should be repaired by a professional.

The reason your only seeing bottom half is as the reflex mirror is opening upwards to expose the sensor ( traditional cameras opened the mirror then a shutter to expose film ) your cameras sensor is only registering or transferring the bottom half of the image because it is the image is registered bottom first to the top until the shutter closes and the mirror returns to resting position.

Your problem could be the result of firmware or a more serious issue.