Kr autofocus problem

When pressing the AF it does the exact same the lens motor just seems to make the focus go in and out trying to focus but won't if you know what I mean.[/quote]Ah, I think we've all misunderstood and thought the AF didn't do anything. So it does, but doesn't select a focus point? Is that right?[/quote]Yes thats correct, sorry probably my fault as i'm hopeless when trying to explain things lol

As the focus isn't settling it sounds like an issue with the camera, however several possibilities to consider:
1. I'm sure you're not, but are you trying to focus on something like a plain wall that confuses the focussing?
2. Can you focus the lens manually?
3. Something else to check, has the viewfinder diopter setting slider moved making the viewfinder look out of focus?
4. When you take a photograph, even if it looks out of focus in the viewfinder, does it seem OK on the viewing screen? (Presuming it lets you.)
5. What happens in liveview?

1. I've tried focusing on several things not plain wall
2. yes I can focus manually
3. Just checked the diopter slider and in manual I made sure it was in focus
4. in AF it won't even let me take a photo it just tries to find the focus and won't let shutter click, where as on manual focus the shutter clicks every time.
5. not sure what you mean as i've never used live view, but in live view everything looks in focus but when I try to press shutter button it doesn't let me.

Hope i've explained properly!!!

Try cleaning the the electrical contacts on both the camera mount and lens. Bad electrical contacts would stop it focussing.

Whats the best way to do that as i've checked visually and both ends look clean.

Thanks again BTW for your patience in helping me

Use a soft cotton cloth to clean the contacts, best of all are the microfibre lens cloths.

Hopefully that's solved it, if not, when you focus manually, can you actually take a photograph? (Sorry, you've already answered that in the affirmative.)
Another probably silly unhelpful question, what lens('s) are you using? Its not unknown for the motors in some lenses to fail should the lens actually have a motor (thinking SDM here such as the 18-135mm.)
BUT - the lens is trying to focus so it doesn't sound like its a lens motor issue.
If its a normal 18-55 for instance the motor is in the camera body and it appears from what you've said that motor is working which could point to the AF module being iffy. I can't help with that one, other than to suggest that focusing in live view should work as it uses a different focusing system!

I've seen posts of a similar nature elsewhere, the solution being to clean the autofocus module lenses.

Hopefully someone with more knowledge than me can help, but I understand the AF module sits at the bottom of the mirror box, just inside the body.

Would be a bad idea to use a rocket blower pointed just below the mirror, towards the AF module?

I would have expected that Live View should work:
In Camera Menu 1 set AF Mode = AF.S.
In Camera Menu 3 select Live View and set Autofocus Method to the black and white circle (contrast detect).
In Spanner Menu 1 make sure that Beep is set to audible.
In C Menu 2 see that AF.S setting is 1.
Press the LV button for Live View.
Compose on the rear screen and half-press the shutter button - camera should focus the lens and beep its focus confirmation.
Complete the shutter press.
Does this work?

Cheers.
Philip

Check the AF/MF switch on the side of the lens mount fully one way then the tuther, also with lens off make sure that the screw for the auto focus making sure it extends retracts as necessary.

I am experiencing same problem, does anyone have any idea?

I've been using a 9 year old pentax k-r. Recently it stopped focusing with af.

When I press the focus button it does activate the motor and try to focus back and forth few times then it stops without focusing.

When I switch it to MF and focus manually, it does beep when object is in focus. So I think af sensor works well.

When I try to focus in liveview mode the visual zooms in but no effort on af motor and it shows red out of focus square.

Lenses does work with my z1-p well.

What causes this problem and can it be fixed?

History about the problem: one or two years ago I bought 50mm and 28mm manual lens with pentax super me and started film fotography and shooting with kr occasionally. Until then I was only using kit lenses 18-55 and 50-200. When I started using those manual lenses it began to cause a problem with my kit lenses. When I put my af lens to kr it started show it as manual focus. Then I tried to unmount and remount it fixed the problem sometimes, sometimes not. Recently I decided to clean contacts with alcohol. However I used 80° lemon cologne as alcohol. It fixed the problem that night, but a day later it stopped autofocusing as I mentioned above. Then I tried to clean contacts again with isopropanol but it didn't help.