Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
01-14-2017, 01:58 PM   #1
Forum Member




Join Date: Jan 2015
Posts: 58
K-S1 aperture block problem and possibly - a free and easy remedy

https://www.pentaxforums.com/forums/151-pentax-k-30-k-50/321871-k-30-k-50-ape...ml#post3881587


Please look at post No. 269, 272, 273

01-14-2017, 02:33 PM   #2
Otis Memorial Pentaxian
stevebrot's Avatar

Join Date: Mar 2007
Location: Vancouver (USA)
Photos: Gallery | Albums
Posts: 42,007
QuoteOriginally posted by marabella Quote
https://www.pentaxforums.com/forums/151-pentax-k-30-k-50/321871-k-30-k-50-ape...ml#post3879787

...and following posts.


FWIW, starting new threads to reference other threads is sort of frowned on. If you must have two threads, better to start a new, K-S1 specific, thread as you have done here and include all your good information in the initial post. Then comment on the old thread with a link to the new thread.


Steve
01-14-2017, 07:33 PM   #3
Forum Member




Join Date: Jan 2015
Posts: 58
Original Poster
Steve, I didn't consider this but I completely agree. My first thought was: Here we have another serious serial failure problem not only related to K30/K50 but also to the K-S1.
So here we go:


#269
And here is the first K-S1 with an aperture block failure.

Mine has started two days ago with black (heavily underexposured) pictures.
Battery in and out temporarily solved the issue but today the mechanism totally went stuck.

But I have made a very interesting discovery.
Carefully heating up the body (battery out) to 40°C on a radiator cured the problem - completely!
Unfortunately the black picture phenomenon returned as the camera cooled down to normal temperature (20°C).
Now I have to shoot two to five pictures before I get properly exposured photos.

May be this finding will help us finding the cause and hopefully a permant solution.


#272
AFAIK no one did report a faulty K-S1 in the forum's survey. But that's not the point.

Meanwhile I'm still testing. Results are promising but not satisfying so far.
The camera went from totally dead to a working state now after 1 to 3 black shots.

Perhaps somebody can repeat my procedure and post their result?

Heating up the camera to 40°C should be safe. User manual says 0 to 40. Battery and SD-Card removed. Carddoor open.
I place a thick book between the camera plus thermometer and the radiator.

I let the camera heaten up for 2 hours. Then gave it a burst shot (30-40).
I let it cool down for 2 hours and gave it a burst shot. Exposing it to different light will engage all aperture values. SD-Card not needed.

The second time I have put the camera upside down.

Now I'm continuing with both sides. Same procedure.

If this will fail I'm going to open the camera and try the repair procedure as it's described in this thread.


#273
Now, one day after, the camera is working as it should.
Correct exposure with both aperture and shutter speed from the beginning.

I do believe that heating up the camera's side where the solenoid is positioned did the trick.
I only can confirm this for my K-S1 and of course I don't know how other models will react to this method.

But I recommend this procedure before trying a self repair or sending it to a repair center.



Kind regards


Heribert


Who's interested in the whole story should read all posts in the K30/K50 sector.
01-14-2017, 11:01 PM   #4
Pentaxian
swanlefitte's Avatar

Join Date: May 2015
Location: Minneapolis
Photos: Gallery
Posts: 4,066
That sounds more like it was sticky blades on the lens. I could see heat freeing them up. Don't know enough from what i read.

01-15-2017, 05:13 PM   #5
Forum Member




Join Date: Jan 2015
Posts: 58
Original Poster
I appreciate your comment. But No! It is not sticky blades. It's a bad aperture block.
01-21-2017, 05:32 AM   #6
Veteran Member




Join Date: Nov 2013
Location: North Bohemia
Photos: Gallery
Posts: 1,251
QuoteOriginally posted by marabella Quote
I appreciate your comment. But No! It is not sticky blades. It's a bad aperture block.
I have done it on my K30 wich may have some dark frames and ussuale get to the lowest aperture when going LV..

I put it on a radiator with roughly 40 celsius without the battery and with bodycap facing the radiator..after around 2 hours it goes into LV with the correct aperture ( no bad sound..now it sounds normal..) I hope it will last.. THX!.. can't a some sort of glue or lubricant involved in this?
01-21-2017, 03:09 PM   #7
Forum Member




Join Date: Jan 2015
Posts: 58
Original Poster
An update dedicated to AldaCz and other affected K-S1 owners:

My solution did not last.

After about 50 shots my K-S1 went back to the "black picture status".

So I decided to go the russian way which is filing/sanding down the inner edges of the U-shaped metal piece inside the solenoid.
Why? Because this is reported as the repair procedure with the highest probability of success. I've read russian, french, german and english posts but there is no logical or plausible explanation. Only guesses and less or more successful workarounds. Additionally, I have soldered leads which a thicker profile.

All I can tell so far: After a long winter walk (-5°C to +20°C) my camera is still working. Beautiful snow pictures.

I will not publish any detailed steps of disassembling, repairing, assembling the K-S1 due to safety and responsibility reasons.
And I'm not willing to assist anyone via private message unless you proof your skills. Otherwise I strongly recommed to contact your repair center.

I'll keep you informed.

Here is a picture of my K-S1's innards before surgery:

Attached Images
 

Last edited by marabella; 01-21-2017 at 03:54 PM.
01-22-2017, 03:33 PM   #8
Forum Member




Join Date: Jan 2015
Posts: 58
Original Poster
QuoteOriginally posted by AldaCZ Quote
I have done it on my K30 wich may have some dark frames and ussuale get to the lowest aperture when going LV..

I put it on a radiator with roughly 40 celsius without the battery and with bodycap facing the radiator..after around 2 hours it goes into LV with the correct aperture ( no bad sound..now it sounds normal..) I hope it will last.. THX!.. can't a some sort of glue or lubricant involved in this?


This was my first thought when the dark pictures occure and heating up the camera (temporarily) did cure the failure.
But after examinating the entire mechanism I have to admit: I don't know but I doubt this.


It's the magnetic cohesion or a combination of cohesion and induction, I assume.
I've read the 230 pages/30MB French documentation that someone mentioned in the K30/K50 thread. This ingenious guy's conclusion was: Guesses.


You should speak Russian so I suggest to contact the Russian forum.
From what Google translate gave me they are very helpfully and politely.
01-23-2017, 01:17 PM   #9
Veteran Member




Join Date: Nov 2013
Location: North Bohemia
Photos: Gallery
Posts: 1,251
QuoteOriginally posted by marabella Quote
agnetic cohesion or a combination of cohesion and induction
oh, that has to be it. But it makes me wonder why not KR...but It has started after K30...
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
k-s1, k-s1 aperture block, k-s2
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
K-30 / K-50 Aperture Block Failue - Repair Solution available Altglas Pentax K-30 & K-50 1050 12-03-2023 12:25 AM
Survey with shutter count and aperture block or shutter failure. macman24054 Pentax K-30 & K-50 256 12-30-2016 11:47 PM
K-30 Aperture control and battery problem mgvh Troubleshooting and Beginner Help 10 10-21-2016 06:56 AM
Free and/or easy methods to remove shadows? MSL Digital Processing, Software, and Printing 12 12-31-2014 10:42 AM
K-7 and bellows : aperture problem fs999 Pentax DSLR Discussion 4 01-07-2010 02:03 PM



All times are GMT -7. The time now is 10:29 PM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top