Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
01-29-2021, 02:16 PM   #1
New Member




Join Date: Jan 2021
Posts: 4
Takumar 55 f/1.8 (early version) A/M switch problems

Hey everyone,

I received my Takumar 55mm f/1.8 (early version with the red dot instead of red diamond) today and there is a problem - the lens is clean works nice but the Auto - Manual switch doesn't work. The lens is somehow always set on Auto (when I press the pin down the aperture stops down without any problem) no matter if I have it set on M or A its still open aperture.
Does anybody know what could cause the problem?
With Spotmatic its OK I can use it without any problems but when I want to switch to my Nikon DSLR there is a problem.


Thanks for any advice

01-29-2021, 10:05 PM   #2
Pentaxian
Just1MoreDave's Avatar

Join Date: Feb 2007
Location: Aurora, CO
Photos: Gallery | Albums
Posts: 5,851
The mechanism for the A/M switch is all within the mount, which is one solid aluminum piece. But it's probably repairable once you get to it, unless someone removed parts for unknown reasons. There are a couple of disassembly instructions for newer versions of the Takumar 55s here which have photos of the mechanism.

Pentax Lens Disassembly Database - PentaxForums.com

Pictures should give you an idea. Generally these lenses are the same with some exceptions. The 55/1.8s are basically the same as the 55/2s.

I am assuming your lens is labelled Auto-Takumar. All the screws on mine are slotted. For those lenses, you don't need a rubber grip to remove the front trim ring engraved with the lens name. The whole front barrel is threaded on. Just focus to 0.45m for more gripping room and unscrew that, it should come off easily. Then you can take off the focus ring by removing the three small screws just inside it. The DOF scale has tiny grub screws visible on the outside; just loosen these. Then you can slide off the aperture ring, being careful to retain the bearing trapped between the ring and lens body. It is probably under the orange dot. Then I think there are larger screws that were hidden by the aperture ring. Remove them and probably one or two long screws in slots whose heads fit into notches in the inside of the aperture ring. The lens mount piece can now come loose from the body and you can see the mechanism.

You don't need to unscrew the focus helix or any of the lens assemblies. You will need to make sure the focus ring goes back on so the lens can still focus to infinity. You can mark the ring when you remove it but I like to just adjust it afterwards. It's a good opportunity to clean the aperture ring and maybe regrease it. Use high-temperature grease and very little of it.
01-30-2021, 02:11 AM   #3
Loyal Site Supporter
Loyal Site Supporter




Join Date: Apr 2015
Posts: 1,454
Have a look at this picture, this could be the cause:
https://www.pentaxforums.com/forums/attachments/10-pentax-slr-lens-discussio...d-imgp3238.jpg
You find that there is a difference between the Aperture-pin and the Aut/Man-Release-pin which you need to push down to be able to switch.
Maybe that pin is somehow stuck.
If so, the Takumar is easy to open and repair.
01-30-2021, 02:45 AM   #4
New Member




Join Date: Jan 2021
Posts: 4
Original Poster
QuoteOriginally posted by photogem Quote
Have a look at this picture, this could be the cause:
https://www.pentaxforums.com/forums/attachments/10-pentax-slr-lens-discussio...d-imgp3238.jpg
You find that there is a difference between the Aperture-pin and the Aut/Man-Release-pin which you need to push down to be able to switch.
Maybe that pin is somehow stuck.
If so, the Takumar is easy to open and repair.
Thank you, but mine is older - its a Super Takumar (early 1962-1963) and it has only one pin. According to other sources - my lens should change the mode without pushing the pin.

Attached Images
 
01-30-2021, 02:49 AM   #5
New Member




Join Date: Jan 2021
Posts: 4
Original Poster
QuoteOriginally posted by Just1MoreDave Quote
The mechanism for the A/M switch is all within the mount, which is one solid aluminum piece. But it's probably repairable once you get to it, unless someone removed parts for unknown reasons. There are a couple of disassembly instructions for newer versions of the Takumar 55s here which have photos of the mechanism.

Pentax Lens Disassembly Database - PentaxForums.com

Pictures should give you an idea. Generally these lenses are the same with some exceptions. The 55/1.8s are basically the same as the 55/2s.

I am assuming your lens is labelled Auto-Takumar. All the screws on mine are slotted. For those lenses, you don't need a rubber grip to remove the front trim ring engraved with the lens name. The whole front barrel is threaded on. Just focus to 0.45m for more gripping room and unscrew that, it should come off easily. Then you can take off the focus ring by removing the three small screws just inside it. The DOF scale has tiny grub screws visible on the outside; just loosen these. Then you can slide off the aperture ring, being careful to retain the bearing trapped between the ring and lens body. It is probably under the orange dot. Then I think there are larger screws that were hidden by the aperture ring. Remove them and probably one or two long screws in slots whose heads fit into notches in the inside of the aperture ring. The lens mount piece can now come loose from the body and you can see the mechanism.

You don't need to unscrew the focus helix or any of the lens assemblies. You will need to make sure the focus ring goes back on so the lens can still focus to infinity. You can mark the ring when you remove it but I like to just adjust it afterwards. It's a good opportunity to clean the aperture ring and maybe regrease it. Use high-temperature grease and very little of it.
Thanks for the info - but mine is early model Super Takumar 345-2 which looks like the old Auto Takumars but its supposed to be the Super Takumar - so are the steps for disassembly the same as you mentioned or as the newer ones?
Attached Images
   
01-30-2021, 04:19 AM   #6
Loyal Site Supporter
Loyal Site Supporter




Join Date: Apr 2015
Posts: 1,454
Indeed, you are right, I have the early and the late version.
I forgot that the early version doesn't have that 2.nd pin.
And on mine the switch moves from M to Auto without any problem.

So I would disassemble it.
01-30-2021, 05:09 AM   #7
Pentaxian
D1N0's Avatar

Join Date: May 2012
Location: ---
Photos: Gallery
Posts: 6,367
Looks like there is some kind of tab under the a/m switch near the mount. Maybe that can be moved about?
01-30-2021, 07:09 AM   #8
New Member




Join Date: Jan 2021
Posts: 4
Original Poster
QuoteOriginally posted by D1N0 Quote
Looks like there is some kind of tab under the a/m switch near the mount. Maybe that can be moved about?
There is a small metal piece along the wall of the barrel and when I pull A/M switch to either position it moves - but I cant see it all through the gap from the rear mount side. I guess the only way is to disassembly and see what I can do.

01-30-2021, 10:27 AM   #9
Pentaxian
Just1MoreDave's Avatar

Join Date: Feb 2007
Location: Aurora, CO
Photos: Gallery | Albums
Posts: 5,851
QuoteOriginally posted by Johnny_Man Quote
Thanks for the info - but mine is early model Super Takumar 345-2 which looks like the old Auto Takumars but its supposed to be the Super Takumar - so are the steps for disassembly the same as you mentioned or as the newer ones?
Maybe? I have two of the Auto-Takumars, here's one:



It looks like your lens so there's a chance it is built the same. But there are small variations in my two lenses. It looks to me like they were hand-building everything at this time and not too concerned about interchangeable parts. I would try to unscrew the barrel. This is what it looks like on my lens:



If it doesn't seem that loose, don't force it. On my lenses, the trim ring with the engraved name does unscrew via the filter threads, like in the later Super-Takumars. But when I get it off, no screws are visible - later lenses have three screws visible that hold the barrel on. They also have three more screws holding the lens elements in, but as you see on my photo, early lenses have spanner slots to get those off.
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!
lens, pentax help, super takumar 55mm f1.8, takumar 55 f/1.8, troubleshooting
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
K3 vs A6500, to switch or not to switch redcat Pentax K-3 & K-3 II 110 06-10-2018 09:19 PM
M42 Super Takumar 135/3.5 version 1 vs. version 2 raymeedc Pentax SLR Lens Discussion 4 12-24-2009 11:49 AM



All times are GMT -7. The time now is 03:45 AM. | 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