just repaired a-50mm 1.7

bavd · 01-30-2015, 08:49 AM - **1 Like**

A co worker gave me 2 pentax lenses a 50mm A 1.7 and a 135mm M 3.5, both looking mint.
Sadly the 50mm was suffering from the "stuck aperture syndrome" and since it was a freebee i decided to try and repair the lens.
Folowing the repair instructions by forum member just1moredave ( https://www.pentaxforums.com/forums/114-maintenance-repair-articles/88051-pen...ng-repair.html ) I was able to repair the lens! Put it on my k3 and now it works fine. Im so happy!
If you have a good 50mm 1.7 with a stuck aperture ring give it a try, its worth it. Nice lens. Be sure to take your time and be patient it is a VERY fiddely operation.
Do use the plastic bag tip and don't loose any of the small parts. Took me 10min to take apart and 2hrs to fix and put back together.

bavd · 01-30-2015, 09:18 AM

Originally posted by dcshooter

Congratulations on your first repair! The little electronic contact on the a lense scan be maddening to reinstall.

Yes it was. Strangely, mine looked diffrent from the one in the repair manual? So probably they did a design change somewhere along the line.
But i am glad I did it. Now just waiting for daylight and some better weather to make some use of it.

**patrick9** · 01-30-2015, 06:43 PM

Congratulations . so far the only lenses I have repaired is an AI Nikkor 55mm. It had internal fungus and stuck focus ring.

Not a Number · 01-30-2015, 07:01 PM

Only two hours? It probably took me 3 or 4 times that over several days. The little "A" pin assembly on mine would fall apart just looking at it and takes a lot of fiddling to get it back together. Having over 50 year old eyesight doesn't help.

Too bad you didn't take any photos, I'd be interested to see what the differences are.

bavd · 01-31-2015, 02:49 AM

Originally posted by Not a Number

Only two hours? It probably took me 3 or 4 times that over several days. The little "A" pin assembly on mine would fall apart just looking at it and takes a lot of fiddling to get it back together. Having over 50 year old eyesight doesn't help.

Too bad you didn't take any photos, I'd be interested to see what the differences are.

I have to say you do need 2 pair of hands putting it back together! And my eyes are over 50 aswell. What helped was sticking the little parts together with some grease so they don't fall off all the time.
The biggest problem in my opinion is preventing any of those parts to fall into the lens....
I should have taken some photos but only thought of it afterwards. The main diffrence between my lens and the example given by just1moredave was in the electrical contact, the little silver "bullit".
In my lens the holder had a round topplate instead of a square one. (made it even smaler!)
Still i am glad i did it and it worked.

Not a Number · 01-31-2015, 06:21 AM

Originally posted by bavd

What helped was sticking the little parts together with some grease so they don't fall off all the time.

The problem with that is if it is non-conductive grease the "A" pin will stop working. I had to take the pin assembly out and clean off all the grease a couple times to get it working reliably.

01-30-2015, 08:49 AM - 1 Like	#1
bavd Forum Member Join Date: Jan 2015 Location: Almere (NL) Posts: 96	just repaired a-50mm 1.7 A co worker gave me 2 pentax lenses a 50mm A 1.7 and a 135mm M 3.5, both looking mint. Sadly the 50mm was suffering from the "stuck aperture syndrome" and since it was a freebee i decided to try and repair the lens. Folowing the repair instructions by forum member just1moredave ( https://www.pentaxforums.com/forums/114-maintenance-repair-articles/88051-pen...ng-repair.html ) I was able to repair the lens! Put it on my k3 and now it works fine. Im so happy! If you have a good 50mm 1.7 with a stuck aperture ring give it a try, its worth it. Nice lens. Be sure to take your time and be patient it is a VERY fiddely operation. Do use the plastic bag tip and don't loose any of the small parts. Took me 10min to take apart and 2hrs to fix and put back together.

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01-30-2015, 09:18 AM	#2
bavd Forum Member Join Date: Jan 2015 Location: Almere (NL) Posts: 96 Original Poster	Originally posted by dcshooter Congratulations on your first repair! The little electronic contact on the a lense scan be maddening to reinstall. Yes it was. Strangely, mine looked diffrent from the one in the repair manual? So probably they did a design change somewhere along the line. But i am glad I did it. Now just waiting for daylight and some better weather to make some use of it.

01-30-2015, 06:43 PM	#3
patrick9 Site Supporter Join Date: Feb 2011 Location: Murfreesboro Tennessee Photos: Gallery \| Albums Posts: 3,458	Congratulations . so far the only lenses I have repaired is an AI Nikkor 55mm. It had internal fungus and stuck focus ring.

01-30-2015, 07:01 PM	#4
Not a Number Moderator Join Date: Mar 2012 Location: Venice, CA Posts: 10,526	Only two hours? It probably took me 3 or 4 times that over several days. The little "A" pin assembly on mine would fall apart just looking at it and takes a lot of fiddling to get it back together. Having over 50 year old eyesight doesn't help. Too bad you didn't take any photos, I'd be interested to see what the differences are.

01-31-2015, 02:49 AM	#5
bavd Forum Member Join Date: Jan 2015 Location: Almere (NL) Posts: 96 Original Poster	Originally posted by Not a Number Only two hours? It probably took me 3 or 4 times that over several days. The little "A" pin assembly on mine would fall apart just looking at it and takes a lot of fiddling to get it back together. Having over 50 year old eyesight doesn't help. Too bad you didn't take any photos, I'd be interested to see what the differences are. I have to say you do need 2 pair of hands putting it back together! And my eyes are over 50 aswell. What helped was sticking the little parts together with some grease so they don't fall off all the time. The biggest problem in my opinion is preventing any of those parts to fall into the lens.... I should have taken some photos but only thought of it afterwards. The main diffrence between my lens and the example given by just1moredave was in the electrical contact, the little silver "bullit". In my lens the holder had a round topplate instead of a square one. (made it even smaler!) Still i am glad i did it and it worked.

01-31-2015, 06:21 AM	#6
Not a Number Moderator Join Date: Mar 2012 Location: Venice, CA Posts: 10,526	Originally posted by bavd What helped was sticking the little parts together with some grease so they don't fall off all the time. The problem with that is if it is non-conductive grease the "A" pin will stop working. I had to take the pin assembly out and clean off all the grease a couple times to get it working reliably.