SMC pentax-a 1:2 50mm
Posted 06/02/2013 - 05:54
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That's the A-pin (one of the contacts on the PK/A mount).
From memory, there is a notch that it sits in underneath the metal mount. To reassemble it, you need to set the aperture ring to the 'A' position, balance the pin in the notch where it sits and carefully re-fit the mount.
Hope this helps.
From memory, there is a notch that it sits in underneath the metal mount. To reassemble it, you need to set the aperture ring to the 'A' position, balance the pin in the notch where it sits and carefully re-fit the mount.
Hope this helps.
Posted 06/02/2013 - 15:44
Link
As per the previous post this assembly forms the ccontact pin. Handle with care as it is actually three separate components.
For refitment
1. Set the Aperture ring to the 'A' position.
Look down at the lens mount and note the position of the 'hole' were the pin pops through relative to the body of the lens.
2. Place the lens front down/mount up and carefully remove the five screws that hold the mount to the body. Do not hold the lens by the aperture ring as it can easily become dislodged and the small indent ball bearing may be lost.
3. Before going any further note how the assembly resembling O-X26 on the drawing is fitted. It too can sometimes become dislodged.
4. Now recalling the position of the 'hole' in the mount, look down at the lens and you will see a slight recess on the outside of the lens body. The slot formed by the recess and the aperture ring is where the pin assembly is located.
5. Carefully drop the assembly in place and apply a small amount of pressure to compress the spring. Holding the compressed assemply in position carefully move the aperture ring away from the 'A' postion, F16 is fine.
6. You can then let go of the assembly which will now be held compressed and in position, by another slot on the aperture ring.
7. Before refitting the lens mount check that the O-X26 assembly is still in position.
8. Once refitted check that the aperture blades are moving freely through their range. If they are not moving correctly the O-X26 assembly is not correctly located.
9. Then put the lens into 'A' mode and the contact pin will be released from its retaining slot and you should see it move slightly.
Thats about all there is to it. Relatively easy, provided you exercise a little care when disassembling and handling the contact pin.
Regards - Steve
For refitment
1. Set the Aperture ring to the 'A' position.
Look down at the lens mount and note the position of the 'hole' were the pin pops through relative to the body of the lens.
2. Place the lens front down/mount up and carefully remove the five screws that hold the mount to the body. Do not hold the lens by the aperture ring as it can easily become dislodged and the small indent ball bearing may be lost.
3. Before going any further note how the assembly resembling O-X26 on the drawing is fitted. It too can sometimes become dislodged.
4. Now recalling the position of the 'hole' in the mount, look down at the lens and you will see a slight recess on the outside of the lens body. The slot formed by the recess and the aperture ring is where the pin assembly is located.
5. Carefully drop the assembly in place and apply a small amount of pressure to compress the spring. Holding the compressed assemply in position carefully move the aperture ring away from the 'A' postion, F16 is fine.
6. You can then let go of the assembly which will now be held compressed and in position, by another slot on the aperture ring.
7. Before refitting the lens mount check that the O-X26 assembly is still in position.
8. Once refitted check that the aperture blades are moving freely through their range. If they are not moving correctly the O-X26 assembly is not correctly located.
9. Then put the lens into 'A' mode and the contact pin will be released from its retaining slot and you should see it move slightly.
Thats about all there is to it. Relatively easy, provided you exercise a little care when disassembling and handling the contact pin.
Regards - Steve
Posted 06/02/2013 - 22:24
Link
Thanks guys for the reply...I really dont follow what you mean by A position. I did find this link though:
http://grantharg.tripod.com/CameraRepair/M50mmfixa.htm
except his images dont seem to show this piece (but is mentioned i think in step 4).
Here is another image of what Im thinking.
My thought is with the ball bearing where it is, it lines up with a hole on the metal ring which screws down...without something blocking this hole the bearing falls out.
Question is, if this is correct, does the spring sit on the ball bearing or just near it?
http://grantharg.tripod.com/CameraRepair/M50mmfixa.htm
except his images dont seem to show this piece (but is mentioned i think in step 4).
Here is another image of what Im thinking.
My thought is with the ball bearing where it is, it lines up with a hole on the metal ring which screws down...without something blocking this hole the bearing falls out.
Question is, if this is correct, does the spring sit on the ball bearing or just near it?
Posted 06/02/2013 - 23:41
Link
https://www.pentaxforums.com/forums/maintenance-repair-articles/88051-pentax-50m...
should be my answer!
thanks everyone hopefully it works...
should be my answer!
thanks everyone hopefully it works...
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3 posts
13 years
I was working on fixing an old 50mm I found laying around and when taking it apart this part fell out...
I found this link:
http://i184.photobucket.com/albums/x261/ClarkyinAus/50mmlensillustration.jpg
and think that it is part X33? I can't for the life of me figure out how to re-assemble with this part! Any help is greatly appreciated.
Thanks!
James