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Aford
Tinkerer
Username: Aford
Post Number: 70
Registered: 03-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, January 06, 2010 - 03:42 pm: | 
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Asahiflex IIa (an early Pentax SLR 1953)
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When I rotate the film wind-on knob (clockwise) the knob is being pulled backwards (counter clockwise) by the shutter curtain springs until that is, the shutter is cocked.
When I first got the camera the knob was quite stiff to turn and the wind-on seemed normal. Only after giving the camera a CLA that made the wind-on much easier did this problem arise.
I've had the top and bottom covers off but can find no mechanism to prevent the wind-on knob moving backwards as the knob is rotated.
Is this normal? or is there a one-way spring (anti-reverse spring) missing? Or perhaps there is a ratchet pawl and spring that is not working, but I can't see it!
When I first attempted to removed the top cover for the CLA, the wind knob was very hard to unscrew, although I did not try too much force somebody may have done so in the past and damaged the anti-reverse mechanism. I managed to unscrewed the knob quite easily after heating it up with a hair dryer. I'm reluctant to put a film though the Asahiflex until this is resolved.
Would wecome any advise. Thanks - Alf |
Chiccolini
Tinkerer
Username: Chiccolini
Post Number: 73
Registered: 06-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, January 06, 2010 - 05:53 pm: |
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Is that a problem?
I have a Voigtlander Vito B and had a few Kodak 35 RFs that did this. Also a few others I don't remember (none Asahi). |
Aford
Tinkerer
Username: Aford
Post Number: 71
Registered: 03-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, January 07, 2010 - 12:18 pm: |
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Chiccolini
I agree that its not realy a problem, more of an annoyance for me as I've spent a lot of time restoring this camera only to find this happening. As it is the camera should take pictures ok.
It takes three turns of the knob to cock the shutter and each time the grip on the knob is releasd it slips backwards slightly, I've never come across it before and to me it seems wrong.
What I would like to know is, does the Asahiflex IIa normally have a anti-reverse spring fitted to the wind knob or are these parts missing?
Can somebody help please. Thanks - Alf |
Glenn
Tinkerer
Username: Glenn
Post Number: 737
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, January 07, 2010 - 05:12 pm: |
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From distant memory there is no 'reverse' mechanism on the wind shaft. In carrying out the CLA you have either got too much lube on the shaft, or more likely not torqued up the knob sufficiently to provide grip. Unfortunately in old mechanisms dirt and debris often compensate for wear and removing same leads to all kinds of problems, you may need a thin shim washer under the knob to restore the original factory set resistance. |
Aford
Tinkerer
Username: Aford
Post Number: 72
Registered: 03-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, January 08, 2010 - 04:31 pm: |
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Glenn
I had a closer look underneath the wind knob but I find there is no means of applying friction as you have suggested.
There is a shim and a wavy washer under the knob but they are there to provide friction for the frame counter dial.
I forgot to add in my original post that the Asahiflex IIa was sold in the USA as the TOWER 22. Anybody got one of these?
It was sold by Sears & Roebuck many years ago for $129.50.
Thanks - Alf |
Krg
Tinkerer
Username: Krg
Post Number: 6
Registered: 10-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 10, 2010 - 01:24 am: |
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This is not normal. I do not have this problem with my Asahiflex, although I hear no ratchet, perhaps the curtain springs too tight. |
Vinzenz
Tinkerer
Username: Vinzenz
Post Number: 29
Registered: 06-2008
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 10, 2010 - 03:40 am: |
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Hi Alf
The Asahiflex II which I repaired some time ago belonged to someone else. Therefore, I cannot verify if the winding knob has a catch to prevent it from slipping back. As I remember it did not slip back.
I have a few images from the repair which might be of use for you. Check the gears and moving parts on the left of the winding knob (seen from the back of the camera), especially the function of the rod (red circle in the last picture). It is linked to a lever in the mirror box.
I had to guess a bit while reassembling the camera to make it work proberly. I could send you more images if needed. I hope this helps.
Good luck
Vinzenz
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Aford
Tinkerer
Username: Aford
Post Number: 73
Registered: 03-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 10, 2010 - 01:22 pm: |
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Vinzenz,
Thanks for that information and the great pictures, I will certainly look again at the part you have circled. I was too scared to poke around in that area previously because of the springs there, they are the about the thickness of a spiders web!!
I found the pictures very helpful and would certainly appreciate a clearer picture of the wind-on shaft (without the knob) as shown in the second picture, if you have one.
Thanks for your help - Alf |
