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01-25-2011, 09:01 AM   #16
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wow, just imagine Pentax letting the customers do the dirty work for them. worth the $$$ ?

01-27-2011, 03:31 AM   #17
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RobA_Oz just confirmed that just turning the screw of the screw drive mechanism isn't sufficient.
01-29-2011, 03:04 PM   #18
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I can also confirm that twisting the focus screw does not help. I've used my lens on a K100D with its screwdrive af, and it was still dead using SDM on my K20D and K-7. Turning the SDM motor does something else obviously.
01-29-2011, 03:05 PM - 19 Likes   #19
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"By popular demand" I've now made a guide with lots of pictures for those daring to try this themselves. Its found here

01-29-2011, 04:43 PM   #20
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Very nice guide, thanks!
01-29-2011, 04:47 PM   #21
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Yes, well done. Thank you.
01-29-2011, 07:01 PM   #22
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Good job on that DIY guide. Should be a sticky.

01-30-2011, 09:35 AM   #23
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I suggest actually moving this article onto Pentax Forums, images and all. No matter what your take is on the issue, this procedure should be a resource here.

+1 rep for creating this!
01-30-2011, 10:04 AM   #24
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Very nice!

I'll be curious to know how long the lens works after this fix was applied. It sure beats a $300 repair.

Pat
01-30-2011, 12:10 PM   #25
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Svein, you say that you got a quote for repair abroad. Where was this? Did you check if the Norwegian repair center, Camera & Videoteknikk AS, could do the repair? Thanks for the guide, I'll remember it if/when my copy fails.
01-30-2011, 12:46 PM   #26
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I hope, I'll never need your instructions. But yes, that is very neatly done.
+1 (or 10 or whetever...)
01-30-2011, 01:21 PM   #27
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Svien,
Thank you very much for providing a professional quality guide!!! I may need it some day if either one of my 2 SDM's fail.

Let me ask a dumb question here: What's the difference between moving the motor via the screw or:
A. Moving the motor by electronically exercising the focus when it starts to have warm up problems? (I think there is no difference in this case, but it needs the motor to continue moving and not be totally stuck)

B. Moving the manual focus adjustment ring? (i suspect that quick focus clutch could slip and not actually unstick the motor)

Perhaps i've answered my own questions

best wishes,
01-31-2011, 06:26 AM   #28
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QuoteOriginally posted by EricT Quote
Svein, you say that you got a quote for repair abroad. Where was this? Did you check if the Norwegian repair center, Camera & Videoteknikk AS, could do the repair?
I got a quote from Fovi at the time the lens first failed (2009). This was at the time when Pentax was restructuring its distributor and service network. I was told SDM lenses had to be to Germany for repair, and the cost was estimated to 2500-3000 NOK (about 400-500 usd).

QuoteOriginally posted by philbaum Quote
Let me ask a dumb question here: What's the difference between moving the motor via the screw or:
A. Moving the motor by electronically exercising the focus when it starts to have warm up problems? (I think there is no difference in this case, but it needs the motor to continue moving and not be totally stuck)

B. Moving the manual focus adjustment ring? (i suspect that quick focus clutch could slip and not actually unstick the motor)
I think moving the screw head/back part of the motor does something different. It's not about moving the rotor/shaft. I think you're actually moving other parts of the motor.

If this indeed is some sort of utrasonic motor it is based on principles of friction with a piezoelectric material, my best guess regarding the fault os : 1. Maybe something sticks inside and need a nudge to get free or 2. perhaps its the other way around, that it gets too loose and the ultrasonic vibrations can't move the rotor. I'll have to read up on these kind of motors to know more.

Someone also asked if it could be that the mechanical autofocus link to the camera body also rotates when the SDM motor runs, and that the SDM motor doesn't have enough grunt to pull all that. It's an interesting thought. Maybe someone could try to remove the screwdrive af shaft from the lens? If the theory is correct you might even get slightly faster focusing because of less restistance/friction?
01-31-2011, 07:12 AM   #29
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QuoteOriginally posted by sveinmb Quote
"By popular demand" I've now made a guide with lots of pictures for those daring to try this themselves. Its found here
Very nicely Done!!!!
Thank you for making this seem easy. I think I might give this a try (if I can figure out how to work a screwdriver with my fingers crossed).
Has this repair method proven to have any longevity yet?
Brian
02-02-2011, 08:36 PM   #30
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Rep +1.

Awesome guide.
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