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01-04-2019, 06:25 PM   #796
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QuoteOriginally posted by madmax Quote
Hi, check youtube there is a guy that dissassambles the sdm drive motor. That may be helpfull. I watched it and It seemed to be too complicated to pay off for a longer usage after repair.
Please link to the video?
I watched many YT videos related to SDM but nobody disassembled SDM itself. They only turn by screw or replace whole unit. I already tried to disassemble it but I cannot turn screws out and get inside it holds sticked together

BTW I got message from KEH service that they are buying SDMs for much cheaper than offers I got but they cannot sell any parts itself to not break some agreement with Pentax.

01-04-2019, 06:52 PM   #797
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QuoteOriginally posted by RayeR Quote
Please link to the video?
I watched many YT videos related to SDM but nobody disassembled SDM itself. They only turn by screw or replace whole unit. I already tried to disassemble it but I cannot turn screws out and get inside it holds sticked together

BTW I got message from KEH service that they are buying SDMs for much cheaper than offers I got but they cannot sell any parts itself to not break some agreement with Pentax.
Maybe they would point you to their source?
01-05-2019, 01:28 AM   #798
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I quickly searched for:


"Pentax SDM repair"

it brings some Videos:

"https://www.youtube.com/watch?v=mr2pfj289a8"

That shows the SDM change procedure. Mybe it is usefull to contact the guy.


"https://www.youtube.com/watch?v=WgAbOIUgKLA"

This DIY. The Guy thinks that often not the Motor inself is broken, that iis Why he only trys to spin the Motor manually to break it lose. U might check and clean the contacts too.
I do not speak dutch but U see what he is doing.

And this Video:
"https://www.youtube.com/watch?v=SZiiG9MaZpY"

It shows how a guy gets the focus working again be tilting it a few times..

I hope that helps

Last edited by madmax; 01-05-2019 at 01:58 AM.
01-06-2019, 12:37 PM   #799
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>madmax
I already seen all this videos (and many more + many nighthours of googling a hints) but nobody there is DISASSEMBLYING THE SDM ITSELF as I had understand (maybe wrongly) from your previous post. I already disassembled my lens and pulled the SDM out but I'm unable to open it. There are 2 screws but sooo tight or the top screw turns around without an effect.
And yes, I contacted DIGI SERVICE from Bulgaria and they can send SDM for 135+15 euro.

KEH and other services probably get parts directly from pentax/ricoh and have some NDA signed to not resell the parts...
But I wonder there are no free SDMs recycled from some damaged lenses (e.g. after a fall on a rock with broken glass but as SDM source would be great).

01-06-2019, 02:06 PM - 1 Like   #800
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QuoteOriginally posted by RayeR Quote
I already disassembled my lens and pulled the SDM out but I'm unable to open it. There are 2 screws but sooo tight or the top screw turns around without an effect.
These two patents may help.

US7839053B2 - One-way rotational transfer mechanism, and ultrasonic rotary drive device incorporating one-way rotational transfer mechanism - Google Patents

US7531942B2 - Ultrasonic rotary drive device - Google Patents

Be aware that one of the screws might be a left hand thread (clockwise to loosen).

I have a slight suspicion that the problem might be in the One-way rotational transfer mechanism which prevents a screw drive from turning the SDM motor, I suspect it locks-up.
Notice the change in the patents between balls and rollers.
01-06-2019, 11:11 PM   #801
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>alfa75ts

Thaks,
It helped a bit to imagine what to expect inside. Today I disassembled it again and also tried to open SDM. There are 2 screws on the axle. One is glued and it seems doesn't screws out. Second is on gear bottom side. After some force where I need tightly and carefully hold the motor body it finally screwed out. The fell off some tiny plastic debris after I removed the gear from axle. I don't know how to disassemble further. See photos

http://rayer.g6.cz/hardware/pentax.k30/da1770b.jpg
http://rayer.g6.cz/hardware/pentax.k30/da1770e.jpg
http://rayer.g6.cz/hardware/pentax.k30/da1770f.jpg

And here is photo of the PCB
http://rayer.g6.cz/hardware/pentax.k30/da1770c.jpg

Please can somebody help to read the blown resistor value (pointed by arrow)? Those who still have this lens and know how to remove top cover.
http://rayer.g6.cz/hardware/pentax.k30/da1770d.jpg
01-13-2019, 02:21 PM   #802
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Just for interest here is total SDM disassembly (destructive, I had to grind off top screw that I couldn't screw out so I crewed it up
http://rayer.g6.cz/hardware/pentax.k30/da1770h.jpg
http://rayer.g6.cz/hardware/pentax.k30/da1770i.jpg
http://rayer.g6.cz/hardware/pentax.k30/da1770j.jpg
http://rayer.g6.cz/hardware/pentax.k30/da1770k.jpg
Now I know how to disassemble it probably without damage. Doesn't matter anyway, nikon motor is on the way so let's see if it will be usefull or just wasted 12$...
05-10-2019, 07:46 AM   #803
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Interesting reading this long long long trail of SDM failures and fixes. This has been a colossal catastrophe. Pentax apparently jumped in with both feet and put SDM in all their lenses without much, if any, Beta testing. It's a wonder they survived this.

05-11-2019, 11:42 AM - 1 Like   #804
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QuoteOriginally posted by silcam Quote
Interesting reading this long long long trail of SDM failures and fixes. This has been a colossal catastrophe. Pentax apparently jumped in with both feet and put SDM in all their lenses without much, if any, Beta testing. It's a wonder they survived this.
That sounds like the voice of someone who has recently suffered an SDM failure. Most who read this thread have gone through the same thing. Some of us might be angry or frustrated with our lenses, situation, or even Pentax. That's understandable, but a statement such as "it's a wonder they survived this" is a bit off.

I have had more issues with Nikon lenses and their focusing motors, even though my Pentax gear is used much more often. Yes, the SDM system is a very poor design. Yes, there is reason for your frustration, but at lesst we have options with Pentax. With so many lens choices and backward lens compatibility, choose other lenses (I love my FA* 80-200 and have no interest in the new 70-200, because my screw-driven 80-200 will last another 50 years without focus issues).
05-11-2019, 05:32 PM   #805
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QuoteOriginally posted by builttospill Quote
That sounds like the voice of someone who has recently suffered an SDM failure. Most who read this thread have gone through the same thing. Some of us might be angry or frustrated with our lenses, situation, or even Pentax. That's understandable, but a statement such as "it's a wonder they survived this" is a bit off.

I have had more issues with Nikon lenses and their focusing motors, even though my Pentax gear is used much more often. Yes, the SDM system is a very poor design. Yes, there is reason for your frustration, but at lesst we have options with Pentax. With so many lens choices and backward lens compatibility, choose other lenses (I love my FA* 80-200 and have no interest in the new 70-200, because my screw-driven 80-200 will last another 50 years without focus issues).
I switched from the new 70-200 and K-1 to a used DA*50-135/2.8 with working SDM - for two weeks. I didnít expect it to last. I simply converted it to screwdrive and moved on.

Last edited by monochrome; 05-12-2019 at 07:44 AM.
05-12-2019, 07:24 AM   #806
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QuoteOriginally posted by monochrome Quote
i switched from the new 70-200 and k-1 to a used da*135/2.8 with working sdm - for two weeks. I didnít expect it to last. I simply converted it to screwdrive and moved on.
50-135?
05-12-2019, 07:43 AM   #807
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QuoteOriginally posted by UncleVanya Quote
50-135?
Yes. Fixed above. In the mail.
05-12-2019, 01:42 PM - 1 Like   #808
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I noticed the info in this old thread included the DA* 60-250mm and thus infers that it can likewise be converted from SDM to screw-driven.

---------- Post added 05-12-19 at 01:47 PM ----------

QuoteOriginally posted by monochrome Quote
I switched from the new 70-200 and K-1 to a used DA*50-135/2.8 with working SDM - for two weeks. I didn’t expect it to last. I simply converted it to screwdrive and moved on.
Nothing wrong with that- it is a great lens and carries a lot better than a 70-200mm! And I suspect the screw-driven conversion provides faster AF. That said, so far I am among the fortunate, in having my DA* 50-135mm for some 10 years and the SDM still works very well. There have also been some lengthy periods of non-use! Even at least one period of 2 or 3 years!

Currently it is getting more use than ever with my KP, and mated with either my DA 20-40mm LTD or my Sigma 17-50mm f/2.8 EX DC.

Last edited by mikesbike; 05-12-2019 at 01:50 PM.
05-12-2019, 11:36 PM   #809
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QuoteOriginally posted by mikesbike Quote
I noticed the info in this old thread included the DA* 60-250mm and thus infers that it can likewise be converted from SDM to screw-driven.
It (60-250) can't (be converted to screwdrive) as far as anyone who uses this method can determine. 1 person in Russia reported a conversion, but their files do not work on other lenses. They had someone else repair it. The assumption is that some additional work was done internally.
05-14-2019, 06:46 AM   #810
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QuoteOriginally posted by mikesbike Quote
... so far I am among the fortunate, in having my DA* 50-135mm for some 10 years and the SDM still works very well. There have also been some lengthy periods of non-use! Even at least one period of 2 or 3 years!
Just to counterbalance your great luck, I had the SDM motor failure twice on my 50-135-- once under warranty and once not. The second time I converted it to screwdrive instead of paying for a fix I had no trust in.

Pentax never owned up to this technical part failure and I got a basic "screw you" feeling from them<pun!>. If not for this site these excellent lenses would have become either manual focus or paperweights.

Ricoh is not the same Pentax so hopefully they show better integrity and class towards their customers.
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