Found a cheap and effective way to fix SDM failures.

dynaudio · 03-27-2016, 03:43 PM

Hi,

Please look at my post (#7) in this thread:

https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/309581-da-1...fix-check.html

I can confirm working method with a small screwdriver, someone mentioned earlier. If anything I would strongly advise not to use AF to force SDM motor to move stuck parts inside the lens. Trying to so may actually overstrain the SDM motor and kill it.

slip · 03-29-2016, 11:08 AM

Originally posted by GeneV

If the theory is that it is just the clutch, then it should not work on the 17-70, with no quick shift clutch or screw drive. Mine only has issues above 55mm, so that is likely to be a different issue altogether. Some others have had the SDM fail entirely.

the copy I am selling has the same issue.
sdm seems fine, though

LeDave · 10-27-2016, 09:33 AM

Okay, I thought I'd want to post this. After a few years of having to warming up my 16-50 to auto focus, it is no longer there. About 2 months now, I can leave the lens in my bag for a long time, and put it back on and it'll auto focus right away without having to do the warm-up tactics. The SDM works perfectly fine now. It is very strange.

Hmong_Xiong · 11-11-2016, 10:37 AM

Originally posted by LeDave

Okay, I thought I'd want to post this. After a few years of having to warming up my 16-50 to auto focus, it is no longer there. About 2 months now, I can leave the lens in my bag for a long time, and put it back on and it'll auto focus right away without having to do the warm-up tactics. The SDM works perfectly fine now. It is very strange.

My 16-50 does the same. It makes me want to get a new one since it's my most used lens but yet I don't want to get a new one because it still works great...when it wants to work.

dynaudio · 11-12-2016, 03:35 AM

Hi, as I sad in my thread. Most likely the reason behind weird af behaviour is thickening grease. Possibly in clutch. Turning af screw with a small screwdriver back and forward few times usually solves the problem.

**chuck_c** · 11-18-2016, 10:33 AM

Originally posted by LeDave

3/5/2016 Update:

Hey guys, I found another cheap way to quick fix the SDM problem. You just hold the AF button down for a couple of seconds and let go, then you hold the AF button down for a couple of seconds and let go, repeat, repeat, and repeat until it starts to move and focus again.

Just three days ago I revived my seemingly defunct 16-50 AF using this method. Yesterday it needed revived again, but it didn't take quite as long to respond. This morning it again needed some coaxing to function normally, but not as much as the day before. I will continue this for the next couple of weeks, but if it doesn't soon start responding first time, every time as it is supposed to I will be sending it off to Uncle Vanya for a conversion.
I have had this lens since November 2012 and had the SDM repaired under a Square Trade warranty just a few months after the original Pentax warranty ran out. I am just getting tired of dealing with it.

aleonx3 · 11-18-2016, 11:23 AM

Originally posted by chuck_c

Just three days ago I revived my seemingly defunct 16-50 AF using this method. Yesterday it needed revived again, but it didn't take quite as long to respond. This morning it again needed some coaxing to function normally, but not as much as the day before. I will continue this for the next couple of weeks, but if it doesn't soon start responding first time, every time as it is supposed to I will be sending it off to Uncle Vanya for a conversion.
I have had this lens since November 2012 and had the SDM repaired under a Square Trade warranty just a few months after the original Pentax warranty ran out. I am just getting tired of dealing with it.

Just curious to know how you keep the lens when it is not being used. When I am not using the lens (lens don't get used often except on gigs and assignment) I keep the lens standing up with front element down not sideways. This way, it puts less strain on the SDM motor (to get stuck), it works for me every time when I need to use it. I have no scientific explanation for that, but it is worth a try in your case.

**UncleVanya** · 11-18-2016, 02:50 PM

Originally posted by chuck_c

Just three days ago I revived my seemingly defunct 16-50 AF using this method. Yesterday it needed revived again, but it didn't take quite as long to respond. This morning it again needed some coaxing to function normally, but not as much as the day before. I will continue this for the next couple of weeks, but if it doesn't soon start responding first time, every time as it is supposed to I will be sending it off to Uncle Vanya for a conversion.
I have had this lens since November 2012 and had the SDM repaired under a Square Trade warranty just a few months after the original Pentax warranty ran out. I am just getting tired of dealing with it.

Originally posted by aleonx3

Just curious to know how you keep the lens when it is not being used. When I am not using the lens (lens don't get used often except on gigs and assignment) I keep the lens standing up with front element down not sideways. This way, it puts less strain on the SDM motor (to get stuck), it works for me every time when I need to use it. I have no scientific explanation for that, but it is worth a try in your case.

All of my SDM lenses are stored either face up or face down. I have had zero failures but I have no idea if that is related in any way. I'm reluctant to imagine it is that simple. I am more inclined to think that some other part in the lenses that have multiple failures (or a common camera issue) is related. If there is undue drag internally or weird current/voltage fluctuations perhaps these have an impact over time on the tiny motors. In any case I don't know the answer but I do know that converted lenses seem to just work so I am happy to offer that service to those who need it.

**chuck_c** · 11-18-2016, 06:07 PM

Originally posted by aleonx3

Just curious to know how you keep the lens when it is not being used. When I am not using the lens (lens don't get used often except on gigs and assignment) I keep the lens standing up with front element down not sideways. This way, it puts less strain on the SDM motor (to get stuck), it works for me every time when I need to use it. I have no scientific explanation for that, but it is worth a try in your case.

With the exception of a couple extra long telephoto lenses, I store all of my lenses either face up or face down.

**UncleVanya** · 11-18-2016, 11:20 PM

Originally posted by chuck_c

With the exception of a couple extra long telephoto lenses, I store all of my lenses either face up or face down.

Ah well. I figured. It would be far too simple if that were the difference.

morganoh · 11-24-2016, 06:56 PM

it works for me by just pushing the AF button

but after the SDM start to work,

I try the method of turning the lens 360deg, thinking that it will make the lens smoother.
but WRONG thing to do . the O'Ring within the lens broke and it went it to the "Range indicator" of the lens.
Now my lens is struck, cannot even manual focus the lens

**UncleVanya** · 11-24-2016, 07:29 PM

Originally posted by morganoh

it works for me by just pushing the AF button

but after the SDM start to work,

I try the method of turning the lens 360deg, thinking that it will make the lens smoother.
but WRONG thing to do . the O'Ring within the lens broke and it went it to the "Range indicator" of the lens.
Now my lens is struck, cannot even manual focus the lens

Ugh. Time to send to KEH. Which specific lens is it? 16-50? 50-135? 200? 300?

LeDave · 12-08-2016, 01:42 PM

After my 16-50 works again without warm-up, I realize that a seal broke as well. There feels like air pumping out of between the gaps of the zoom ring and the meter area. It's not sucking in either, just blowing out.

The safe side is doing this, "I found another cheap way to quick fix the SDM problem. You just hold the AF button down for a couple of seconds and let go, then you hold the AF button down for a couple of seconds and let go, repeat, repeat, and repeat until it starts to move and focus again."

yyyzzz · 01-09-2017, 12:19 AM

Both motors were replaced by big $. Both failed to work again. My DA*55 is not revived. But not my DA17-70. Not sure to be

or

**UncleVanya** · 01-09-2017, 07:19 AM

Originally posted by yyyzzz

Both motors were replaced by big $. Both failed to work again. My DA*55 is not revived. But not my DA17-70. Not sure to be

or

Sorry I'm a little confused. Both of these lenses had their motors replaced and neither one works? Did the replacement fail right away? Did you have to pay for an unsuccessful repair or were these working and then they died?

01-09-2017, 12:19 AM	#44
yyyzzz Veteran Member Join Date: Mar 2009 Location: Salt Lake City, UT Photos: Gallery Posts: 509	*Worked for my DA55, but not for my DA17-70** Both motors were replaced by big $. Both failed to work again. My DA*55 is not revived. But not my DA17-70. Not sure to be or

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03-27-2016, 03:43 PM	#31
dynaudio New Member Join Date: Mar 2016 Posts: 7	Hi, Please look at my post (#7) in this thread: https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/309581-da-1...fix-check.html I can confirm working method with a small screwdriver, someone mentioned earlier. If anything I would strongly advise not to use AF to force SDM motor to move stuck parts inside the lens. Trying to so may actually overstrain the SDM motor and kill it.

03-29-2016, 11:08 AM	#32
slip Veteran Member Join Date: Oct 2006 Location: 2 hours north of toronto ontario canada Photos: Gallery \| Albums Posts: 3,537	Originally posted by GeneV If the theory is that it is just the clutch, then it should not work on the 17-70, with no quick shift clutch or screw drive. Mine only has issues above 55mm, so that is likely to be a different issue altogether. Some others have had the SDM fail entirely. the copy I am selling has the same issue. sdm seems fine, though

10-27-2016, 09:33 AM	#33
LeDave Veteran Member Join Date: Jun 2009 Location: Minneapolis - St. Paul Photos: Gallery Posts: 3,045 Original Poster	Okay, I thought I'd want to post this. After a few years of having to warming up my 16-50 to auto focus, it is no longer there. About 2 months now, I can leave the lens in my bag for a long time, and put it back on and it'll auto focus right away without having to do the warm-up tactics. The SDM works perfectly fine now. It is very strange.

11-11-2016, 10:37 AM	#34
Hmong_Xiong Junior Member Join Date: Jul 2014 Location: Colorado Posts: 45	Originally posted by LeDave Okay, I thought I'd want to post this. After a few years of having to warming up my 16-50 to auto focus, it is no longer there. About 2 months now, I can leave the lens in my bag for a long time, and put it back on and it'll auto focus right away without having to do the warm-up tactics. The SDM works perfectly fine now. It is very strange. My 16-50 does the same. It makes me want to get a new one since it's my most used lens but yet I don't want to get a new one because it still works great...when it wants to work.

11-12-2016, 03:35 AM	#35
dynaudio New Member Join Date: Mar 2016 Posts: 7	Hi, as I sad in my thread. Most likely the reason behind weird af behaviour is thickening grease. Possibly in clutch. Turning af screw with a small screwdriver back and forward few times usually solves the problem.

11-18-2016, 10:33 AM	#36
chuck_c Loyal Site Supporter Join Date: Jun 2011 Location: Westerville, OH Photos: Gallery \| Albums Posts: 1,419	Originally posted by LeDave 3/5/2016 Update: Hey guys, I found another cheap way to quick fix the SDM problem. You just hold the AF button down for a couple of seconds and let go, then you hold the AF button down for a couple of seconds and let go, repeat, repeat, and repeat until it starts to move and focus again. Just three days ago I revived my seemingly defunct 16-50 AF using this method. Yesterday it needed revived again, but it didn't take quite as long to respond. This morning it again needed some coaxing to function normally, but not as much as the day before. I will continue this for the next couple of weeks, but if it doesn't soon start responding first time, every time as it is supposed to I will be sending it off to Uncle Vanya for a conversion. I have had this lens since November 2012 and had the SDM repaired under a Square Trade warranty just a few months after the original Pentax warranty ran out. I am just getting tired of dealing with it.

11-18-2016, 11:23 AM	#37
aleonx3 Veteran Member Join Date: Jul 2007 Location: Brampton, Ontario Photos: Gallery \| Albums Posts: 3,996	Originally posted by chuck_c Just three days ago I revived my seemingly defunct 16-50 AF using this method. Yesterday it needed revived again, but it didn't take quite as long to respond. This morning it again needed some coaxing to function normally, but not as much as the day before. I will continue this for the next couple of weeks, but if it doesn't soon start responding first time, every time as it is supposed to I will be sending it off to Uncle Vanya for a conversion. I have had this lens since November 2012 and had the SDM repaired under a Square Trade warranty just a few months after the original Pentax warranty ran out. I am just getting tired of dealing with it. Just curious to know how you keep the lens when it is not being used. When I am not using the lens (lens don't get used often except on gigs and assignment) I keep the lens standing up with front element down not sideways. This way, it puts less strain on the SDM motor (to get stuck), it works for me every time when I need to use it. I have no scientific explanation for that, but it is worth a try in your case.

11-18-2016, 02:50 PM	#38
UncleVanya Loyal Site Supporter Join Date: Jul 2014 Photos: Gallery \| Albums Posts: 16,583	Originally posted by chuck_c Just three days ago I revived my seemingly defunct 16-50 AF using this method. Yesterday it needed revived again, but it didn't take quite as long to respond. This morning it again needed some coaxing to function normally, but not as much as the day before. I will continue this for the next couple of weeks, but if it doesn't soon start responding first time, every time as it is supposed to I will be sending it off to Uncle Vanya for a conversion. I have had this lens since November 2012 and had the SDM repaired under a Square Trade warranty just a few months after the original Pentax warranty ran out. I am just getting tired of dealing with it. Originally posted by aleonx3 Just curious to know how you keep the lens when it is not being used. When I am not using the lens (lens don't get used often except on gigs and assignment) I keep the lens standing up with front element down not sideways. This way, it puts less strain on the SDM motor (to get stuck), it works for me every time when I need to use it. I have no scientific explanation for that, but it is worth a try in your case. All of my SDM lenses are stored either face up or face down. I have had zero failures but I have no idea if that is related in any way. I'm reluctant to imagine it is that simple. I am more inclined to think that some other part in the lenses that have multiple failures (or a common camera issue) is related. If there is undue drag internally or weird current/voltage fluctuations perhaps these have an impact over time on the tiny motors. In any case I don't know the answer but I do know that converted lenses seem to just work so I am happy to offer that service to those who need it.

11-18-2016, 06:07 PM	#39
chuck_c Loyal Site Supporter Join Date: Jun 2011 Location: Westerville, OH Photos: Gallery \| Albums Posts: 1,419	Originally posted by aleonx3 Just curious to know how you keep the lens when it is not being used. When I am not using the lens (lens don't get used often except on gigs and assignment) I keep the lens standing up with front element down not sideways. This way, it puts less strain on the SDM motor (to get stuck), it works for me every time when I need to use it. I have no scientific explanation for that, but it is worth a try in your case. With the exception of a couple extra long telephoto lenses, I store all of my lenses either face up or face down.

11-18-2016, 11:20 PM	#40
UncleVanya Loyal Site Supporter Join Date: Jul 2014 Photos: Gallery \| Albums Posts: 16,583	Originally posted by chuck_c With the exception of a couple extra long telephoto lenses, I store all of my lenses either face up or face down. Ah well. I figured. It would be far too simple if that were the difference.

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11-24-2016, 06:56 PM	#41
morganoh New Member Join Date: Nov 2011 Posts: 2	it works for me by just pushing the AF button but after the SDM start to work, I try the method of turning the lens 360deg, thinking that it will make the lens smoother. but WRONG thing to do . the O'Ring within the lens broke and it went it to the "Range indicator" of the lens. Now my lens is struck, cannot even manual focus the lens

11-24-2016, 07:29 PM	#42
UncleVanya Loyal Site Supporter Join Date: Jul 2014 Photos: Gallery \| Albums Posts: 16,583	Originally posted by morganoh it works for me by just pushing the AF button but after the SDM start to work, I try the method of turning the lens 360deg, thinking that it will make the lens smoother. but WRONG thing to do . the O'Ring within the lens broke and it went it to the "Range indicator" of the lens. Now my lens is struck, cannot even manual focus the lens Ugh. Time to send to KEH. Which specific lens is it? 16-50? 50-135? 200? 300?

12-08-2016, 01:42 PM	#43
LeDave Veteran Member Join Date: Jun 2009 Location: Minneapolis - St. Paul Photos: Gallery Posts: 3,045 Original Poster	After my 16-50 works again without warm-up, I realize that a seal broke as well. There feels like air pumping out of between the gaps of the zoom ring and the meter area. It's not sucking in either, just blowing out. The safe side is doing this, "I found another cheap way to quick fix the SDM problem. You just hold the AF button down for a couple of seconds and let go, then you hold the AF button down for a couple of seconds and let go, repeat, repeat, and repeat until it starts to move and focus again."

01-09-2017, 07:19 AM	#45
UncleVanya Loyal Site Supporter Join Date: Jul 2014 Photos: Gallery \| Albums Posts: 16,583	Originally posted by yyyzzz Both motors were replaced by big $. Both failed to work again. My DA*55 is not revived. But not my DA17-70. Not sure to be or Sorry I'm a little confused. Both of these lenses had their motors replaced and neither one works? Did the replacement fail right away? Did you have to pay for an unsuccessful repair or were these working and then they died?