K-30 / K-50 Aperture Block Failue - Repair Solution available

**clackers** · 03-03-2017, 03:07 AM

This is all very interesting.

Since I have a K-x, a K-30 and a K-S1, maybe there'll be a day when I need this done.

Hope not, obviously.

**manmarco** · 03-03-2017, 08:19 AM

Originally posted by photogem

I have heard only that the K-70 has the same solenoid inside.
I know for sure that the K-S1 as well as the K-S2 have it as well.

I have disassembled a K50 yesterday and posted my results here:
K-50 / K-500 Aperture Solenoid fix (DIY with pics) - Page 2 - PentaxForums.com

I did not find it too difficult, it was the first time I've done it but I disassembled 3 damaged K100Ds before, using this as a kind
of training.

here a video I found of a nice gentle-man disassembling his K50:
how to fix Pentax K50 and K30 with aperture problem - YouTube

What you need is:

- very fine soldering-iron (temperature controlled is best)
- excellent fine solder (low melting point)
- PH00 screwdriver for all screws disassembling the body
- PH000 for the screw which holds the solenoid (I managed to do it with my very good PH00 but I think it would work better with a PH000)
(buy good quality, I had some cheap ones as well which I used on the K100Ds and finally broke both when I disassembled a Z-20 which
does not have a solenoid inside!)

If confident it will take about 1 hour of work alltogether to repair a K50

I took extra time to check the K50 when open, the solenoid remained stuck.
After the exchange: Perfect functioning

If you are not scared to take on this work one day, then no problem purchasing the K70.
Or you take into account that one day you have to invest about $ 120 for repair.
This anyway might happen as well with cameras of other brands.

Attached a photo of the solenoid Ricoh used 1 year ago for repair of a Pentax K-30. As you can see, it is the chinese green devil

Thanks, I probably will go with the K-70 and try the fixes here on the K-30. I had planned on selling it but not with the problem.

Not a Number · 03-03-2017, 08:57 AM

Originally posted by photogem

it is the chinese green devil

Why does everyone assume it is "Made in China"? Is it marked so? For all we know the color indicates the strength of the magnet and/or power ratings.

I've identified two suppliers of these solenoids - one is in Taiwan which produces them with black or white plastic. The South Korea only shows them in black (but that doesn't mean the other colors are not possible). So for no one has shown a black plastic example from a Pentax camera.

**photogem** · 03-03-2017, 03:51 PM

Originally posted by Not a Number

Why does everyone assume it is "Made in China"? Is it marked so?

Because it is made in China/Hongkong by:

Zhuhai Fnt Electronic Co. Ltd,
3F, Building B, Huasheng Industrial, Village, Wanzi, Zhuhai, Guangdong, 519030, CHINA

High-speed Micro Solenoid Used in Camera Shutters and DVD Player Center Processors | Global Sources

This one shown has an impendance of 2 ohms but of course they manufacture it to your very personal demand.
You just have to order several thousands of 'em!

The Japanese Solenoid uses something similar or PTFE as material and the surface of the metal parts is much smoother.
Less friction for the horseshoe/plunger when sliding in the square hollow part.

Also it can be clearly seen, inside the hole of the plunger itself there is corrosion!
The Japanese made solenoid has about 26.500 actuations use! Zero signs of corrosion.

Originally posted by Not a Number

For all we know the color indicates the strength of the magnet and/or power ratings.

And / or, which of both?

Based on which research?

Last edited by photogem; 03-04-2017 at 08:36 AM.

madphys · 03-03-2017, 11:54 PM

This becomes anecdotal...Color - I suppose manufacturer can make them pink as well - color of plastic doesn't mean anything.
Regarding metal corrosion (wear) - that is because of metal on metal action and is a clear indication that the metal itself is different in the so called "green" solenoid.

**photogem** · 03-04-2017, 08:35 AM

Originally posted by madphys

This becomes anecdotal...Color - I suppose manufacturer can make them pink as well - color of plastic doesn't mean anything.

very much so.

Ricoh sells a sensor cleaning kit called O-ICK1:
Pentax Image Sensor Cleaning Kit, O-ICK1 reviews - Pentax Camera Accessory Review Database

About one year ago it was identical to this one:
Shop ZC06000 online Gallery - Buy ZC06000 for unbeatable low prices on AliExpress.com

Aliexpress now even sells the same one in different colours.

I had the Pentax and the Aliexpress version here, identical!

Originally posted by madphys

Regarding metal corrosion (wear) - that is because of metal on metal action and is a clear indication that the metal itself is different in the so called "green" solenoid.

Yes, the metal of the green solenoid is obviously inferior.
I inspected it with my professional microscope (old style, not possible to take photos with it, otherwise I would have posted them to show this remarkeable difference)

And as mentioned, what we here call the "white solenoid", the plastic for the horse-shoe metal plunger feels much more PTFE (teflon).
Very similar to the insulation of PTFE RCA-connectors used in higher-quality audio-gear.

PTFE was used as well in special turntable bearings which last decades. The first one was the US-made Well Tempered Turntable, designed
by William Firebaugh, later copied by Franz Kuzma of the now famous Kuzma turntables. Just 4 "dots" of PTFE aligned in a special way held
the shaft of the subplatter in position. I still have one of those bearings here. Those tiny dots of PTFE did not wear at all. So I know a bit what I am talking about here, this is not just guessing.

But my guess is that Pentax dealers, Pentax repair-service-shops, distributors etc. do not like it at all if solutions for self-repair are made public.
Particular if we manage "to do it better".

Previous "official" K30, K50 and K500 repairs were done by using either the complete circuit board including the motor (see the photo I uploaded)
or recently (after they figured out what "we here and elsewhere" figured out) just changing this green solenoid against the same one, just new (and as much green behind the(ir) ears).

So dealers and distributors etc. might have strong insterest in "questioning such repairs" or "different solenoids".

The easiest way to make money these days is "Tickling fear of people".

ekip · 03-04-2017, 12:32 PM

Originally posted by photogem

very much so.

Ricoh sells a sensor cleaning kit called O-ICK1:
Pentax Image Sensor Cleaning Kit, O-ICK1 reviews - Pentax Camera Accessory Review Database

About one year ago it was identical to this one:
Shop ZC06000 online Gallery - Buy ZC06000 for unbeatable low prices on AliExpress.com

Aliexpress now even sells the same one in different colours.

I had the Pentax and the Aliexpress version here, identical!

Are those things any good at cleaning sensors? I would be afraid that they stick too much and pull out the sensor IR coating/glass as I've hear about with the sony sensors. Pentax have also stopped selling them.

**photogem** · 03-04-2017, 03:29 PM

Originally posted by ekip

Are those things any good at cleaning sensors? I would be afraid that they stick too much and pull out the sensor IR coating/glass as I've hear about with the sony sensors. Pentax have also stopped selling them.

Here in Europe you can still buy those Pentax sensor-cleaners.

I use the mentioned cheap version with success and recommended it to many people who use it with success as well.
Never heard any complain.

You need a full battery and some confidence that you manage such things. If confidence is lacking or you have two left hands, better let it be!

I never ever heard of any IR coating or glass stick to such a sensor-cleaner.
Mine does not stick that strong.

Maybe people used some tape instead? Or a vacuum-cleaner which is a bad idea anyway, the Giotto airblower extra large is way better.

Fake news? For scaring users off and make them send their cameras for an expensive cleaning job?

JPfromHolland · 03-06-2017, 07:04 AM

Hello this is JP from Holland, first time I am commenting on this forum, although I have been here many times already as a Pentax owner and fan. I have a K-50 with the Aperture failure. I dismantled an old MZ-7 and also found the part that could be used to replace the solenoid in the K-50. Is it confirmed now that this is the part that could savely be used for the K-50? See the picture.

Originally posted by altopiet

Hi, I found this, in my MZ-50, which I've already stripped for other parts...The screwdriver points to where I removed it from.

I just want to make sure that it's the part that needs replacement, before starting to strip my K-30.

(Sorry about the cellphone quality)

sys3175 · 03-06-2017, 11:33 AM - **1 Like**

Originally posted by JPfromHolland

Hello this is JP from Holland, first time I am commenting on this forum, although I have been here many times already as a Pentax owner and fan. I have a K-50 with the Aperture failure. I dismantled an old MZ-7 and also found the part that could be used to replace the solenoid in the K-50. Is it confirmed now that this is the part that could savely be used for the K-50? See the picture.

Well, it surely looks like it. Just try it and report back :-)

**photogem** · 03-07-2017, 09:49 AM - **1 Like**

Originally posted by JPfromHolland

Hello, this is JP from Holland, first time I am commenting on this forum, although I have been here many times already as a Pentax owner and fan. I have a K-50 with the Aperture failure. I dismantled an old MZ-7 and also found the part that could be used to replace the solenoid in the K-50. Is it confirmed now that this is the part that could savely be used for the K-50? See the picture.

We have been told my a member who works as a repair-person, that those solenoids of the old MZ Series for pop-up flash should work.
I would recommend to find somebody who has an ohm-meter. Then measure the impedance there, where the two cables should be soldered on.
It should be roughly 30 ohms (plus/minus 5 ohms should not matter). Then it should work.

There is not really any danger if the impedance would be different, because if lower, the solenoid coils will just burn through (fuse) and not work anymore, if higher, the solenoid will not work. So no real risk because if you have your K50 open already, you try it with a lens attached and you can see if the solenoid is working. Just don't touch the flash-capacitor!

As you unsoldered the solenoid, make sure you have a very fine tip, low melting solder (with lead!).
If you don't have a fine tip, you even can help yourself by just winding some 0,6mm diameter solid-core wire around the tip of a soldering-iron tightly.

But I'd prefer a temperature controlled unit with fine-tip. Otherwise the Ersa 15W Miltitip C15 will do.

As you already know this thread, you could have come to this conclusion actually by yourself!

JPfromHolland · 03-07-2017, 11:00 AM

Thanks Photogem, actually I do not have very good soldering skills nor do I have the right equipment, so I have just put it online to ask for somebody here (locally) who might have that skill and equipment. I hope to find someone who is willing to do that for a good price. I could have sent it to a repairshop here in Holland, but they can't guarantee less than €140,- and Pentax Holland only has a telephonenumber, and they could not offer anything else than that I could send it to Pentax in France. But they don't tell you what the final price will be. Btw, I got the solenoid from where the aperture control must be, so not from the flash. I guess it was already the same kind of mecanism!

ekip · 03-07-2017, 02:11 PM

Originally posted by photogem

We have been told my a member who works as a repair-person, that those solenoids of the old MZ Series for pop-up flash should work.
I would recommend to find somebody who has an ohm-meter. Then measure the impedance there, where the two cables should be soldered on.
It should be roughly 30 ohms (plus/minus 5 ohms should not matter). Then it should work.

There is not really any danger if the impedance would be different, because if lower, the solenoid coils will just burn through (fuse) and not work anymore, if higher, the solenoid will not work. So no real risk because if you have your K50 open already, you try it with a lens attached and you can see if the solenoid is working. Just don't touch the flash-capacitor!

As you unsoldered the solenoid, make sure you have a very fine tip, low melting solder (with lead!).
If you don't have a fine tip, you even can help yourself by just winding some 0,6mm diameter solid-core wire around the tip of a soldering-iron tightly.

But I'd prefer a temperature controlled unit with fine-tip. Otherwise the Ersa 15W Miltitip C15 will do.

As you already know this thread, you could have come to this conclusion actually by yourself!

I have a solenoid from a Toshiba/Samsung drive with 14.5 Ohm resistance from terminal to terminal. Do you think that the camera will break the solenoid?

reh321 · 03-07-2017, 04:44 PM

Looking at the simple design of this mechanism, I'm wondering if it dates to the early days of the KA-mount, to a time before stepper motors were available. My one complaint about my Super Program was how it ate through those tiny button batteries; I'm thinking now that running this mechanism would have used non-trivial amount of electricity, that perhaps batteries would have lasted longer if I had manually selected the aperture {using the aperture ring} most of the time.

ekip · 03-07-2017, 05:37 PM

Originally posted by reh321

Looking at the simple design of this mechanism, I'm wondering if it dates to the early days of the KA-mount, to a time before stepper motors were available. My one complaint about my Super Program was how it ate through those tiny button batteries; I'm thinking now that running this mechanism would have used non-trivial amount of electricity, that perhaps batteries would have lasted longer if I had manually selected the aperture {using the aperture ring} most of the time.

The solenoid only provides a small force to break the magnet contact and a spring takes over pulling it out the whole way. At some point it gets pushed back into the armature and "reloaded", probably coupled by the force of the mirror coming back down and the aperture lever being reset. It also looks like the aperture lever is sprung loaded when reset and just gets released when you take a picture. There is what looks like a plain old dc motor by the aperture block which may be what re-arms the aperture lever?

Do mordern drls use in-body steppers for autofocus?

03-06-2017, 07:04 AM	#444
JPfromHolland New Member Join Date: Sep 2015 Posts: 11	Hello this is JP from Holland, first time I am commenting on this forum, although I have been here many times already as a Pentax owner and fan. I have a K-50 with the Aperture failure. I dismantled an old MZ-7 and also found the part that could be used to replace the solenoid in the K-50. Is it confirmed now that this is the part that could savely be used for the K-50? See the picture. Originally posted by altopiet Hi, I found this, in my MZ-50, which I've already stripped for other parts...The screwdriver points to where I removed it from. I just want to make sure that it's the part that needs replacement, before starting to strip my K-30. (Sorry about the cellphone quality) Attached Images

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03-03-2017, 03:07 AM	#436
clackers Otis Memorial Pentaxian Join Date: Jul 2013 Location: Melbourne Photos: Albums Posts: 16,397	This is all very interesting. Since I have a K-x, a K-30 and a K-S1, maybe there'll be a day when I need this done. Hope not, obviously.

03-03-2017, 08:19 AM	#437
manmarco Site Supporter Join Date: May 2013 Location: Nashville, TN Posts: 19	Originally posted by photogem I have heard only that the K-70 has the same solenoid inside. I know for sure that the K-S1 as well as the K-S2 have it as well. I have disassembled a K50 yesterday and posted my results here: K-50 / K-500 Aperture Solenoid fix (DIY with pics) - Page 2 - PentaxForums.com I did not find it too difficult, it was the first time I've done it but I disassembled 3 damaged K100Ds before, using this as a kind of training. here a video I found of a nice gentle-man disassembling his K50: how to fix Pentax K50 and K30 with aperture problem - YouTube What you need is: - very fine soldering-iron (temperature controlled is best) - excellent fine solder (low melting point) - PH00 screwdriver for all screws disassembling the body - PH000 for the screw which holds the solenoid (I managed to do it with my very good PH00 but I think it would work better with a PH000) (buy good quality, I had some cheap ones as well which I used on the K100Ds and finally broke both when I disassembled a Z-20 which does not have a solenoid inside!) If confident it will take about 1 hour of work alltogether to repair a K50 I took extra time to check the K50 when open, the solenoid remained stuck. After the exchange: Perfect functioning If you are not scared to take on this work one day, then no problem purchasing the K70. Or you take into account that one day you have to invest about $ 120 for repair. This anyway might happen as well with cameras of other brands. Attached a photo of the solenoid Ricoh used 1 year ago for repair of a Pentax K-30. As you can see, it is the chinese green devil Thanks, I probably will go with the K-70 and try the fixes here on the K-30. I had planned on selling it but not with the problem.

03-03-2017, 08:57 AM	#438
Not a Number Moderator Join Date: Mar 2012 Location: Venice, CA Posts: 10,526	Originally posted by photogem it is the chinese green devil Why does everyone assume it is "Made in China"? Is it marked so? For all we know the color indicates the strength of the magnet and/or power ratings. I've identified two suppliers of these solenoids - one is in Taiwan which produces them with black or white plastic. The South Korea only shows them in black (but that doesn't mean the other colors are not possible). So for no one has shown a black plastic example from a Pentax camera.

03-03-2017, 03:51 PM	#439
photogem Site Supporter Join Date: Apr 2015 Posts: 3,520	Originally posted by Not a Number Why does everyone assume it is "Made in China"? Is it marked so? Because it is made in China/Hongkong by: Zhuhai Fnt Electronic Co. Ltd, 3F, Building B, Huasheng Industrial, Village, Wanzi, Zhuhai, Guangdong, 519030, CHINA High-speed Micro Solenoid Used in Camera Shutters and DVD Player Center Processors \| Global Sources This one shown has an impendance of 2 ohms but of course they manufacture it to your very personal demand. You just have to order several thousands of 'em! The Japanese Solenoid uses something similar or PTFE as material and the surface of the metal parts is much smoother. Less friction for the horseshoe/plunger when sliding in the square hollow part. Also it can be clearly seen, inside the hole of the plunger itself there is corrosion! The Japanese made solenoid has about 26.500 actuations use! Zero signs of corrosion. Originally posted by Not a Number For all we know the color indicates the strength of the magnet and/or power ratings. And / or, which of both? Based on which research? Last edited by photogem; 03-04-2017 at 08:36 AM.

03-03-2017, 11:54 PM	#440
madphys Forum Member Join Date: Dec 2007 Location: Riga, Latvia Posts: 98	This becomes anecdotal...Color - I suppose manufacturer can make them pink as well - color of plastic doesn't mean anything. Regarding metal corrosion (wear) - that is because of metal on metal action and is a clear indication that the metal itself is different in the so called "green" solenoid.

03-04-2017, 08:35 AM	#441
photogem Site Supporter Join Date: Apr 2015 Posts: 3,520	Originally posted by madphys This becomes anecdotal...Color - I suppose manufacturer can make them pink as well - color of plastic doesn't mean anything. very much so. Ricoh sells a sensor cleaning kit called O-ICK1: Pentax Image Sensor Cleaning Kit, O-ICK1 reviews - Pentax Camera Accessory Review Database About one year ago it was identical to this one: Shop ZC06000 online Gallery - Buy ZC06000 for unbeatable low prices on AliExpress.com Aliexpress now even sells the same one in different colours. I had the Pentax and the Aliexpress version here, identical! Originally posted by madphys Regarding metal corrosion (wear) - that is because of metal on metal action and is a clear indication that the metal itself is different in the so called "green" solenoid. Yes, the metal of the green solenoid is obviously inferior. I inspected it with my professional microscope (old style, not possible to take photos with it, otherwise I would have posted them to show this remarkeable difference) And as mentioned, what we here call the "white solenoid", the plastic for the horse-shoe metal plunger feels much more PTFE (teflon). Very similar to the insulation of PTFE RCA-connectors used in higher-quality audio-gear. PTFE was used as well in special turntable bearings which last decades. The first one was the US-made Well Tempered Turntable, designed by William Firebaugh, later copied by Franz Kuzma of the now famous Kuzma turntables. Just 4 "dots" of PTFE aligned in a special way held the shaft of the subplatter in position. I still have one of those bearings here. Those tiny dots of PTFE did not wear at all. So I know a bit what I am talking about here, this is not just guessing. But my guess is that Pentax dealers, Pentax repair-service-shops, distributors etc. do not like it at all if solutions for self-repair are made public. Particular if we manage "to do it better". Previous "official" K30, K50 and K500 repairs were done by using either the complete circuit board including the motor (see the photo I uploaded) or recently (after they figured out what "we here and elsewhere" figured out) just changing this green solenoid against the same one, just new (and as much green behind the(ir) ears). So dealers and distributors etc. might have strong insterest in "questioning such repairs" or "different solenoids". The easiest way to make money these days is "Tickling fear of people".

03-04-2017, 12:32 PM	#442
ekip Forum Member Join Date: Apr 2016 Posts: 68	Originally posted by photogem very much so. Ricoh sells a sensor cleaning kit called O-ICK1: Pentax Image Sensor Cleaning Kit, O-ICK1 reviews - Pentax Camera Accessory Review Database About one year ago it was identical to this one: Shop ZC06000 online Gallery - Buy ZC06000 for unbeatable low prices on AliExpress.com Aliexpress now even sells the same one in different colours. I had the Pentax and the Aliexpress version here, identical! Are those things any good at cleaning sensors? I would be afraid that they stick too much and pull out the sensor IR coating/glass as I've hear about with the sony sensors. Pentax have also stopped selling them.

03-04-2017, 03:29 PM	#443
photogem Site Supporter Join Date: Apr 2015 Posts: 3,520	Originally posted by ekip Are those things any good at cleaning sensors? I would be afraid that they stick too much and pull out the sensor IR coating/glass as I've hear about with the sony sensors. Pentax have also stopped selling them. Here in Europe you can still buy those Pentax sensor-cleaners. I use the mentioned cheap version with success and recommended it to many people who use it with success as well. Never heard any complain. You need a full battery and some confidence that you manage such things. If confidence is lacking or you have two left hands, better let it be! I never ever heard of any IR coating or glass stick to such a sensor-cleaner. Mine does not stick that strong. Maybe people used some tape instead? Or a vacuum-cleaner which is a bad idea anyway, the Giotto airblower extra large is way better. Fake news? For scaring users off and make them send their cameras for an expensive cleaning job?

03-06-2017, 11:33 AM - 1 Like	#445
sys3175 Forum Member Join Date: Jan 2017 Posts: 50	Originally posted by JPfromHolland Hello this is JP from Holland, first time I am commenting on this forum, although I have been here many times already as a Pentax owner and fan. I have a K-50 with the Aperture failure. I dismantled an old MZ-7 and also found the part that could be used to replace the solenoid in the K-50. Is it confirmed now that this is the part that could savely be used for the K-50? See the picture. Well, it surely looks like it. Just try it and report back :-)

03-07-2017, 09:49 AM - 1 Like	#446
photogem Site Supporter Join Date: Apr 2015 Posts: 3,520	Originally posted by JPfromHolland Hello, this is JP from Holland, first time I am commenting on this forum, although I have been here many times already as a Pentax owner and fan. I have a K-50 with the Aperture failure. I dismantled an old MZ-7 and also found the part that could be used to replace the solenoid in the K-50. Is it confirmed now that this is the part that could savely be used for the K-50? See the picture. We have been told my a member who works as a repair-person, that those solenoids of the old MZ Series for pop-up flash should work. I would recommend to find somebody who has an ohm-meter. Then measure the impedance there, where the two cables should be soldered on. It should be roughly 30 ohms (plus/minus 5 ohms should not matter). Then it should work. There is not really any danger if the impedance would be different, because if lower, the solenoid coils will just burn through (fuse) and not work anymore, if higher, the solenoid will not work. So no real risk because if you have your K50 open already, you try it with a lens attached and you can see if the solenoid is working. Just don't touch the flash-capacitor! As you unsoldered the solenoid, make sure you have a very fine tip, low melting solder (with lead!). If you don't have a fine tip, you even can help yourself by just winding some 0,6mm diameter solid-core wire around the tip of a soldering-iron tightly. But I'd prefer a temperature controlled unit with fine-tip. Otherwise the Ersa 15W Miltitip C15 will do. As you already know this thread, you could have come to this conclusion actually by yourself!

03-07-2017, 11:00 AM	#447
JPfromHolland New Member Join Date: Sep 2015 Posts: 11	Thanks Photogem, actually I do not have very good soldering skills nor do I have the right equipment, so I have just put it online to ask for somebody here (locally) who might have that skill and equipment. I hope to find someone who is willing to do that for a good price. I could have sent it to a repairshop here in Holland, but they can't guarantee less than €140,- and Pentax Holland only has a telephonenumber, and they could not offer anything else than that I could send it to Pentax in France. But they don't tell you what the final price will be. Btw, I got the solenoid from where the aperture control must be, so not from the flash. I guess it was already the same kind of mecanism!

03-07-2017, 02:11 PM	#448
ekip Forum Member Join Date: Apr 2016 Posts: 68	Originally posted by photogem We have been told my a member who works as a repair-person, that those solenoids of the old MZ Series for pop-up flash should work. I would recommend to find somebody who has an ohm-meter. Then measure the impedance there, where the two cables should be soldered on. It should be roughly 30 ohms (plus/minus 5 ohms should not matter). Then it should work. There is not really any danger if the impedance would be different, because if lower, the solenoid coils will just burn through (fuse) and not work anymore, if higher, the solenoid will not work. So no real risk because if you have your K50 open already, you try it with a lens attached and you can see if the solenoid is working. Just don't touch the flash-capacitor! As you unsoldered the solenoid, make sure you have a very fine tip, low melting solder (with lead!). If you don't have a fine tip, you even can help yourself by just winding some 0,6mm diameter solid-core wire around the tip of a soldering-iron tightly. But I'd prefer a temperature controlled unit with fine-tip. Otherwise the Ersa 15W Miltitip C15 will do. As you already know this thread, you could have come to this conclusion actually by yourself! I have a solenoid from a Toshiba/Samsung drive with 14.5 Ohm resistance from terminal to terminal. Do you think that the camera will break the solenoid?

03-07-2017, 04:44 PM	#449
reh321 Pentaxian Join Date: Nov 2014 Location: South Bend, IN, USA Photos: Gallery \| Albums Posts: 23,177	Looking at the simple design of this mechanism, I'm wondering if it dates to the early days of the KA-mount, to a time before stepper motors were available. My one complaint about my Super Program was how it ate through those tiny button batteries; I'm thinking now that running this mechanism would have used non-trivial amount of electricity, that perhaps batteries would have lasted longer if I had manually selected the aperture {using the aperture ring} most of the time.

03-07-2017, 05:37 PM	#450
ekip Forum Member Join Date: Apr 2016 Posts: 68	Originally posted by reh321 Looking at the simple design of this mechanism, I'm wondering if it dates to the early days of the KA-mount, to a time before stepper motors were available. My one complaint about my Super Program was how it ate through those tiny button batteries; I'm thinking now that running this mechanism would have used non-trivial amount of electricity, that perhaps batteries would have lasted longer if I had manually selected the aperture {using the aperture ring} most of the time. The solenoid only provides a small force to break the magnet contact and a spring takes over pulling it out the whole way. At some point it gets pushed back into the armature and "reloaded", probably coupled by the force of the mirror coming back down and the aperture lever being reset. It also looks like the aperture lever is sprung loaded when reset and just gets released when you take a picture. There is what looks like a plain old dc motor by the aperture block which may be what re-arms the aperture lever? Do mordern drls use in-body steppers for autofocus?