K-50 / K-500 Aperture Solenoid fix (DIY with pics)

**photogem** · 04-16-2019, 11:31 AM

The saying "the problem sits usually behind the camera" is a well known saying in the German speaking world which I directly translated. It is not meant as an insult.

Nobody wants to insult anybody here. Nevertheless it usually is just like that, nothing wrong with it.
I believe that you made somekind of mistake.

But.. there is a chance of about 1% against 99% that it is not the solenoid.

So yes, it can be, but I daubt it. The chance that you made a mistake is just that much higher.

And you just should accept this possibility as well. There is nothing wrong in doing so.

Again ... I don't mean to insult you.

Last edited by photogem; 04-18-2019 at 08:46 PM.

reh321 · 04-16-2019, 12:36 PM

Originally posted by Ron O

The solenoid has never moved, the aperture has never moved. It seems stuck shut.. Live view has to expose at 1/50 instead of 1/2500 to get an acceptable picture.

@photogem; understands the details in a way I don't - so he may have to address the details. Are you saying that the solenoid doesn't move at all or that the aperture doesn't move at all or that neither moves at all? If the camera is operating correctly, the lens should be open to its widest aperture before you press the shutter button, then close down to the requested opening when you press the shutter. When using a lens with aperture ring, the lens stops the closing when it reaches the requested opening; when using a lens without aperture ring, the solenoid stops the closing when it reaches the requested opening {so if the solenoid isn't working correctly, the lens closes all the way to its narrowest}. If the aperture is set to an intermediate opening {between widest and narrowest}, and the aperture isn't moving at all, that would say to me that something else may broken - or else that the solenoid is jammed in the narrowest opening setting; one way to test this is to check behavior with a lens that has an aperture ring so you could manually try both "al the way open" and "all the way closed".

Ron O · 04-18-2019, 02:20 PM

Please show me your data on the 99%(you) and the !%(me). I have heard that 99% of all statistics are made up on the spot. This is an American saying by a noted author, Mark Twain I believe but I could be wrong. We also have a saying in automotive that the problem was the nut behind the wheel. Of course this is not insulting in any way either. I admitted that I was wrong about how this particular solenoid works and I admit that I could be wrong that the solenoid is the only problem but as yet no one has proven it to me. You have never admitted being wrong at any time on this thread and always reply with a condescending remark when questioned and yet, you cannot tell me anything about the voltage that runs the solenoid or at least have not yet. Could it be you are wrong? You should just accept the possibility too. There is nothing wrong with that.
reh321, I did not see the solenoid move at all. I looked through the lens and saw a small spot of light and figured that was the aperture. When I look through my K200 and K7, I also saw that the small spot was the same no matter the aperture so the spot was no indication of how wide the aperture so looking back, I cannot say for sure that the aperture never moved. I shined a flashlight down through the lens and absolutely cannot see the aperture. The only way I can see it on my lenses (sigma 18-200, tamron 15-50) is to remove them from the camera and move the aperture lever. So are you saying the solenoid is supposed to move the aperture lever to the correct opening? I thought photogem would answer that but he never did. Another thing, when I turn on the K7 camera it makes a short kind of swish sound. When I turn on the K50 problem child, I get three or four distinct, rapid knocks. At first I thought it was the mirror but after investigation it is not.

**photogem** · 04-18-2019, 09:13 PM

Originally posted by Ron O

Originally posted by photogem

But.. there is a chance of about 1% against 99% that it is not the solenoid.

Please show me your data on the 99%(you) and the !%(me).

I did not say nor indicate that the 1% is you. I said I think clearly enough that in 99% of all cases it is just simply the solenoid which is jammed and with that, that the other possibilities of one of those cameras not working is about as low as 1%.

It has proven to me with many of those cameras I have repaired and much more of those cameras belonging to others I had helped that is was as such: Jammed solenoid.

Originally posted by Ron O

We also have a saying in automotive that the problem was the nut behind the wheel.

It is much more likely the rusty nut on the rusty screw

Originally posted by Ron O

Of course this is not insulting in any way either. I admitted that I was wrong about how this particular solenoid works and I admit that I could be wrong that the solenoid is the only problem but as yet no one has proven it to me.

Nobody needs to prove anything to you. This thread and others are there to help those who search for help with a particular problem.
And sadly sometimes we can't help. And sadly sometimes help does not arrive.
And sometimes it will be as it often is in this world: Help turns the other way round:

Originally posted by Ron O

You have never admitted being wrong at any time on this thread and always reply with a condescending remark when questioned and yet, you cannot tell me anything about the voltage that runs the solenoid or at least have not yet.

This is not a psychological competition. It is not about being right or wrong.

The voltage which runs through the solenoid corresponds exactly to the voltage of the given battery, in case you use the LI-D 109 it is exactly the voltage it supplies in its momentary state/charge. This was stated often enough when discussing the difference of using eneloops.

Originally posted by Ron O

Could it be you are wrong?

You sit behind the steering wheel of your K30, you tried to repair it, so finally it is up to you.

Originally posted by Ron O

You should just accept the possibility too. There is nothing wrong with that.

In your particular case I have never said "it is such and such" but ...:

Originally posted by photogem

Nevertheless it usually is just like that, nothing wrong with it.
I believe that you made somekind of mistake.

I think you know the meaning of "I believe"?

So lets stop discussing psychological matters, this is neither a psychological thread nor a place for magic wands.

I don't master magic wands so without having your K30 on my work-bench I cannot say anything cartain about it but just guess.
So if that is what you need for confirmation: Yes, I can only guess. But I can guess quite strong based on my experience.
And this guess remains unchanged:

1. I guess that in 99% the problem is the solenoid
2. I guess that in 99% when after a repair it does not work something went wrong during the repair.

There is nothing wrong with this and no insult.

All cameras which did not function anymore after being repaired had either

1. Been damaged during repair
or
2. Had been repaired the wrong way (sanded green solenoid) or received a new "made in China green solenoid"
or
3. as I myself experienced it, got an MZ-Series opposite polarised solenoid built in...(which I changed of course)
or
last not least....
4. had been repaired via exchange of what some name "diaphragm control block"

I have such an sample #4 here, officially repaired by Pentax/Ricoh: It had received the new "diaphragm control block" but with the green solenoid.
And it was the solenoid which had failed. I had exchanged it and the K30 works perfectly.

reh321 · 04-18-2019, 09:32 PM

Originally posted by photogem

It has proven to me with many of those cameras I have repaired and much more of those cameras belonging to others I had helped that is was as such: Jammed solenoid.

Getting back to basics: according to your experience, under what circumstances will the solenoid not move at all when trying to adjust the aperture? {taking photo or "optical preview"}?

RayeR · 04-19-2019, 06:48 PM

Solenoid plunger must be clicking and moving during shot. If not it may be mechanically blocked or no driving current passed through it (maybe blown transistor switching the coil). Here is voltage pulse I measured on coil during shot. You can chek it via scope.

**photogem** · 04-20-2019, 07:00 AM

Originally posted by reh321

Getting back to basics: according to your experience, under what circumstances will the solenoid not move at all when trying to adjust the aperture? {taking photo or "optical preview"}?

I have not tested it in all situations.

When I do test-photos with a K30 or similar which seems to have the aperture/solenoid problem, I usually use a F50/1,7 and take a few photos in AV with f=1,7
and then already can see the result, i.e. dark picture. Then 1 photo with f=16 or 22 and if then all is well, I know its the solenoid.

It was just recently that I stumbled over the remark that one could also test the camera in M-mode. I had a K500 for repair and after change of the solenoid and doing a test in AV (all was fine as usually) I did all sorts of shots in M-mode to find out that the solenoid is just not in use in M-mode.

reh321 · 04-20-2019, 07:42 AM

Originally posted by photogem

It was just recently that I stumbled over the remark that one could also test the camera in M-mode. I had a K500 for repair and after change of the solenoid and doing a test in AV (all was fine as usually) I did all sorts of shots in M-mode to find out that the solenoid is just not in use in M-mode.

In 'M' mode, do you mean that the aperture ring is used to set aperture, or do you mean 'M' set on mode dial and aperture still set from the body?

**photogem** · 04-21-2019, 01:59 AM

Originally posted by reh321

In 'M' mode, do you mean that the aperture ring is used to set aperture, or do you mean 'M' set on mode dial and aperture still set from the body?

M = Manual on the mode dial.

reh321 · 04-21-2019, 10:23 AM

Originally posted by photogem

M = Manual on the mode dial.

The solenoid is used to implement aperture opening set from the body, so it should be used anytime the lens doesn't have an aperture ring or when aperture ring is set to 'A'. With my K-30, now that the solenoid isn't working well at all, I use aperture ring to control aperture and then have to shoot in 'M' mode so I can use "green button" metering, and that works just fine despite the ailing solenoid.

added: my point being that if my K-30 works fine in 'M' mode but with aperture ring setting the aperture, I've been thinking that the solenoid isn't used in that setting, but I suppose the solenoid could just push as far as the lens would allow it to; I was hoping that someone would have definite information about solenoid use under that circumstance.

**photogem** · 04-24-2019, 09:47 PM

Next time I have a K30 or similar open, I shall check this. I only checked in M-Mode and my guess is that whenever an A-lens is not in A-position, the solenoid is not engaged at all.
It isn't engaged in M-Mode for sure, this I have verified.

slartibartfast01 · 04-24-2019, 11:06 PM

Originally posted by photogem

Next time I have a K30 or similar open, I shall check this. I only checked in M-Mode and my guess is that whenever an A-lens is not in A-position, the solenoid is not engaged at all.
It isn't engaged in M-Mode for sure, this I have verified.

Does stop down metering with the green button use the solenoid?

**photogem** · 04-24-2019, 11:43 PM

Originally posted by slartibartfast01

Does stop down metering with the green button use the solenoid?

No it doesn't! That's the whole point.

But those toothed wheels which a linked with the solenoid are in action and must be in action:

If you look into the lens and you chose (in M-Mode) any aperture-value, you can see that when you press the green button (or AE-L on those without the green button)
the aperture closes to the chose value (except wide open of course). And a 2.nd time taking the photo.

And with each push on the green button you can hear a sound. This is the sound of those wheels and the lever for the aperture. The sound comes from the springs which bring this lever and the wheels back into position. And the 2.nd time as well (inluding the sound of the shutter).

slartibartfast01 · 04-24-2019, 11:49 PM

Originally posted by photogem

No it doesn't! That's the whole point.

But those toothed wheels which a linked with the solenoid are in action and must be in action:

If you look into the lens and you chose (in M-Mode) any aperture-value, you can see that when you press the green button (or AE-L on those without the green button)
the aperture closes to the chose value (except wide open of course). And a 2.nd time taking the photo.

And with each push on the green button you can hear a sound. This is the sound of those wheels and the lever for the aperture. The sound comes from the springs which bring this lever and the wheels back into position. And the 2.nd time as well (inluding the sound of the shutter).

Thanks I always wondered about that. Does the same apply to Optical Preview ?

reh321 · 04-25-2019, 10:04 AM

Originally posted by photogem

No it doesn't! That's the whole point.

But those toothed wheels which a linked with the solenoid are in action and must be in action:

If you look into the lens and you chose (in M-Mode) any aperture-value, you can see that when you press the green button (or AE-L on those without the green button)
the aperture closes to the chose value (except wide open of course). And a 2.nd time taking the photo.

And with each push on the green button you can hear a sound. This is the sound of those wheels and the lever for the aperture. The sound comes from the springs which bring this lever and the wheels back into position. And the 2.nd time as well (inluding the sound of the shutter).

So some other source of motion moves the aperture iris - to take a photo, for green button metering, or for 'Optical Preview' - the "only" role played by the solenoid is to limit that motion when opening is set from the body?

04-16-2019, 12:36 PM	#302
reh321 Pentaxian Join Date: Nov 2014 Location: South Bend, IN, USA Photos: Gallery \| Albums Posts: 23,175	Originally posted by Ron O The solenoid has never moved, the aperture has never moved. It seems stuck shut.. Live view has to expose at 1/50 instead of 1/2500 to get an acceptable picture. @photogem; understands the details in a way I don't - so he may have to address the details. Are you saying that the solenoid doesn't move at all or that the aperture doesn't move at all or that neither moves at all? If the camera is operating correctly, the lens should be open to its widest aperture before you press the shutter button, then close down to the requested opening when you press the shutter. When using a lens with aperture ring, the lens stops the closing when it reaches the requested opening; when using a lens without aperture ring, the solenoid stops the closing when it reaches the requested opening {so if the solenoid isn't working correctly, the lens closes all the way to its narrowest}. If the aperture is set to an intermediate opening {between widest and narrowest}, and the aperture isn't moving at all, that would say to me that something else may broken - or else that the solenoid is jammed in the narrowest opening setting; one way to test this is to check behavior with a lens that has an aperture ring so you could manually try both "al the way open" and "all the way closed". Last edited by reh321; 04-16-2019 at 01:22 PM. Reason: added sentence about manual lens testing

04-19-2019, 06:48 PM	#306
RayeR Forum Member Join Date: Feb 2014 Posts: 86	Solenoid plunger must be clicking and moving during shot. If not it may be mechanically blocked or no driving current passed through it (maybe blown transistor switching the coil). Here is voltage pulse I measured on coil during shot. You can chek it via scope. Attached Images

04-21-2019, 10:23 AM	#310
reh321 Pentaxian Join Date: Nov 2014 Location: South Bend, IN, USA Photos: Gallery \| Albums Posts: 23,175	Originally posted by photogem M = Manual on the mode dial. The solenoid is used to implement aperture opening set from the body, so it should be used anytime the lens doesn't have an aperture ring or when aperture ring is set to 'A'. With my K-30, now that the solenoid isn't working well at all, I use aperture ring to control aperture and then have to shoot in 'M' mode so I can use "green button" metering, and that works just fine despite the ailing solenoid. added: my point being that if my K-30 works fine in 'M' mode but with aperture ring setting the aperture, I've been thinking that the solenoid isn't used in that setting, but I suppose the solenoid could just push as far as the lens would allow it to; I was hoping that someone would have definite information about solenoid use under that circumstance. Last edited by reh321; 04-22-2019 at 10:51 AM.

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04-16-2019, 11:31 AM	#301
photogem Site Supporter Join Date: Apr 2015 Posts: 3,517	The saying "the problem sits usually behind the camera" is a well known saying in the German speaking world which I directly translated. It is not meant as an insult. Nobody wants to insult anybody here. Nevertheless it usually is just like that, nothing wrong with it. I believe that you made somekind of mistake. But.. there is a chance of about 1% against 99% that it is not the solenoid. So yes, it can be, but I daubt it. The chance that you made a mistake is just that much higher. And you just should accept this possibility as well. There is nothing wrong in doing so. Again ... I don't mean to insult you. Last edited by photogem; 04-18-2019 at 08:46 PM.

04-18-2019, 02:20 PM	#303
Ron O New Member Join Date: Apr 2019 Location: southeast Colorado Posts: 14	Please show me your data on the 99%(you) and the !%(me). I have heard that 99% of all statistics are made up on the spot. This is an American saying by a noted author, Mark Twain I believe but I could be wrong. We also have a saying in automotive that the problem was the nut behind the wheel. Of course this is not insulting in any way either. I admitted that I was wrong about how this particular solenoid works and I admit that I could be wrong that the solenoid is the only problem but as yet no one has proven it to me. You have never admitted being wrong at any time on this thread and always reply with a condescending remark when questioned and yet, you cannot tell me anything about the voltage that runs the solenoid or at least have not yet. Could it be you are wrong? You should just accept the possibility too. There is nothing wrong with that. reh321, I did not see the solenoid move at all. I looked through the lens and saw a small spot of light and figured that was the aperture. When I look through my K200 and K7, I also saw that the small spot was the same no matter the aperture so the spot was no indication of how wide the aperture so looking back, I cannot say for sure that the aperture never moved. I shined a flashlight down through the lens and absolutely cannot see the aperture. The only way I can see it on my lenses (sigma 18-200, tamron 15-50) is to remove them from the camera and move the aperture lever. So are you saying the solenoid is supposed to move the aperture lever to the correct opening? I thought photogem would answer that but he never did. Another thing, when I turn on the K7 camera it makes a short kind of swish sound. When I turn on the K50 problem child, I get three or four distinct, rapid knocks. At first I thought it was the mirror but after investigation it is not.

04-18-2019, 09:13 PM	#304
photogem Site Supporter Join Date: Apr 2015 Posts: 3,517	Originally posted by Ron O Originally posted by photogem But.. there is a chance of about 1% against 99% that it is not the solenoid. Please show me your data on the 99%(you) and the !%(me). I did not say nor indicate that the 1% is you. I said I think clearly enough that in 99% of all cases it is just simply the solenoid which is jammed and with that, that the other possibilities of one of those cameras not working is about as low as 1%. It has proven to me with many of those cameras I have repaired and much more of those cameras belonging to others I had helped that is was as such: Jammed solenoid. Originally posted by Ron O We also have a saying in automotive that the problem was the nut behind the wheel. It is much more likely the rusty nut on the rusty screw Originally posted by Ron O Of course this is not insulting in any way either. I admitted that I was wrong about how this particular solenoid works and I admit that I could be wrong that the solenoid is the only problem but as yet no one has proven it to me. Nobody needs to prove anything to you. This thread and others are there to help those who search for help with a particular problem. And sadly sometimes we can't help. And sadly sometimes help does not arrive. And sometimes it will be as it often is in this world: Help turns the other way round: Originally posted by Ron O You have never admitted being wrong at any time on this thread and always reply with a condescending remark when questioned and yet, you cannot tell me anything about the voltage that runs the solenoid or at least have not yet. This is not a psychological competition. It is not about being right or wrong. The voltage which runs through the solenoid corresponds exactly to the voltage of the given battery, in case you use the LI-D 109 it is exactly the voltage it supplies in its momentary state/charge. This was stated often enough when discussing the difference of using eneloops. Originally posted by Ron O Could it be you are wrong? You sit behind the steering wheel of your K30, you tried to repair it, so finally it is up to you. Originally posted by Ron O You should just accept the possibility too. There is nothing wrong with that. In your particular case I have never said "it is such and such" but ...: Originally posted by photogem Nevertheless it usually is just like that, nothing wrong with it. I believe that you made somekind of mistake. I think you know the meaning of "I believe"? So lets stop discussing psychological matters, this is neither a psychological thread nor a place for magic wands. I don't master magic wands so without having your K30 on my work-bench I cannot say anything cartain about it but just guess. So if that is what you need for confirmation: Yes, I can only guess. But I can guess quite strong based on my experience. And this guess remains unchanged: 1. I guess that in 99% the problem is the solenoid 2. I guess that in 99% when after a repair it does not work something went wrong during the repair. There is nothing wrong with this and no insult. All cameras which did not function anymore after being repaired had either 1. Been damaged during repair or 2. Had been repaired the wrong way (sanded green solenoid) or received a new "made in China green solenoid" or 3. as I myself experienced it, got an MZ-Series opposite polarised solenoid built in...(which I changed of course) or last not least.... 4. had been repaired via exchange of what some name "diaphragm control block" I have such an sample #4 here, officially repaired by Pentax/Ricoh: It had received the new "diaphragm control block" but with the green solenoid. And it was the solenoid which had failed. I had exchanged it and the K30 works perfectly.

04-18-2019, 09:32 PM	#305
reh321 Pentaxian Join Date: Nov 2014 Location: South Bend, IN, USA Photos: Gallery \| Albums Posts: 23,175	Originally posted by photogem It has proven to me with many of those cameras I have repaired and much more of those cameras belonging to others I had helped that is was as such: Jammed solenoid. Getting back to basics: according to your experience, under what circumstances will the solenoid not move at all when trying to adjust the aperture? {taking photo or "optical preview"}?

04-20-2019, 07:00 AM	#307
photogem Site Supporter Join Date: Apr 2015 Posts: 3,517	Originally posted by reh321 Getting back to basics: according to your experience, under what circumstances will the solenoid not move at all when trying to adjust the aperture? {taking photo or "optical preview"}? I have not tested it in all situations. When I do test-photos with a K30 or similar which seems to have the aperture/solenoid problem, I usually use a F50/1,7 and take a few photos in AV with f=1,7 and then already can see the result, i.e. dark picture. Then 1 photo with f=16 or 22 and if then all is well, I know its the solenoid. It was just recently that I stumbled over the remark that one could also test the camera in M-mode. I had a K500 for repair and after change of the solenoid and doing a test in AV (all was fine as usually) I did all sorts of shots in M-mode to find out that the solenoid is just not in use in M-mode.

04-20-2019, 07:42 AM	#308
reh321 Pentaxian Join Date: Nov 2014 Location: South Bend, IN, USA Photos: Gallery \| Albums Posts: 23,175	Originally posted by photogem It was just recently that I stumbled over the remark that one could also test the camera in M-mode. I had a K500 for repair and after change of the solenoid and doing a test in AV (all was fine as usually) I did all sorts of shots in M-mode to find out that the solenoid is just not in use in M-mode. In 'M' mode, do you mean that the aperture ring is used to set aperture, or do you mean 'M' set on mode dial and aperture still set from the body?

04-21-2019, 01:59 AM	#309
photogem Site Supporter Join Date: Apr 2015 Posts: 3,517	Originally posted by reh321 In 'M' mode, do you mean that the aperture ring is used to set aperture, or do you mean 'M' set on mode dial and aperture still set from the body? M = Manual on the mode dial.

04-24-2019, 09:47 PM	#311
photogem Site Supporter Join Date: Apr 2015 Posts: 3,517	Next time I have a K30 or similar open, I shall check this. I only checked in M-Mode and my guess is that whenever an A-lens is not in A-position, the solenoid is not engaged at all. It isn't engaged in M-Mode for sure, this I have verified.

04-24-2019, 11:06 PM	#312
slartibartfast01 Pentaxian Join Date: May 2015 Photos: Gallery Posts: 1,931	Originally posted by photogem Next time I have a K30 or similar open, I shall check this. I only checked in M-Mode and my guess is that whenever an A-lens is not in A-position, the solenoid is not engaged at all. It isn't engaged in M-Mode for sure, this I have verified. Does stop down metering with the green button use the solenoid?

04-24-2019, 11:43 PM	#313
photogem Site Supporter Join Date: Apr 2015 Posts: 3,517	Originally posted by slartibartfast01 Does stop down metering with the green button use the solenoid? No it doesn't! That's the whole point. But those toothed wheels which a linked with the solenoid are in action and must be in action: If you look into the lens and you chose (in M-Mode) any aperture-value, you can see that when you press the green button (or AE-L on those without the green button) the aperture closes to the chose value (except wide open of course). And a 2.nd time taking the photo. And with each push on the green button you can hear a sound. This is the sound of those wheels and the lever for the aperture. The sound comes from the springs which bring this lever and the wheels back into position. And the 2.nd time as well (inluding the sound of the shutter).

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04-24-2019, 11:49 PM	#314
slartibartfast01 Pentaxian Join Date: May 2015 Photos: Gallery Posts: 1,931	Originally posted by photogem No it doesn't! That's the whole point. But those toothed wheels which a linked with the solenoid are in action and must be in action: If you look into the lens and you chose (in M-Mode) any aperture-value, you can see that when you press the green button (or AE-L on those without the green button) the aperture closes to the chose value (except wide open of course). And a 2.nd time taking the photo. And with each push on the green button you can hear a sound. This is the sound of those wheels and the lever for the aperture. The sound comes from the springs which bring this lever and the wheels back into position. And the 2.nd time as well (inluding the sound of the shutter). Thanks I always wondered about that. Does the same apply to Optical Preview ?

04-25-2019, 10:04 AM	#315
reh321 Pentaxian Join Date: Nov 2014 Location: South Bend, IN, USA Photos: Gallery \| Albums Posts: 23,175	Originally posted by photogem No it doesn't! That's the whole point. But those toothed wheels which a linked with the solenoid are in action and must be in action: If you look into the lens and you chose (in M-Mode) any aperture-value, you can see that when you press the green button (or AE-L on those without the green button) the aperture closes to the chose value (except wide open of course). And a 2.nd time taking the photo. And with each push on the green button you can hear a sound. This is the sound of those wheels and the lever for the aperture. The sound comes from the springs which bring this lever and the wheels back into position. And the 2.nd time as well (inluding the sound of the shutter). So some other source of motion moves the aperture iris - to take a photo, for green button metering, or for 'Optical Preview' - the "only" role played by the solenoid is to limit that motion when opening is set from the body?