[TV95]

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This can be misleading:

The solenoid itself is an electro-magnet with an inserted quite strong tiny permanent magnet (top of the solenoid), I marked it red on the attached photo.

The horseshoe at the bottom of the solenoid itself is not a magnet but made out of magnetic material!

My bad, you're right indeed!

[chucho]

i have tried, followed all steps in the video and the camera came alive!!!!

[vladmoll]

I measure green solenoid and white solenoid. There are same 3.1 oma. I cant figure why one work but other not.

[slartibartfast01]

I measure green solenoid and white solenoid. There are same 3.1 oma. I cant figure why one work but other not.

Sorry to have to ask but what does 3.1 oma mean.

[ekip]

I have just fixed mine by simply removing the horseshoe for a while and then putting it back. No sanding or changing of parts.

The only thing that I don't know about is why the aperture stops down to around f/5.6 on my 50mm f/1.7 (in 'A') when in movie mode and live view. When I take the picture or record it resets the mirror and goes to the correct aperture.

If I use the ring instead, it will sometimes briefly pause then close down to f/22 when opening live view. Photos from it and the kit lens are all spot on.

For anyone taking theirs apart make sure to discharge the cap. It's 330v 240uf.

[vladmoll]

Sorry to have to ask but what does 3.1 oma mean.

Resistens of magnet coil who push horshe shue down.

[ekip]

Getting some underexposed now but not at the smallest aperture like I used to. First shot is sometimes underexposed.

[photogem]

I measure green solenoid and white solenoid. There are same 3.1 oma. I cant figure why one work but other not.

Careful, you need to be precise, this can lead others into confusion.
I guess you measure the right way but you have either a typographical error here or your meter was set the wrong way:

The DC resistance of the solenoid is 31 ohms (sometimes it is 29 or 30 ohms, but this is not important, +/-10% would be fine!)

This is valid for both solenoids, the green version and the white version "made in Japan"

---------- Post added 07-28-17 at 11:49 PM ----------

ekip wrote May 20th:

I have a cd rom solenoid and it measures 15 ohm. Could you also just put a resistor in line with it to bring the resistance up to 30? Would a resistor'd solenoid have equal ejecting force as the Pentax one?

ekip wrote July 3rd:

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?

ekip wrote July 29th:

I have just fixed mine by simply removing the horseshoe for a while and then putting it back. No sanding or changing of parts.

The only thing that I don't know about is why the aperture stops down to around f/5.6 on my 50mm f/1.7 (in 'A') when in movie mode and live view. When I take the picture or record it resets the mirror and goes to the correct aperture.

If I use the ring instead, it will sometimes briefly pause then close down to f/22 when opening live view. Photos from it and the kit lens are all spot on.

For anyone taking theirs apart make sure to discharge the cap. It's 330v 240uf.

You participated for quite a while now and you do know that there are solenoids which fit (and measure around 30-31 ohms) and you know the procedure.
So why the heck do you make the effort to get a white solenoid (which turns out to have the wrong value, i.e. 14,5 or 15 ohms) and then you
open your body and you "give it a snooze", hope for some magic and then you undertake all this work for .... NOTHING!

Strange way of dealing with this problem.

For god's sake: ENOUGH Instructions have been given, repeatedly it was even warned, that filing/sanding or soldering the horseshoe of the solenoid is not the right way ....

It might be that the error is in the horseshoe that it is too strongly magnetized and holds too tight. Could be.
But taking it out will not really remove the magnesism. If you have a screwdriver with a magnetised tip, you have to demagnetise it.
But it can easely get magnetised again.

The problem with sanding / filing or soldering as I see it is that the force on the mechanism will then be different.
But I can only guess all this. I have not filed nor soldered but only replaced the solenoid with the white one and right now.... because people
know about it and I am a member in a photoclub people asked me to help and I have repaired right now 7 x Pentax K30 and 1 x Pentax K50.
One K30 was beyond repair, continuous shooting damaged to much and it had very high shuttercount. All others work very well
and one has been used very intensivly.

So for gods sake, either do it proberly but stop waiting for the resurrection of your horseshoe

[ekip]

Careful, you need to be precise, this can lead others into confusion.
I guess you measure the right way but you have either a typographical error here or your meter was set the wrong way:

The DC resistance of the solenoid is 31 ohms (sometimes it is 29 or 30 ohms, but this is not important, +/-10% would be fine!)

This is valid for both solenoids, the green version and the white version "made in Japan"

---------- Post added 07-28-17 at 11:49 PM ----------

ekip wrote May 20th:

ekip wrote July 3rd:


ekip wrote July 29th:


You participated for quite a while now and you do know that there are solenoids which fit (and measure around 30-31 ohms) and you know the procedure.
So why the heck do you make the effort to get a white solenoid (which turns out to have the wrong value, i.e. 14,5 or 15 ohms) and then you
open your body and you "give it a snooze", hope for some magic and then you undertake all this work for .... NOTHING!

Strange way of dealing with this problem.

For god's sake: ENOUGH Instructions have been given, repeatedly it was even warned, that filing/sanding or soldering the horseshoe of the solenoid is not the right way ....

It might be that the error is in the horseshoe that it is too strongly magnetized and holds too tight. Could be.
But taking it out will not really remove the magnesism. If you have a screwdriver with a magnetised tip, you have to demagnetise it.
But it can easely get magnetised again.

The problem with sanding / filing or soldering as I see it is that the force on the mechanism will then be different.
But I can only guess all this. I have not filed nor soldered but only replaced the solenoid with the white one and right now.... because people
know about it and I am a member in a photoclub people asked me to help and I have repaired right now 7 x Pentax K30 and 1 x Pentax K50.
One K30 was beyond repair, continuous shooting damaged to much and it had very high shuttercount. All others work very well
and one has been used very intensivly.

So for gods sake, either do it proberly but stop waiting for the resurrection of your horseshoe

Which bodies have the white solenoids that are the same specs as the green ones?

[aezarien]

---------- Post added 07-29-17 at 10:27 PM ----------

[/COLOR]

Which bodies have the white solenoids that are the same specs as the green ones?

I replaced mine with the solenoid from the pop-up flash of an *istDS (some have two solenoids, one for aperture, one for flash). I actually sanded the horseshoe in the faulty one and put it in the istDS for the pop-up flash. Both cameras are now fully functional and I seriously could not care less if the pop-up flash fails on either one. I never use them anyway.

[photogem]

Which bodies have the white solenoids that are the same specs as the green ones?

My thought here is, that instead of spending the money for a *ist-DL or similar, which either is more expensive than the solenoid in ebay
or... if damaged, you don't know really what is damaged plus the extra work of dismantling such a camera, why not buy it in ebay
and thus know, that this is tested and guaranteed the correct one.

Of course, if I would have an *ist DS anyway, I would do exactly the same as aezarian.
The *ist DS and particular the DS2 still makes nice photos. Has the CCD Sensor which found its peak in the K10D (which has
1 and not 2 solenoids inside, as it has mechanical flash release like the K7 and K5, I just opened a damaged one yesterday)

I have no idea with CD-ROM Drives would have the right one.
I also tried the solenoid from the MZ-Series, measurements were 100% correct but it did't work.
But as I recall it rightly others had different experiences here?

[aezarien]

Yeah, I already had the *istDS, which I originally purchased new and knew the flash solenoid was barely used. I wasn't sure I wanted to take my DS apart, because I still use it in tandum with the k-50, so I did look for a used one first. I found a few cheap "for parts" cameras on ebay, but never could get a clear answer as to what was wrong with them. Plus, unlike the camera I already owned, no telling how "used" those parts were. Personally, I did not see an option which did not have some level of risk associated with it so I chose the option which had the closest thing to a known quantity to work with. Very slimly, that was knowing I had a part which had been through the same environmental stressors the k-50 went through and still functioned. I made the choice not to replace the part with the green one based merely on conjecture and personal experience. My husband works with small parts like this on a regular basis. Generally speaking, if they are different colors, it has something to do with how the specification varies. I do not have the time, nor the ambition to explore what the differences may be, although I did attempt to go down that avenue of research previously. I do know whatever the specs are on this green one combined with the environmental stressors I put on the camera, it failed. I have also seen where people have mentioned theirs was replaced with the green part and it failed later down the road. Perhaps that is the deeper question, though. Other than "they were made in China" what differentiates the parts? Perhaps it could be the alloys in the metal parts. Maybe that was answered at some point and I missed it. Anyway, that was what seemed logical to me, at the time.

[The Squirrel Mafia]

D'oh! It looks like my black K-50 is starting to develop the dreaded aperture motor issue. After not using the camera for about a week or so, there's a 50/50 chance that the first shot will come out dark, but every single shot after that is fine, until I use the camera again a few days later.

Pentax K-30 K-50 Genuine Aperture Solenoid Plunger Part - Made in Japan - | eBay

^ I think I'm going to spring for one of these & attempt the fix myself. I'll be going to Japan this September & I'll be damned if it fails there. Hahaha!

[umuttepe]

I have a K-S2, and it has problems setting the aperture right. I have to take 20+ pictures quickly to make it work. I only have problems with new lenses. I have no problems with older lenses. The stiffness of the aperture lever is NOT the problem. I have Pentax-M lenses, and they have much stiffer aperture levers. (I have tested the levers by pulling them with weights). Besides, the camera does not push the lever when a picture is taken. The camera releases the lever. There is no problem with the aperture block, no mechanical problems. If the camera can release and push back the lever on older lenses, it sure can release and push back on newer lenses. THE PROBLEM HAS TO BE A SOFTWARE PROBLEM.

[photogem]

Generally speaking, if they are different colors, it has something to do with how the specification varies. I do not have the time, nor the ambition to explore what the differences may be, although I did attempt to go down that avenue of research previously. I do know whatever the specs are on this green one combined with the environmental stressors I put on the camera, it failed. I have also seen where people have mentioned theirs was replaced with the green part and it failed later down the road. Perhaps that is the deeper question, though. Other than "they were made in China" what differentiates the parts? Perhaps it could be the alloys in the metal parts. Maybe that was answered at some point and I missed it. Anyway, that was what seemed logical to me, at the time.

Several people have invested quite a lot of research in finding out what the culprit is.
There is no definite answer, but we came at least quite close to identify the bug.
You have to research this thread and one or two other threads.

But postings like this one are misleading:

Title: Has nothing to do with any mechanical part!

NONSENSE: The solenoid IS A MECHANICAL PART! If this part was replaced with the right one, all proper repaired cameras work again!

This is your first post in this thread and forum.
You have a K-S2 and came across this well known problem.
But then you barge in with strong statements such as your title which is based on "which research"?

I have a K-S2, and it has problems setting the aperture right. I have to take 20+ pictures quickly to make it work. I only have problems with new lenses. I have no problems with older lenses.

Define "new lenses"! DA or DA L lenses or AF lenses such as F or FA included?

The stiffness of the aperture lever is NOT the problem. I have Pentax-M lenses, and they have much stiffer aperture levers. (I have tested the levers by pulling them with weights). Besides, the camera does not push the lever when a picture is taken. The camera releases the lever.

That is a useful observation/argument which helps, but then you bring in this statement:

There is no problem with the aperture block, no mechanical problems. If the camera can release and push back the lever on older lenses, it sure can release and push back on newer lenses.

Then the white solenoid should not work either! But it does! So what now?!

THE PROBLEM HAS TO BE A SOFTWARE PROBLEM.

EVERY DLSR BODY WHICH HAD BEEN PROPER REPAIRED WORKS WITH THE PROPER SOLENOID
AND DID NEVER NEED ANY CHANGE IN SOFTWARE

BESIDES: WE ARE SPEAKING OF SIX CAMERAS: K30-50-500 K-S1-S2 and K70 which have the green solenoid
Aside of the K70 which is too new on the market .... all others have developed this problem.

If users did not insist on this method:

I have to take 20+ pictures quickly to make it work

which leeds to further mechanical problems, all could be repaired by replacing the solenoid and all work.

So if you bring statements: BRING something which indicates at least towards a sensible direction.

Otherwise it is not only pretty useless but more or less misleading!