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06-16-2019, 06:53 AM   #871
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Often people recommend filing/sanding/grinding the plunger of the green China-solenoid which was supposed to do the trick.

Well, for some it did but for many it didn't.


The reasons for this are just the plunger alone.... but I was able to compare


- the latest solenoid of a K-70
- the latest solenoid used for official repair of a K-30 (which failed again due to the solenoid)
- the solenoid of a K-S1


and


- the well regarded "made in Japan solenoid".

It shows the steps Ricoh implied in having the solenoid problem solved and why still some K-S1's and K-S2's and very few K-70's did fail
and what could be done to solve this finally.


Because this is important for those who own a K-70 or plan to buy it (as it is the actual Pentax using this solenoid!)

I have written it the K-70 section with many photos documenting the difference.

You can read it all HERE

06-30-2019, 03:46 AM   #872
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Today I plucked up courage and disassembled my K-30 camera, using the tips on the forum, as well as this video:
pulled out the solenoid, slightly polished and demagnetized (well. just in case, although it may not be necessary) using the device for magnetizing and demagnetizing screwdrivers and everything began to work as before
It was not difficult.
But I don't know how long it will last ...and while i'm happy

Last edited by Martin Stu; 06-30-2019 at 03:56 AM.
06-30-2019, 11:13 AM   #873
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QuoteOriginally posted by Martin Stu Quote
Today I plucked up courage and disassembled my K-30 camera, using the tips on the forum, as well as this video: How to fix Pentax K-50 (K-30) aperture - YouTube pulled out the solenoid, slightly polished and demagnetized (well. just in case, although it may not be necessary) using the device for magnetizing and demagnetizing screwdrivers and everything began to work as before
It was not difficult.
But I don't know how long it will last ...and while i'm happy
Let us know how it goes - every experiment is useful ... knowing what doesn't work is just as important as knowing what does work.
06-30-2019, 06:58 PM   #874
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reh321, I used these tools - screwdriver (so that the screws do not fall I specifically magnetized a screwdriver), tweezers, magnetize-demagnetize (I took the horseshoe with tweezers and moved it a little demagnetizing) and magnifier
I forgot to say - the solenoid is mounted with one screw on the right (I thought on two screws, but it turned out on one)
and finally, you need nail polish, after you screw the solenoid in place, apply a little varnish to the screw head (as shown in the above video), probably it is necessary instead of glue

ruler - to better represent size

I gladly made this photo with a repaired camera.

Attached Images
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PENTAX K-30  Photo 

Last edited by Martin Stu; 08-03-2019 at 10:22 AM.
08-14-2019, 11:40 AM   #875
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QuoteOriginally posted by Martin Stu Quote
reh321, I used these tools - screwdriver (so that the screws do not fall I specifically magnetized a screwdriver), tweezers, magnetize-demagnetize (I took the horseshoe with tweezers and moved it a little demagnetizing) and magnifier
I forgot to say - the solenoid is mounted with one screw on the right (I thought on two screws, but it turned out on one)
and finally, you need nail polish, after you screw the solenoid in place, apply a little varnish to the screw head (as shown in the above video), probably it is necessary instead of glue

ruler - to better represent size

I gladly made this photo with a repaired camera.
Hello Martin,


Have you had any problem with the camera since you repaired it?
08-14-2019, 12:20 PM   #876
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I sanded and "cleaned" (WD-40 to clean it after sanding) my horseshoe in the K-50 20 months ago.

Mind you, I am mostly a Manual shooter, with the occasional A-setting lens (to which the aperture block is needed) = no issues to report.
08-14-2019, 12:45 PM   #877
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QuoteOriginally posted by edom31 Quote
I sanded and "cleaned" (WD-40 to clean it after sanding) my horseshoe in the K-50 20 months ago.

Mind you, I am mostly a Manual shooter, with the occasional A-setting lens (to which the aperture block is needed) = no issues to report.
Glad to hear that!

And did you sand only the lower flat part of the horse shoe? Or did you make some kind of chamfers?
08-14-2019, 02:33 PM   #878
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QuoteOriginally posted by k50er Quote
Glad to hear that!

And did you sand only the lower flat part of the horse shoe? Or did you make some kind of chamfers?
I was very delicate about it. I tried to chamfer a bit but I did not over kill - less is more. Also I was not very worried about having it "perfect" - I do believe that the lubricant cleanse provided also helped (nothing was wet when reassembling).

I do think it will go bad again - I use my k50 daily now, but when the aperture failed, I note it after the k50 sitting in the closet for months... Daily use is important for the fix to last. If it seats, it will lokely relapse.

08-14-2019, 03:03 PM   #879
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QuoteOriginally posted by edom31 Quote
I was very delicate about it. I tried to chamfer a bit but I did not over kill - less is more. Also I was not very worried about having it "perfect" - I do believe that the lubricant cleanse provided also helped (nothing was wet when reassembling).
I think so too. In my opinion the lubricant helps to reduce wearing between different pieces of the solenoid, or at least, it maintains the horseshoe clean so as it can move more freely inside the coils.


QuoteOriginally posted by edom31 Quote
I do think it will go bad again - I use my k50 daily now, but when the aperture failed, I note it after the k50 sitting in the closet for months... Daily use is important for the fix to last. If it seats, it will lokely relapse.
It is not the first time I hear that not using the camera for a quite long time can lead to a failure much quicker than using it more often, and it could be because you don't leave the solenoid to be magnetized by using the camera every day.

Apart from that, and taking into account that it is not a permanent repair and that you have done at home, 20 months (almost 2 years) without dark images is quite impressive Congrats!

Maybe doesn't matter but... when you noticed the aperture problem, the camera was in the closet with the battery installed?
08-14-2019, 06:29 PM   #880
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QuoteOriginally posted by k50er Quote
Apart from that, and taking into account that it is not a permanent repair and that you have done at home, 20 months (almost 2 years) without dark images is quite impressive Congrats!
Thanks - it does feel good... I do not have the cash for a new body right now (I'd get a used K-3 if I'd get anything right now - K-3 rather than K-3ii).

QuoteOriginally posted by k50er Quote
Maybe doesn't matter but... when you noticed the aperture problem, the camera was in the closet with the battery installed?
Battery was installed yes. I am not so cautious about storing battery-operated items - that is a flaw.
08-15-2019, 03:59 AM   #881
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QuoteOriginally posted by k50er Quote
Have you had any problem with the camera since you repaired it?
Hello, k50er
there were no more problems, everything is fine
when I pulled out the horseshoe, it seemed to me that she somehow sits firmly (as if it stuck), and when, after the manipulations, put her in her place, she already moved easily

Before the appearance of the “Malevich's Black Square”, for a long time I did not use the camera, the camera was always with a battery, then I took out the camera, charged the battery, and “Malevich Square” was my masterpiece! It all started ...

Last edited by Martin Stu; 08-15-2019 at 04:40 AM.
08-15-2019, 05:55 AM   #882
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Nobody wants any lube inside the solenoid, the plunger slams inside and will eventually push the lube outside into places you don't want any liquid no matter what sort of.
Kind of lubing the WR abilities inside out.


Anyway, even Ricoh at times applied the sanding method but changed the solenoid for better latest in the K-70 (although I think it was already earlier on ).

The horseshoe/plunger has an anodised surface. If this surface is hurt, it can start to corrode.

I have shown this HERE and I have seen worse corrosion

on some sanded plungers.


But I also have seen sanded plungers which showed no sign of corrosion, nevertheless they failed again (those I saw, that's why they came into my house)
Sanding is a cheap option, no question, but it is not save!


The important question remains: As long as you can get the original "white made in Japan Solenoid", why invest all this work and then be "mean with ingredients"?
Doesn't make sense to me. Many had to do the repair again and in some cases due to further problems caused by this sanded solenoid the body was beyond repair.



Here a photo of a horseshoe with corrosion which failed again:



Even this method which an official Pentax repairplace applied failed again.

This was by the way the 2nd repair, the first was on warranty and failed as well. So this time they tried to decrease the surface by inscribing those notches:



A clever attempt I find and yet it failed again.
Clever because opposite to chamfering the plunger this way at least the contact with the sides of the plastic-housing does not change to the worse, i.e. becomes more wobbly which I explained in detail HERE in the Manual solenoid replacement Pentax K30 The green PET body anyway is far inferior to the PTFE body of the white Japan-Solenoid. This body acts as the bearing for the two plunger-shafts. They need to slide in and out with presicion. Chamfering the corners of the plunger lessens the surface on the side. The green PET body anyway has more tolerance than the white PTFE body.

Last edited by photogem; 08-15-2019 at 06:08 AM.
08-15-2019, 08:59 AM - 2 Likes   #883
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Thank you all for your answers!


QuoteOriginally posted by edom31 Quote
Thanks - it does feel good... I do not have the cash for a new body right now (I'd get a used K-3 if I'd get anything right now - K-3 rather than K-3ii).

Battery was installed yes. I am not so cautious about storing battery-operated items - that is a flaw.
Normally I have the camera with the battery installed, but if I know I'm not going to use it for a long time, I prefer to remove it from the camera. Theoretically, doing this or not doesn't affect to the solenoid, because the power switch is between them, but who knows exactly

QuoteOriginally posted by Martin Stu Quote
Hello, k50er
there were no more problems, everything is fine
when I pulled out the horseshoe, it seemed to me that she somehow sits firmly (as if it stuck), and when, after the manipulations, put her in her place, she already moved easily

Before the appearance of the “Malevich's Black Square”, for a long time I did not use the camera, the camera was always with a battery, then I took out the camera, charged the battery, and “Malevich Square” was my masterpiece! It all started ...
"Malevich's Black Square"... Good artistic reference for this problem

When you said "polish" in the previous message, what do you mean? Very good cleaned? Sanded?



QuoteOriginally posted by photogem Quote
Nobody wants any lube inside the solenoid, the plunger slams inside and will eventually push the lube outside into places you don't want any liquid no matter what sort of.
Kind of lubing the WR abilities inside out.
Of course it is a bad idea to install a solenoid with liquid lube in the camera, I was thinking in a some kind of solid lube. However, I think it doesn't hurt cleaning the horseshoe with WD40 (or other kind of cleaner) if you have uninstalled the solenoid, because this way you can remove the dust, grease, etc the solenoid could have. Of course, if this cleaning is done, one have to be sure that the horseshoe is completely dry before putting in the camera again.


QuoteOriginally posted by photogem Quote
Anyway, even Ricoh at times applied the sanding method but changed the solenoid for better latest in the K-70 (although I think it was already earlier on ).

The horseshoe/plunger has an anodised surface. If this surface is hurt, it can start to corrode.

I have shown this HERE and I have seen worse corrosion

on some sanded plungers.


But I also have seen sanded plungers which showed no sign of corrosion, nevertheless they failed again (those I saw, that's why they came into my house)
Sanding is a cheap option, no question, but it is not save!


The important question remains: As long as you can get the original "white made in Japan Solenoid", why invest all this work and then be "mean with ingredients"?
Doesn't make sense to me. Many had to do the repair again and in some cases due to further problems caused by this sanded solenoid the body was beyond repair.
In my case is because I have found a second hand cheap K30, and the only problem that it has is that it takes dark pictures. The owner (and I) doesn't know if this is due to the faulty solenoid or that the complete aperture system has to be changed, so at this moment I don't want to spend almost the same money the camera costs in a single solenoid. Also, it is going to be a second body in case my K50 fails (at this moment it is working properly, but it is likely to suffer from this problem), and I'll use it to train myself in opening and manipulating the camera, so I don't think it deserves the white solenoid (at least at this moment). If the main camera starts failing, the idea is to use it while I wait for a white solenoid for the K50.



QuoteOriginally posted by photogem Quote
Here a photo of a horseshoe with corrosion which failed again:



Even this method which an official Pentax repairplace applied failed again.

This was by the way the 2nd repair, the first was on warranty and failed as well. So this time they tried to decrease the surface by inscribing those notches:



A clever attempt I find and yet it failed again.
Clever because opposite to chamfering the plunger this way at least the contact with the sides of the plastic-housing does not change to the worse, i.e. becomes more wobbly which I explained in detail HERE in the Manual solenoid replacement Pentax K30 The green PET body anyway is far inferior to the PTFE body of the white Japan-Solenoid. This body acts as the bearing for the two plunger-shafts. They need to slide in and out with presicion. Chamfering the corners of the plunger lessens the surface on the side. The green PET body anyway has more tolerance than the white PTFE body.
That was another idea I had, reduce the contact area without touching the external surfaces that are in contact with the coils (I was thinking in a hole in each side, perpendicular to the contact area with the magnet and filled with glue or epoxy to avoid corrosion).
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