[martin42mm]

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Just a typo:
Aperture Solenoid Plunger Coupler For Pentax K-S1 K-30 K-50 K-500 Repair Part US | eBay
The they are worse: Older CD-ROM solenoids, most blue ones are 15ohms anyway.
The coils will draw more current and can damage the camera.


The only white one I know of (I purchase one longer time ago once from there) is this one:
Pentax K-30 K-50 K-70 K-S1/S2 K-500 Genuine White Solenoid Part - Japan - | eBay
The 2.nd photo shows the earlier different diaphragm-control-unit of an *istD-Series but mirrored with Photoshop or similar.

Thanks

[photogem]

I just received as well one of the latest official original Chinese-made green Pentax solenoids as it is used now in the K-70 and for repairs. So the same one as @martin42mm got from John Pye.

Because I got as well a load of those what I call "fake Pentax" made for Lenovo DVD-Roms solenoids my attention fell on a few differences which I have now added to the main article in the Solenoid History Thread

Have they changed the materials used or are they exactly the same?

I think they did. But the holding force is still stronger than the white Japan-solenoid, that is for sure.

That has now changed in the latest solenoid. The holding force is no longer too strong, if, then even a tiny bit less than the white Japan solenoid! And works well!

Do you know for certain if any of those failed repairs used the 'improved' solenoid that is now being used by Pentax for both K-70 and repairs?

They were repaired in 2019 and 2020, so I should think so.

So I have to adress this again:
Older repairs as I wrote in 2019 and 2020 yes. I don't know when Ricoh introduced the latest modification to the solenoid, the "dimple" in the plunger isn't the glue, it was there in the 1.st modification and is there in the latest 2.nd modification!

But: As soon as the latest solenoid was/is used, I daubt we will have failing repairs nor failing K-70's!

[martin42mm]

I just received as well one of the latest official original Chinese-made green Pentax solenoids as it is used now in the K-70 and for repairs. So the same one as @martin42mm got from John Pye.

Because I got as well a load of those what I call "fake Pentax" made for Lenovo DVD-Roms solenoids my attention fell on a few differences which I have now added to the main article in the Solenoid History Thread


That has now changed in the latest solenoid. The holding force is no longer too strong, if, then even a tiny bit less than the white Japan solenoid! And works well!



So I have to adress this again:
Older repairs as I wrote in 2019 and 2020 yes. I don't know when Ricoh introduced the latest modification to the solenoid, the "dimple" in the plunger isn't the glue, it was there in the 1.st modification and is there in the latest 2.nd modification!

But: As soon as the latest solenoid was/is used, I daubt we will have failing repairs nor failing K-70's!

Good to hear, and very reassuring. Thanks for the update.

[West Penn]

PM sent.

Anyway, there is another clever way how to solve this, have a look closely at this photo:

You can see they kind of cut/grated these lines into the bottom of the plunger.
This is the best solution modifiying the solenoid I have seen.
If you have access to somebody with a presicion drilling machine, then drill a 2mm diameter hole into both faces of the plunger and
fill them with epoxy. I did that once and it worked similar.

Photogem, regarding this method of fixing the solenoid problem, how deep would one need to drill the two ends of the horseshoe in order to ensure a long-lasting result? Also, what exactly does the epoxy add to this repair? Any other advice on trying this method?

I think I might try this method of repair if it would result in a long-term solution. I've misplaced the two Japanese-made solenoids that I got from a donor *ist D camera. I've just recently got a k100D that was sold as inoperable, but it seems to work fine so I'm not sure I want to disassemble it. I also got a K10D that has some sort of sensor issue -- a magenta zig-zag pattern on almost all images above ISO 100 -- but that only gives me one solenoid and I need to repair two cameras.

Thanks for all your insight on this issue.

[martin42mm]

Photogem, regarding this method of fixing the solenoid problem, how deep would one need to drill the two ends of the horseshoe in order to ensure a long-lasting result? Also, what exactly does the epoxy add to this repair? Any other advice on trying this method?

I think I might try this method of repair if it would result in a long-term solution. I've misplaced the two Japanese-made solenoids that I got from a donor *ist D camera. I've just recently got a k100D that was sold as inoperable, but it seems to work fine so I'm not sure I want to disassemble it. I also got a K10D that has some sort of sensor issue -- a magenta zig-zag pattern on almost all images above ISO 100 -- but that only gives me one solenoid and I need to repair two cameras.

Thanks for all your insight on this issue.

I'll let Photogem answer your more technical question, but regarding what you already have, you can simply remove the solenoid from the flash compartment of the K110d ( assuming it is a white one, of course!), put that in the solenoid section of whichever camera you want to do first, and then put the green one back in the K110d's flash compartment which will still leave you with a fully-working donor camera. As for the K10d, if that is teminally faulty, it makes more sense to use that as a donor since the white solenoid is a totally bullet-proof solution to the aperture issue.
It would be interesting, depending on Photogem's reply, to hear the longer-term reliability of any solenoid you do actaully modify, but since the current improved green solenoid is now available from Pentax for a very reasonable price, personally -unless I wanted to conduct an experiment which I am often tempted to do for the hell of it-I would go the white or improved green solenoid route for simplicity.

[West Penn]

Martin42mm, thanks for your input. My current thinking on this is that if the drilling and epoxy will solve the problem long term, that would be the easiest solution for me. If that's a no go, I'll likely take the white solenoid from the K10D as the sensor seems gone, but that still requires some further investigation. The CCD sensor gives a somewhat different look, so if it's still useable, I'd probably keep it around for some occasional use. I don't know for certain if the flash solenoid in the K100D is the white one, but that's also a possibility. Also, drilling means I won't have to waste a camera or two in the process of fixing my K50s.

[photogem]

Martin42mm, thanks for your input. My current thinking on this is that if the drilling and epoxy will solve the problem long term, that would be the easiest solution for me. If that's a no go, I'll likely take the white solenoid from the K10D as the sensor seems gone, but that still requires some further investigation. The CCD sensor gives a somewhat different look, so if it's still useable, I'd probably keep it around for some occasional use. I don't know for certain if the flash solenoid in the K100D is the white one, but that's also a possibility. Also, drilling means I won't have to waste a camera or two in the process of fixing my K50s.

Hello West Penn,
the thoughts of Martin42mm are on the point.
I only did the (2mm depth) drilling once and after a longer period the solenoid failed again.
The drilling demands a precision drill on a very good stand and the plunger has to be aligned very exactly, I have those tools and can do it
but most won't. And yet, not the very best solution.
The reason why epoxy is to stop the holes corroding, although I think corrosion only happens in regions near the sea, like I have seen it as well
with magnesium bodies like the K5II etc. Rare but it does happen.

The filed solenoids I had with corrosion came from bodies used near Hamburg and Kiel (both near or at the sea)


So:
1. Checking if there is a white Japan solenoid in your K100D flash is a good idea because the K100D will work 100% with the green Chinasolenoid there.
2. If the K10D is anyway damaged, repairing it's sensor is a waste of time.
Better to buy a low-shuttercount K10D or the K200D

The solenoid in the K10D is easy to get at and you can keep other parts of the K10D for spares.


So for sure I recommend to use the white solenoid, it is by far the very best solution.

[West Penn]

Photogem, thanks much for the response. Your insight into this problem is greatly appreciated by many.

I've got the equipment to do the drilling, so that's not a problem. But, since that process failed after a while when you tried it, I'm not going to waste my time on it. If only I could locate those two missing white solenoids that I harvested earlier.

[photogem]

Photogem, thanks much for the response. Your insight into this problem is greatly appreciated by many.

I've got the equipment to do the drilling, so that's not a problem. But, since that process failed after a while when you tried it, I'm not going to waste my time on it. If only I could locate those two missing white solenoids that I harvested earlier.

You're welcome.

I am always for good experiments but with a camera you mess up those plastic threads if you disassemble it too often. You want it to work and that's it.

Misplacing things happens.
With me it's my car/house-key, smartphone or purse. I find them again and every time I find them, I remember, ah....that's why I placed it there.

But those tiny solenoids, you probably had a very sensible place as well for them, too sensible maybe.

[martin42mm]

You're welcome.

I am always for good experiments but with a camera you mess up those plastic threads if you disassemble it too often. You want it to work and that's it.

Misplacing things happens.
With me it's my car/house-key, smartphone or purse. I find them again and every time I find them, I remember, ah....that's why I placed it there.

But those tiny solenoids, you probably had a very sensible place as well for them, too sensible maybe.

When the two new solenoids arrived from John Pye Technical, they clearly took no chances the solenoids would get lost in transit-the padded envelope that contained a small protective bubble-wrap inner envelope, then a further anti-static bag, was 35cm X 48cm! No chance they were going to get lost ....however the anti-static bag in now in a protective casing, in one of my many spares drawers...all I need to do now is remember which one.......
Happy Easter.

[slartibartfast01]

I finally recovered my K-50 which I left at a friend's house in 2019. The last photo was taken in September 2019 nearly 32 months ago. I tested it with trepidation and sure enough the first shot was dark, but subsequent shots have been fine. Fingers crossed I might have got away with it

[martin42mm]

I finally recovered my K-50 which I left at a friend's house in 2019. The last photo was taken in September 2019 nearly 32 months ago. I tested it with trepidation and sure enough the first shot was dark, but subsequent shots have been fine. Fingers crossed I might have got away with it

I had a similar issue with my K-S1 when left for a couple of months, but eventually it took dozens of attempts to get a correctly-exposed shot. Which is why I changed the solenoid for the 'upgraded' one.

[photogem]

I finally recovered my K-50 which I left at a friend's house in 2019. The last photo was taken in September 2019 nearly 32 months ago. I tested it with trepidation and sure enough the first shot was dark, but subsequent shots have been fine. Fingers crossed I might have got away with it

In most cases that is how it begins but if you now use it regularely it might go alright.
But if it continues, don't use "so called recommendations" i.e. series or similar to unblock the solenoid because in some cases this has led to disalignment behind it of the complex mechanism or the spring infront of the white toothed plastic wheel can get lose.

[slartibartfast01]

In most cases that is how it begins but if you now use it regularely it might go alright.
But if it continues, don't use "so called recommendations" i.e. series or similar to unblock the solenoid because in some cases this has led to disalignment behind it of the complex mechanism or the spring infront of the white toothed plastic wheel can get lose.

Tried again this morning and the first shot was dark again. I no longer have access to decent soldering equipment so this is going to be a total PITA

[martin42mm]

Tried again this morning and the first shot was dark again. I no longer have access to decent soldering equipment so this is going to be a total PITA

Good variable-heat miniature-bit soldering irons are not expensive, and work well. The repair is not a PITA, and there are only two wires to solder. My ( first ever) solenoid replacement in a K-50 a couple of weeks ago was 100% successful, and didn't take more than a couple of hours at a leisurely pace.