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06-17-2018, 01:53 PM   #151
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I don't think there is a list generated anywhere. However if you can find a scrap 6mp camera, or even late SLR, I believe they all have white solenoids. Good luck hunting, they are out there.

06-19-2018, 02:27 AM   #152
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QuoteOriginally posted by lawsonstone Quote
Is it known which Pentax models have the white Japanese manufactured solenoid?
Yes:

K-50 - apreture failures? - Page 2 - PentaxForums.com

but I have also found green solenoids in


K100D, K110D, K100D Super, K200D

So the savest are the *ist Versions and all Samsung GX1 GX2's
06-19-2018, 12:08 PM   #153
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I've just pulled apart an SF7 but there was none to be found - unless it's buried deep inside.

Has anyone tried using a tape head demagnetizer?
06-19-2018, 12:13 PM   #154
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QuoteOriginally posted by altis Quote
Has anyone tried using a tape head demagnetizer?
I don't have the many aperture control issue threads memorized, but that was suggested, and rejected, somewhere, but feel free to try it yourself. Right now. there is no evidence that they problem is caused by magnetization, per se.

06-19-2018, 11:15 PM   #155
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QuoteOriginally posted by altis Quote
I've just pulled apart an SF7 but there was none to be found - unless it's buried deep inside.

Has anyone tried using a tape head demagnetizer?
Nobody has suggested that there would be a solenoid to be found in an SF7.


Tape-head demagnetizer is a very bad idea. It would de-magnetise everything including the magnet itself!

Best to study well and listen to people who have worked activly with solving this issue!


Study the threads well then you find the prober answer what the real problem is.

But to cut it short in a few words:

We have three issues:

1. A too strong magnet read my post #653

2. inferior surface of the horseshoe

3. inferior material (plastic) of the green solenoid body itself


Because the green solenoid has a too strong magnet, the friction on the horseshoe in the cheaper plastic-body is to strong and wears down.

The horseshoe gets stuck due to this wear.

This inferior surfaces create friction because the stronger magnet pulls the horseshoe with too much power.



Soldering or filing is not a good idea, after some time it will lead to the same failure and has often led to further damage.
The only solution is the white solenoid.
07-16-2018, 07:09 PM - 2 Likes   #156
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QuoteOriginally posted by madphys Quote
I hope this will be of help to those who are afraid to slightly take apart the camera, are not able to get their cameras serviced or the repair is too expensive. There are related bits of information scattered around the forums but I will try to put everything here - step by step - an easy to follow approach.

This can be applied to other cameras than K50/500 but the placement of screws can be a little bit different. In general it is the same for all models - you just have to be observant when looking for the screws.

So my approach uses an old but fully functional K100D (If you have an old camera gathering dust you can try a similar approach). I didn't want to ruin the K100 as it was in mint condition but after a long thought I figured out that I won't affect its functionality in any way. So the earlier models such as isD, K100D, K10D, K200D etc have a better quality solenoid part (it doesn't seem to fail in such large numbers) in them + they have 2 solenoids in them - other controls the flash compartment. Yes...this means less work to get the part.

Essential Tools required: Patience, 100g Vodka (HUMAN SR), Small but long screw-driver that fits the screw-heads - I suppose it is a JIS-type but you could get away with phillips, small soldering iron with rather pointy tip (low power - for electronics), tweezers (will help with the tiny screws and soldering).

PART I (Extraction from the donor_K100D).

To extract the solenoid we need to remove just the top cover

1) Press the open-flash button and don't close it. Take out the battery prior following operations.
2) If you didn't open the flash, then: Opening the flash...as it is electronic, we need to push the lock manually - for that we need something thin but rather stiff...something out of plastic works just fine. The lock is positioned on the side of the grip - so slide in the sheet of plastic inside the gap and wiggle - flash pops open.
3) Unscrewing screws -there are 8 screws to unscrew before it is possible to take off the top cover. 2 screws are hiding behind the rubber of the viewfinder (refer to Figure 1 of K500 as it is very similar) - pull the rubber part upwards to remove, next, 2 screws are in the flash compartment - that is why we opened it (Figure 2, green circles), 2 screws are each near the strap loops (Figure 2, purple circles - on K100 position is a bit different but you will find them), 1 screw is at the side of the flash compartment (Fig.3,b, purple circle)+ there is one final screw hiding in the battery compartment (Fig.4, green circle).

Figure 1


Figure 2


Figure 3


Figure 4


4) Now we can carefully take off the top cover. And what wee see - it is Fig 5.

Figure 5


5) The solenoid is held in place by one single screw - so we need to unscrew it...take notice - the contacts at the solenoid end are fixed with polymer - so it is hard to unsolder them - this is why I chose to unsolder at the board end and take out the solenoid with wires.

Figure 6


6) As can be seen in Fig 6, it is an easy task to unsolder the wires. Get your soldering iron up to the temperature and just touch the pads - if needed use tweezers and pull of the pink and purple wire. DO NOT heat the pad for prolonged time - if you didn't succeed, let it cool and try again a bit later. You don't want to overheat these pads.

Extraction completed!

Part II (getting to the green friend)

In theory you wouldn't need to remove the top cover of K50/K500 but as it is easier to change out the solenoid with wires - we will have to remove the top cover as well. Plus with loosened screws of the top cover it is easier to get off (and back in) the front cover.

1) Let's remove the bottom cover. Figure 4 - shows already removed bottom cover - take notice that some screws go inside metal and some inside plastic - so obviously threads on them are different - what I want to say - there are so many different screws in this camera - don't mess up. It is very advisable that you somehow take exact notice from which place you unscrewed a particular screw - make a sketch of the camera body if it helps or maybe you have a phenomenal memory.

So - Fig.4 purple circles are outer screws which are obvious. Blue circles show 2 screws which are underneath the battery compartment cover (so obviously you will need to open it). So Purple + Blue screws = bottom cover can be removed. Nice

2) Now the bottom cover has been removed but our goal is to remove the front cover - so underneath the bottom cover there is one more screw (green circle), which has to be unscrewed...and while we are here - undo the one inside the battery compartment (because we will need to remove the top cover as well)

4) The top cover goes the same as in the case of K100D - please refer to pictures. If you decide not to remove the top cover (somehow you have acquired fresh part and you want to solder the wires at the solenoid and not at the board), then still you need to undo screws inside flash compartment and one above RAW button (Fig.3). I would also advise to undo the top cover screw at the strap loop (Fig.2 - purple circle one the left) - it will hugely help to get the front cover back in more easily.

5) Final screws for the front cover...They are hiding beneath the rubber. (Fig 3 - green circles) - so on the right side there is one obvious screw and one underneath the rubber, but on the left side of the camera (right side of the image) - both are hidden from view. You need something sharp - I used my sharp tweezers to slightly rip of the corners (market with arrows) - the rubber sits on some sort of double sided tape, so it won't be too hard.

6) Now the screws have been undone (I really hope I didn't forget any) and it is time to remove the front cover. It sits tight. I suggest to start with the grip side - don't force it too much. But a slight force should be applied to get it off. The keyword is patience. Just to be safe - be careful with the flash capacitor (Fig.3 b shows its approximate position). If you have multimeter you can check the voltage across its terminals - If HOT..then discharge with ~10 KOhm resistor or just wait with the voltmeter attached.

7) Bingo...now we see our green friend (Figure 7). Again - you need to undo just one screw...I didn't drill any holes in the battery compartment and you don't need it either - a slight angle - when you use a long screw driver doesn't hurt. When you remove the solenoid be careful not to change position of the gear.

Figure 7


8) Unsoldering part - top cover has to be removed, because it is where the soldering pads are (Figure 8). Again be very careful - don't overheat - just touch with soldering iron and simultaneously remove the wires. BTW this is the part where HUMAN SR becomes handy. If something doesn't goes right - don't force it - let it cool and try again later.

Figure 8


9) Now let's look at both solenoids side by side (Figure 9)

Figure 9


As you can see - the dimensions are the same - color of wires is the same - so it is 1:1 replacement - both in K50/500 and K100D purple goes back to purple, pink goes back to pink.

10) So it is obvious that we put the better part from the K100D inside K50/500 where it will function as it should. When I checked the green friend I found that the magnetic attraction was really strong...the white friend could be taken appart considerably easier. So as I didn't want to limit functionality of my K100D, I decided to put the green friend back for opening the flash - as it is not such a crucial place (basically I have never used the built in flash). But before I did it - I used the "filing-trimming" method on the horse-shoe ends. You don't need to file a lot - just a bit (Fig. 10 shows my approach). After filing the force that hold it in place became considerably weaker...so I thought - good enough - and put it back in K100D, where it indeed works like intended.

Figure 10


So to put everything back you need to work in reverse order. Word of caution - when putting back the front cover - pay attention to the AF-switch...The equilibrium position is C.AF - move the switch on the cover in C.AF position and move the actual switch on the body also in its middle position - it will help to get the front cover on with the first time and not to take it off when you discover that something is wrong with the AF switch.

I hope this can help someone who is ready to try this operation. There is just no need to let a good camera loose some of its functionality.

UPDATE:

I did a bit of digging about solenoid part and I came up with some links for you. Still it is not that easy to buy just one single solenoid for a regular person, but - here is the info:
1) Part made in South Korea
2) Alibaba offering what I guess is the same as above
3) Summit electronics - this I think is already known
4) Maotech with some extended specifications

So I suppose these can be ordered just in large quantities. My guess is that for a regular person who doesn't have an old K100D or doesn't want to apply the "filing mod" (as it might not be a permanent fix, as reported by some people) the best thing is to hunt for a cheap (used) DVD or CD drive from laptop. I did a quick search and managed to find something as cheap as $5 on ebay. But - unfortunately these drives can utilize different solenoids so it is a lottery to some extent.
Thanks for the write-up madphys!

Both my wife's and my K-50 were broken and I was able to fix them with this.

Thanks Again!
08-08-2018, 12:02 PM   #157
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Oh man! Yes!! Thank you everybody!!

Fixed it!

I was so nervous that I thought I'd do sth stupid, since I am a total noob in soldering!!!

Thanx everybody for the tutorials and the thread and everything!!

My story is this..
Black pictures.
Then I tried to remove the solenoid to file the horseshoe... aaaaaand... I cut the wires byy mistake (shaky nervous hands)

Then after reading this tutorials, I even learned how to solder!!!

Many many Thanx!!!


Part 2... After soldering.. the mirror sometimes didn't go all the way down? Is there a possibility for this to happen, by screwing too tight the screw in the solenoid??
Problem is that I have only an old A lens, so I cannot try another lens.. But for sure this didn't happen before the soldering.. any ideas??

A walk-around I found is not to tighten the lens all the way. I mean right just when you are about to hear the click, you stop turning the lens.
This way, the mirror behave like it should.
Any ideas?


Last edited by le0n; 08-08-2018 at 12:09 PM.
08-09-2018, 02:00 AM   #158
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QuoteOriginally posted by le0n Quote
Oh man! Yes!! Thank you everybody!! Fixed it!
I was so nervous that I thought I'd do the stupid, since I am a total noob in soldering!!! .....

My story is this..
Black pictures.
Then I tried to remove the solenoid to file the horseshoe... aaaaaand... I cut the wires by mistake (shaky nervous hands)

Then after reading those tutorials, I even learned how to solder!!!
So you soldered the filed green solenoid back in? Soldered the broken wires? Where? New wires?
Or did you go the prober way, got a white solenoid and soldered that one in?

Anyway, the problems could stem from all this and it is not easy now to find out.


QuoteOriginally posted by le0n Quote
Part 2... After soldering.. the mirror sometimes didn't go all the way down? Is there a possibility for this to happen, by screwing too tight the screw in the solenoid??
No, the screw will not have an effect on the mirror

QuoteOriginally posted by le0n Quote
Problem is that I have only an old A lens, so I cannot try another lens.. But for sure this didn't happen before the soldering.. any ideas??

A walk-around I found is not to tighten the lens all the way. I mean right just when you are about to hear the click, you stop turning the lens.
This way, the mirror behave like it should.
Any ideas?
If that is the case I suspect the problem is with contacts and you might have forgotten to check that the AF mechanism and AF switch is alright (as you don't need it, it

might be jammed). This often happens because the inner part of the AF switch very easely moves into a different position when not connected with the switch itself on the the front cover!

So check: Can you move the AF switch into all 3 positions and does this small screwdrive part move when you change the position of the AF switch.

It is strange that the mirror would go all the way down when the lens is not tight screwed on but might not function proberly if the lens is tight fitting.
This makes me assume that somehow the whole frontpart does not sit properly. But this is guessing only.

Last edited by photogem; 08-09-2018 at 02:05 AM.
08-09-2018, 11:25 AM   #159
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QuoteOriginally posted by photogem Quote
So you soldered the filed green solenoid back in? Soldered the broken wires? Where? New wires?
Or did you go the prober way, got a white solenoid and soldered that one in?
As I was removing the old solenoid to do the filing thing, one of the wires got cut from its connection. So I soldered it back in the same solenoid..

The pink wire is the one that got disconnected/cut off/ripped from the solenoid (sorry for my english btw - not my native language)

QuoteOriginally posted by photogem Quote
No, the screw will not have an effect on the mirror
QuoteOriginally posted by photogem Quote
This often happens because the inner part of the AF switch very easely moves into a different position when not connected with the switch itself on the the front cover!

So check: Can you move the AF switch into all 3 positions and does this small screwdrive part move when you change the position of the AF switch.

Man you are a true genious!!! That was the problem! I didn't get the position right, so I disassembled the cover again and put it right this time! No problem now when taking pictures!

Thanx thanx thanx for all of your help!!!!

---------- Post added 08-09-2018 at 09:26 PM ----------

QuoteOriginally posted by photogem Quote
So you soldered the filed green solenoid back in? Soldered the broken wires? Where? New wires?
Or did you go the prober way, got a white solenoid and soldered that one in?
As I was removing the old solenoid to do the filing thing, one of the wires got cut from its connection. So I soldered it back in the same solenoid..

The pink wire is the one that got disconnected/cut off/ripped from the solenoid (sorry for my english btw - not my native language)

QuoteOriginally posted by photogem Quote
No, the screw will not have an effect on the mirror
QuoteOriginally posted by photogem Quote
This often happens because the inner part of the AF switch very easely moves into a different position when not connected with the switch itself on the the front cover!

So check: Can you move the AF switch into all 3 positions and does this small screwdrive part move when you change the position of the AF switch.

Man you are a true genious!!! That was the problem! I didn't get the position right, so I disassembled the cover again and put it right this time! No problem now when taking pictures!

Thanx thanx thanx for all of your help!!!!
08-09-2018, 11:20 PM   #160
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I see. You show a (my) picture of the Japanse made white solenoid to show which wire on your green solenoid got damaged.


I am sorry you didn't buy such a white solenoidand built it in!

Because it is much better in quality and lasts forever, old Pentax K10D's and K20D's prove it:


Some have shuttercounts of higher than 1 million in rare cases!

You see, if you go that road, the most difficult part is not really the work itself but the daring to do it. And as you described it, with your shaky hands this little accident happened and you damaged a wire. This led you to learn soldering and you did it.

This is what keeps some people off, they feel soldering is something they don't dare to do.


But actually unscrewing the green solenoid with the wires still fixed and then taking the horseshoe out, filing it and then installing the green solenoid back is more difficult than just to unsolder those two wires off those 2 pins on the solenoid.


One first unsolderes the wires from the green solenoid, then it is much easier to unscrew this green solenoid!
And then one has already done the first soldering on a solenoid!

As one now has easy access to those wires one can just "touch those one ends with the soldering tip" and add a little bit solder.


Thin leaded solder is the best, it flows better than lead-free solder.


There is even a very special solder available in the US called "wonder solder". This solder has a very low melting temperature and flows very very easely, is very easy to apply. Great product. Particular the very early (ancient) version with lead. Just make sure to have an open window and not to inhale those fumes, they are not healthy. But with an open window for such a tiny short soldering, no real danger! If you would have to work all day with solder, then one has to take real precautions, but not for such a tiny action!

One then screws the white solenoid into the Pentax and only then resolders those wires which are much easier to resolder due to their tips having had this tiny extra portion of solder.


And then yes, when assembling particular the front part, attention to this AF-switch. I had to realign it several times because it so easely moves to a different position.
This happens often.

So I am glad your problem is solved.


Now, as you know how to do this work, maybe think again about this white solenoid. Because if the filed green one goes bad again, usually there is more damage to the whole mechanism and the whole aperture block assembly has to be changed which is much more complicated. You have done the work. If you want your Pentax K30 to last forever, this is the way to go!
08-15-2018, 03:58 AM   #161
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Seems to be quite difficult to find cheap old * ist cameras etc, are there any specific examples of other devices that has the correct solenoid?

A list of where-found would be great, like "Old IBM thinkpad T20 cd-rom drive" etc.

I was just about to try the filing thing but that also seems to fail after a while..
08-16-2018, 01:03 AM   #162
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Solenoid used in cd-rom drives are useless and also made in China

QuoteOriginally posted by telum Quote
Seems to be quite difficult to find cheap old * ist cameras etc, are there any specific examples of other devices that has the correct solenoid?

A list of where-found would be great, like "Old IBM thinkpad T20 cd-rom drive" etc.

I was just about to try the filing thing but that also seems to fail after a while..
I have investigated a few cd-rom drive solenoids, all those are useless because:

1. Wrong impedance, all had 15 ohms! They work but due to half of the impedance the coils always see a much higher current and this will have eventually a damaging effect on several parts.

I built such a cd-rom solenoid once into an old K110D to see how it works. It "fired" more voilently, more snappy. A different sound when in action.

I didn't like the sound but I wanted to have a test camera. So I gave it to the daughter of a friend just as a surprise present, telling her, that
this repaired Pentax might get damaged again. She was thrilled and made many photos. But then it broke again, beyond repair!

Because the girl was now unhappy I had to get her another one, which was a K-m* (in USA K-2000) with a filed green solenoid. I should have known it, after a while dark pictures! Here I was more lucky and could built the white solenoid back in, it works well since!

I also tried those blue solenoids in the flash-circuits of a K-x, K100D and a K200D: No success at all, did not fire!


2. Made in China with all the negative construction issues often enough stated here in the forum!

I also was able to buy some NOS (New Old Stock) blue and green solenoids, for a short time those where available for very little money.
But it was a waste of money.... after testing I threw them away which I regret now, because it might have been a good idea to show photos, sorry about this!


*I chose the K110D and the K-m (K2000) for her because both have direct access to a few scene-modes, so a bit better than shooting automatic.
09-25-2018, 08:44 AM   #163
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I am starting to see dark frames on my K30, goes away after a few shots, I have not tried my AA adapter yet. I plan on shooting with the Li batteries until it no longer works. I installed the K50 firmware on my K30 (from a different post) several months ago and purchased a PLM 55-300 lens thinking my K30 might develop the aperture problem in the future and I didn't want to buy a lens that wouldn't work, it aperture seems to be starting to fail on all but the PLM lens. The PLM lens works with no problems. I am having problems finding the White solenoid so I can do the fix. Any other sources for the part???? Ebay shows only the Green Sol. Most of my shooting with the K30 is with the 55-300 PLM but I have other lenses I would like to use sometimes.

Last edited by hnikesch; 09-25-2018 at 11:06 AM.
10-10-2018, 05:47 AM   #164
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Hey everybody..
From my last post, where I filed the green solenoid thing, I managed to take about 1000 photos. Then again the black image reappeared... And something else as well. The mirror sometimes is not performing a full cycle, so it gets stuck midway after taking a picture.
Do you think this problem is related to the solenoid as well?
If so, do you think if I replace the solenoid with a new one, all problems should disappear (at least temporarily?) or if I replace the selonoid the shutter problem will remain and will have to replace another part?
Is it worth to service the camera or not? (Out of warranty)
Thank you
10-10-2018, 08:21 AM   #165
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The aperture, mirror and shutter movements are all interrelated. If one doesn't complete it's cycle the rest will get locked up too. So, yes, it is probably related. There could be something else failing in the diaphragm control block like the motor for the mirror or some of the gears are broken or slipping. There are also gears for the mirror that can break or slip.

Replacing the solenoid may or may not solve the problem. The only way to find out is to try.
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