[jeallen01]

@photogem

I totally agree with your last comment "It is of zero interest here..... and I add: "time consuming ... endless babble"

[dem5867]

Yes, I do babble [A lot],, and a lot of times it's TMI and causes confusion.. I will try to keep things short !!!
Thanks for the feedback..

I feel like an and moron,, My K50 was broke for sometime and I was clueless about it !! 85 / 90 % of time I use the camera outdoors and there are only a few shots (That I didn't delete..) from outdoors appear to be darker then maybe they should be,, I just thought the camera took richer color pictures then my other cameras , personally I thought looked great, richer color.. yet I've been to a couple of functions were when I looked at the pictures I ended up deleting more pictures than I kept, not thinking thru I blamed it on operator error , not correcting for the back light coming thru the windows.. One of the sites I have shot many times under the same outdoor lighting coming thru the windows. Never even considered a problem with the camera.. Now that I remember I just want to get it out there that if like me you think you're having a back lighting issue , you may want to do the check on it to insure it's not the aperture problem.. I've owned enough cameras I should have catch it !!

[photogem]

The most important: Each thread has a title!
The title of this thread is "K-50 / K-500 Aperture Solenoid fix (DIY with pics)

For different questions or different problems there are different threads.

Or one opens a thread.

A thread like this is there to help people who are interested in a correct DIY approach.

And not to overload those who are interested.

[MarkJerling]

1. Now that it isn't as important ,, what do you all think this chances of getting a new or used K70 that has the aperture issues ??
2. If you purchased a K70 used and it didn't appear to have the problem , would you replaced the green solenoid as soon as you got the camera or would you wait until you have issues ??

Yikes! Wall of text. (No, I did not read it all - sorry!)

But to answer your questions:

1. There is a risk, but it would be a considerably lower risk than with the K-30 and K-50.

2. "Don't fix it if it ain't broke."

[dem5867]

MarkJerling; "Don't fix it if it ain't broke." I think you're right. I'm hoping to keep the K50 as a backup !!

Not that I'm looking to buy new , especially of here in the USA , so I'm asked if anybody knows if companies still do if you didn't by it in the US it's grey market and the warranty will not be valid in the US ?? If so are the Japanese new cameras grey market also ??

"There is a risk, but it would be a considerably lower risk than with the K-30 and K-50."

So am I hearing the there is a consensuses that the feeling is that the K70 definitely has less chance of having a solenoid issue ??

For me I kind of decided , I'm hoping to find a K70 with the aperture issue ,, yet If I see a used one that at the right price I'll pop for it.. It comes down to I've always loved my Pentaxs , I have years invested in Pentax lenses and accessories, the K70 has the features I want , I have parts and know how to do the repair, age
(My), so I think it's best to stay with the animals that I know..

What I was / am / will be worried about is that like me somebody don't know they have an issue.. I can't tell you how much of an idiot I feel like, I've been shooting for 40 years , I should have caught it years ago.. In my defense the early days it's was very intermittent, yet I have a wedding shoot that the church which was darker than the reception hall were the few pictures in the church came out good yet almost none of the hall came out at all, I should have noticed that !! Film day artifact I'm sure I don't look at the previews on the LCD screen , I most times wait till I download them to the PC weeks later, no competition like in my film days.. I need to make checking the previews a habit..

[MarkJerling]

Please start quoting correctly: Like this: (At the bottom of my post, you'll see there is a "quote" button, bottom right. Use that. (Or manually add the quote tags)

There is a risk, but it would be a considerably lower risk than with the K-30 and K-50.

"Don't fix it if it ain't broke."

But, to quote you:

So am I hearing the there is a consensuses that the feeling is that the K70 definitely has less chance of having a solenoid issue ??

Yes, so you're less likely to find a secondhand K-70 with the problem than a K-30 or K-50.

Not that I'm looking to buy new , especially of here in the USA , so I'm asked if anybody knows if companies still do if you didn't by it in the US it's grey market and the warranty will not be valid in the US ?? If so are the Japanese new cameras grey market also ??

As long as you buy from an authorised retailer in the USA, you'll not have issues with grey market goods and Pentax. Avoid unknown sellers on e-bay, amazon and the like. The way it works, if you buy a Pentax product new in another country, you generally have to return the product to that country for warranty service. Unless, the local agent will honour the warranty, which happens - sometimes.

[eltomek]

What is the original rootcause of the K-30/K-50 coil issue? I found this video

You Tube

You Tube

that suggests that the edges of the horseshoe needs to be filed, just as showed in the OP's post Fig 10. And the guys says it has fixed his camera - hoping then it's not needed to replace the electromagnet.

So what is happening to the original coil and why is K100's one better than K-30?

[MarkJerling]

What is the original rootcause of the K-30/K-50 coil issue? I found this video how to fix Pentax K50 and K30 with aperture problem - YouTube that suggests that the edges of the horseshoe needs to be filed, just as showed in the OP's post Fig 10. And the guys says it has fixed his camera - hoping then it's not needed to replace the electromagnet.

So what is happening to the original coil and why is K100's one better than K-30?

The root cause is the change from one manufacturer to another and one material to another. It's all explained here: A LITTLE BIT OF HISTORY: Development of the solenoid in Pentax cameras - PentaxForums.com
The filing solution is a temporary solution at best. The considered advice is to not use the filing method if you want a permanent fix. The filing method may cause other damage to your camera over time.

More information:
Manual solenoid replacement Pentax K30 / Discharge flash-condenser / Solenoid choice - PentaxForums.com
And:
Dark exposure problems on K-30 or K-50? Discussion Thread - PentaxForums.com
And:
Why you shouldn't file/sand the plunger of the green Chinasolenoid but replace it - PentaxForums.com

[nocturnal]

There is some evidence of metering issues - which have been misdiagnosed as aperture control issues (*). If you get different results depending on whether you use viewfinder or LV, that would be something to investigate. Can you use Exposure Compensation { +/- button } to bring results to within reasonable?

(*) One guy apparently gave up when he didn't get any help here - or from Pentax Repair {they replaced the aperture control unit, and announced it "fixed" .... but it still didn't work right}

You can discard all these misdiagnoses just by looking into the front of the lens and pressing the depth of field preview button, go through all the aperture settings on the camera and if the lens is closing down to the smallest f-stop with every f setting it is ABF or aperture block failure.

You don't even have to operate the shutter if you do the above.

[sherpataylor]

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.

I know this is an old post but still incredibly useful. I bought two new green solenoids on ebay for about £8 GB. Decided it was worth just replacing that one (as white ones unavailable) - rough statistics done by another forum estimated 5% failure rate so reasonable risk? Worth a try!
Just to update that parts from China are now available.

[reh321]

You can discard all these misdiagnoses just by looking into the front of the lens and pressing the depth of field preview button, go through all the aperture settings on the camera and if the lens is closing down to the smallest f-stop with every f setting it is ABF or aperture block failure.

You don't even have to operate the shutter if you do the above.

You are correct up to a point - my theory is that if you fix the solenoid so that your test will be passed - but there is still a problem with the resistor - the LCD will give good metering but the OVF still will not. That seems to be the lesson of several K-70 bodies recently sent in for repair which started off with bad OVF metering followed by bad metering from any source, and service replaced both the solenoid and the resistor.

[photogem]

You are correct up to a point - my theory is that if you fix the solenoid so that your test will be passed - but there is still a problem with the resistor - the LCD will give good metering but the OVF still will not. That seems to be the lesson of several K-70 bodies recently sent in for repair which started off with bad OVF metering followed by bad metering from any source, and service replaced both the solenoid and the resistor.

There is no resistor in the circuit!

It's a lot of gobbledygook, an invention to stop people to apply DIY.

I could also name it differently: Bu .... hit squared!

I don't mean you with this, but those who produce such nonsense.
But you should not just repeat something like this without having prove!


There is a resistor very close, but it isn't at all in the =PS circuit of the solenoid!
And this resistor will not fry if the solenoid is stuck.

[nocturnal]

There is no resistor in the circuit!

It's a lot of gobbledygook, an invention to stop people to apply DIY.

I could also name it differently: Bu .... hit squared!

I don't mean you with this, but those who produce such nonsense.
But you should not just repeat something like this without having prove!


There is a resistor very close, but it isn't at all in the =PS circuit of the solenoid!
And this resistor will not fry if the solenoid is stuck.

Resistors are generally the toughest electronic components and definitely won't fry in this case. Even large capacitors popping rarely blows resistors despite the varnish on them looking burnt etc.

As to the poster claiming white solenoids aren't available, not new but as explained you can salvage them from certain types of Pentax bodies. I have a broken *ist LD2 coming to me shortly with 2 of them inside assuming the seller hasn't removed them.

I got the solenoid on my K-30 working again for a short while by exercising the plunger a few times, initially it freed it up and it worked fine again for a short time but it didn't feel smooth. This is down to the space (wear) between the plunger and PET housing, not the electronics here and obviously the resistor was fine too even though apparently it's not even part of the aperture circuit 😁

[photogem]

I know this is an old post but still incredibly useful. I bought two new green solenoids on ebay for about £8 GB. Decided it was worth just replacing that one (as white ones unavailable) - rough statistics done by another forum estimated 5% failure rate so reasonable risk? Worth a try!
Just to update that parts from China are now available.

It might be useful first to study the according threads here instead of giving critical information.
I'm sure you mean it well but those China solenoids on ebay are worse than the original ones!

Those solenoids on ebay look like this one:


You can see very clearly: It is missing the 2 side posts which the Pentax-China-Solenoid does have:
https://www.pentaxforums.com/forums/members/85274-photogem/albums/13024-sole...ure122843.html

The coils are soldered to the same upright pins which are used for the lilac and pink wires. Not a good idea!
Plus they have a too strong holding force and do fail again.


If you know your car-engine did run with bad cheap oil, would you use the same oil again?

Even posing the question is kind of strange.


Those cheap ebay and other sourced Chinasolenoids kind of flood the markets since quite a while.

Cheapest rubbish.

[reh321]

There is no resistor in the circuit!

It's a lot of gobbledygook, an invention to stop people to apply DIY.

I could also name it differently: Bu .... hit squared!

I don't mean you with this, but those who produce such nonsense.
But you should not just repeat something like this without having prove!


There is a resistor very close, but it isn't at all in the =PS circuit of the solenoid!
And this resistor will not fry if the solenoid is stuck.

The "resistor" and other 'electronics" are the result of mention in servicing reports by professionals. I will continue to mention them until you explain exactly how metering can be correct for LCD - but bad for OVF - as a result of a bad solenoid.