[rlmartindale]

Thank you, I appreciate The info

FWIW....the repair done on my K-30 by the people at PC35, which apparently involved grinding, has worked well for over a year.

[photogem]

FWIW....the repair done on my K-30 by the people at PC35, which apparently involved grinding, has worked well for over a year.

Double posting! You already posted this in another thread! Why?

Anyway:

I'd advice this adress only in real emergency, the way how they grind the plunger is particularely bad
Check this thread for further details:
Solenoid problem return plus sound - PentaxForums.com

and carefully study:
Why you shouldn't file/sand the plunger of the green Chinasolenoid but replace it - PentaxForums.com

[rlmartindale]

I will certainly speak up if it fails....

[bobphoenix]

I picked up a k-30 from a charity auction site two days ago and last night I finally unboxed it.
This morning (when there was abundant light...) I started to fool around with it... The first thing I did was to reset all the settings and user options, format an SD card, then update the firmwear.
I also changed the "Aperture Ring" setting to enable, fitted an 18-55 DAL WR lens on it and took some pictures on auto...
They looked under exposed by an EV of -5 or Shutter speed double the correct exposure with lens stopped down to f22.

Now, I am still confused, because I've conducted the test from the beginning of this sticky thread, using an "F" lens with an "A" aperture, a Pentax "DAL" lens (setting the shutter speed and aperture in the camera) and a completely manual SMC lens (SMC 50mm 1.4) and the results are all over the place.

If I read the test instruction correctly... if I have the aperture block failure, the "A" lens will give me dark image in "A" mode, but near normal image with an aperture selected, (if all other settings are correct for the image.)

Then I did the same test with my manual 50mm... (I had no auto mode to compare)

Then I manually set up the camera with the crop sensor lens that is made for the K-30. (a DAL 18-55mm).

Here are the results (all images are marked with the lens and settings.

So, after looking at these images, my question is... am I dealing with the "aperture block failure" with this camera?






Correct exposure


Deliberately underexposed.




This is the settings the cameras computer told the camera to set the aperture, speed and ISO.

---

Last edited by bobphoenix; 03-07-2021 at 08:35 PM.

[photogem]

Thats how you test it and then know for sure:
Detection of aperture block/diaphragm-block failure/stuck solenoid K-30, K-50, K500 - PentaxForums.com

So the F-lens is ideal for it.

And then ... because it is most likely ABF:
Manual solenoid replacement Pentax K30 / Discharge flash-condenser / Solenoid choice - PentaxForums.com

[bobphoenix]

My confusion is, if the solenoid is "stuck" wouldn't it NOT move at all, or at worse stay in one position...
On shutter release, the aperture slide moves as expected... Albeit all the way to the top every time... (When I conduct the visual test on my K-7 there is no movement at all).

But, regardless, if the solenoid replacement is a fix for this problem in my K-30, I'll try it.

So, now, my next question is... can I cannibalize my old K20d (with a bad sensor) for this part...Or, should I just buy the part on-line?

Thanks
Bob

[jon.partsch]

My confusion is, if the solenoid is "stuck" wouldn't it NOT move at all, or at worse stay in one position...
On shutter release, the aperture slide moves as expected... Albeit all the way to the top every time... (When I conduct the visual test on my K-7 there is no movement at all).

But, regardless, if the solenoid replacement is a fix for this problem in my K-30, I'll try it.

So, now, my next question is... can I cannibalize my old K20d (with a bad sensor) for this part...Or, should I just buy the park on-line?

Thanks
Bob

Bob, my understanding is that the K20d uses a stepper motor for aperture control, so a different mechanism, and won't have the spare part you need.

I have a collection of "parts" bodies (*ist and K100 series) on the way, and I plan to harvest the "white, made in Japan" solenoids out of them and offer them here to the community for DIY repair of aperture block failure. I will do this at cost (probably about $25 each) as a service to forum members. Send me a PM or keep eye on marketplace if you are interested in one. I believe I should be able to harvest 7 of them, and I will keep one for myself just in case I need it, so I should have 6 to offer.

~ Jon

---------- Post added 04-14-2021 at 10:49 AM ----------

EDIT:
@bobphoenix , before photogem pops in here to sternly correct me, it does appear that your K20D has a solenoid you can harvest to repair a K-30 or K-50, based on the breakdown he provided here:

A LITTLE BIT OF HISTORY: Development of the solenoid in Pentax cameras - PentaxForums.com

[photogem]

My confusion is, if the solenoid is "stuck" wouldn't it NOT move at all, or at worse stay in one position...
On shutter release, the aperture slide moves as expected... Albeit all the way to the top every time... (When I conduct the visual test on my K-7 there is no movement at all).

But, regardless, if the solenoid replacement is a fix for this problem in my K-30, I'll try it.

So, now, my next question is... can I cannibalize my old K20d (with a bad sensor) for this part...Or, should I just buy the part on-line?

Usually the solenoid is stuck (i.e. no movement) all the time.
But in the beginning it it stuck the first shots, then gets free... but it gets worse until stuck all the time

The K20D has the correct solenoid, the K7 was the first with a stepper motor.

[Martin Stu]

But, regardless, if the solenoid replacement is a fix for this problem in my K-30, I'll try it.

my k-30 also had this problem... unfortunately I didn't have a Japanese solenoid... I disassembled the camera, in the solenoid the horseshoe seemed to jam, pulled it out of the coil and demagnetized... while everything works...it helped, but I just don't know for how long

[photogem]

my k-30 also had this problem... unfortunately I didn't have a Japanese solenoid... I disassembled the camera, in the solenoid the horseshoe seemed to jam, pulled it out of the coil and demagnetized... while everything works...it helped, but I just don't know for how long

Martin, I think its not a good idea to share this.
In almost all cases I know off this method led to failure in a very short time.
I have tried it in the beginning, I have a demagnetizer for tapemachine heads.

There is a blog in German just suggesting this method, it was full of commentaries writing that the problem occured again,
but most of the critical ones have been deleted (typical vanity problems of such bloggers), only 7 left.

And yet, the majority (3) warn or write about negative experiences,
a minority (2) had success and another minority (1) complain, the last minority (1) ask a question (which never got answered)

I see it like this:

1. If you invest the time/effort, then best to prepare well, i.e. get the solenoid and soldering iron and do it 100% right, because disassembling the body to do it your way is 95% of the work already!

2. Doing it your way and the 99% likelyhood that the problem will reoccur again means double work plus lose screws:
Most screws screw into plastic threads which each time get weaker!
Particular the solenoid screw itself is critical, because each actuation shakes the solenoid!
But a few other screws are critical as well. You then need to fill the bad threads with Epoxy, drill a 1mm hole into it and then hope it will hold.

But to explain it in further detail:
The plunger demagnetizes by itself when away from the body and this tiny permanent magnet!
This you can check with the tip of a screwdriver (demagnetized of course):
At the beginning the plunger "sticks" to it.
But if you wait a few seconds, it won't stick anymore.

But the main body which is made out of the same alloy as the plunger remains magnetised because it is always in contact with the magnet. So it won't lose its magnetic force. And that's one part of the problem which also explains why just swapping the plunger against one from a Japansolenoid won't help at all: Its the extra magnetic holding force of the magnet AND the main body!

I don't know if this alloy can change its magnetic properties! I don't think this is the case.
Because then high-shuttercount bodies should be more of a problem but the opposite is the case, regular constant use in general

helps to avoid or lessen ABF (some people claim to know more about it, usually those who either never saw the solenoid in real life or a few who dealt with it once or twice but right away became master-specialists, kind of similar to when you just got your driving-liscence and you think now you can start a driving-school)

[Martin Stu]

Martin, I think its not a good idea to share this.

of course I agree with you ... but, unfortunately, I had no other way out (what to do? there is no solenoid ... leave it as it is or try to do something? I decided to do something) .. The work done can be considered my own kind of training, and as a result, I'm no longer afraid to disassemble the camera, and in this, it seems to me, there is a positive side...

in time this work took no more than an hour ... to be honest, I had some doubts, I was afraid to break something, but if you take your time and do everything carefully, then it is not so difficult to disassemble and assemble ... but, perhaps many will prefer to turn to specialists in the workshop ... and so everyone can decide for themselves what to do...

[photogem]

of course I agree with you ... but, unfortunately, I had no other way out (what to do? there is no solenoid ... leave it as it is or try to do something? I decided to do something) .. The work done can be considered my own kind of training, and as a result, I'm no longer afraid to disassemble the camera, and in this, it seems to me, there is a positive side...

in time this work took no more than an hour ... to be honest, I had some doubts, I was afraid to break something, but if you take your time and do everything carefully, then it is not so difficult to disassemble and assemble ... but, perhaps many will prefer to turn to specialists in the workshop ... and so everyone can decide for themselves what to do...

No Martin, actually you don't agree with me!
You wrote about 8 month ago:

with this video you can try to heal your K-30...
How to fix Pentax K-50 (K-30) aperture - YouTube.
I also have a K-30 after watching this video I was able to fix this problem

Which means you applied sanding (see 12:10 on the video).
Sanding is not demagnetizing!


And you know well enough about sanding:
Why you shouldn't file/sand the plunger of the green Chinasolenoid but replace it - PentaxForums.com
But you recommend something different than what you actually applied yourself

[Martin Stu]

No Martin, actually you don't agree with me!

no, it is not so! how can you say what I think or don't think? here everyone shares their experience, I just shared my experience, which worked

[photogem]

no, it is not so! how can you say what I think or don't think? here everyone shares their experience, I just shared my experience, which worked

Martin:

1. July 12th. 2020 you recommend the method of this video which is about sanding and you wrote, that you followed that method.

2. Nine month later you write:

my k-30 also had this problem... unfortunately I didn't have a Japanese solenoid... I disassembled the camera, in the solenoid the horseshoe seemed to jam, pulled it out of the coil and demagnetized... while everything works...it helped, but I just don't know for how long

To me there seems to be a contradiction?

[Martin Stu]

if you want, it makes me wonder.

think about what? change the solenoid or try something else? everyone can choose for himself from the available possibilities