[sergiogonzalez]

Sergio, oh Sergio, it is not such a good idea to present us with those kind of fairytales!
You know, I admire real fairy-tales, such as 1001-night, Mulla Nasruddin, Till Ulenspiegel, but for their true content.
And thus, because this is today my 1001 post in this forum:
Sergio, no, I am not obsessed with the white Japan-Solenoid, far from it, I don't think obsession is anything that would come remotly close to it:
Obsession is an idee fixe, being stuck... and so... at least here we come to "in real life observed and measured facts"
.... we come to stuckness, but that one of a green coloured gremlin ... in this case a tiny solenoid whose plunger is stuck again and again.
So don't mix things up, it's the solenoid made in China which demands obsession by some.... maybe you are one of them? Your choice!

So again I have to sit down to correct your errors (as usual.... feels like 1001x times already done, well... I guess I have to learn something here,
maybe just 0+0=0, the famous Nuremberg Funnel is proven not to work?


I'd say if obsession comes into play then here and now by you turning everything (again) into fairytales:

If you cannot read this graph correctly then get some help but don't mislead the members of this forum!


Zero is zero, no daubt about that and so it is with your claim:

This claim = Zero = Wrong as wrong can be!

Because: Yes, the graph does start from zero but the graph goes not go up to 6V in any Cartesian system!

Or do you really want to make the reader believe there are only max. 6V DC existing in the world?


It always goes up to the chosen/desired setting the setting for each step is here clearly 2Volts and it is shown right there bottom left
1 = 2V so 2V per line!



Also it is very cleary to be seen:


Vpp = Volts from Peak to Peak are 8.32V (I don't know where you got those 8.2V from)

so a little spoonfeeding might help:
https://www.pentaxforums.com/forums/members/85274-photogem/albums/13035-whit...ture132123.jpg

The negative peak comes naturally from the the coils being unswitched!

Dear community.

I would like to share this last concept regarding the solenoids used in our Pentax equipment.

The graph with the static feature of 30 ohms that is that it equips our Ks2, K30 etc. supplied by the company Shinmei E. and that kindly provides us Photogem is very complete and allows quickly to evaluate the solenoid that we have in our hands and make a quick comparison with a specification made by the manufacturer.

As you will see I have added the values obtained in my post #47 and interpolated the intermediate values between 0 and 2.5 volt, which represents the behavior of the solenoid that equips my Pentax Ks2 (green)

You will quickly notice that my solenoid retains only 240 grf against 500 declared by the manufacturer, and releases the Plunguer with 30 grf of charge at 2.5 volt, against 3.5 volt declared by the manufacturer.

I have seen that even with these values my Pentax works well consistently.

This can serve as a tolerance curve for anyone who decides to evaluate the solenoid in this way.

Surely the factory has these tolerance curves.

As for the value of 8.32 volt found by Fotogem in the previous post, I think you should take it carefully.

Measuring with the oscilloscope with the solenoid connected and mounted on the camera can lead to erroneous conclusions if you do not know precisely the interaction between the systems that are interconnected, as there are dynamic phenomena that produce induced shocks and reverse tensions on the same solenoid and in the electronic circuits that completely distort the conclusions.

As you will see if in the static test proposed by the diagram, applied a voltage of 8.32 volt, the magnetic field produced by the coils would not only nullify the field of the magnet, but would overcome it, not letting the Plunger take off from its armor.

This does not happen as Photogem declares.

That is why the manufacturer statically analyzes the solenoid in a range of 0 to 6 volt and 0 to 500 grf, which is the area of interest that represents the operation of the solenoid mounted on the camera.

The research of the measurement with the oscilloscope is interesting, but we would need to have the flowchart to identify the essential events of the camera's synchronism and use at least two simultaneous measurement channels to analyze events in different components of the camera.
Surely the highly specialized repair laboratories have comparison cards of the waves obtained that allow to diagnose quickly and surely the problems that may arise.

Hoping to collaborate
Best regards

Attached Images

 

[sergiogonzalez]

I have a ks2 that works fine. I have developed a tick that is happening more often. I get a double mirror flip. Tonight i took 27 images and probably about 5 times the mirror flipped twice. I had thought for some time i was getting 2 images but it is just the mirror.
I wonder if this is somewhat common and if it is, if it happens instead, or as frequently as ABF or with ABF, or if I am a one off. I could see if this behavior was put toward the AB, an inferior solenoid might fail where a better one would not. Just a thought.

Sorry for the delay Swanlefitte.
If you can clarify that it is ABF?
Thank you!

[swanlefitte]

Sorry for the delay Swanlefitte.
If you can clarify that it is ABF?
Thank you!

My ks-2 doesn't take dark exposures. It flips the mirror twice. One press in single frame mode sometimes raises the mirror twice. It sounds like it is shooting in continuous frame mode but only shooting one frame. I wondered if the gear and brush could fail somehow causing this behavior perhaps by losing contact somewhere in the cycle.

[sergiogonzalez]

My ks-2 doesn't take dark exposures. It flips the mirror twice. One press in single frame mode sometimes raises the mirror twice. It sounds like it is shooting in continuous frame mode but only shooting one frame. I wondered if the gear and brush could fail somehow causing this behavior perhaps by losing contact somewhere in the cycle.

Dear Swanlefitte
It's a rare fault.
How does the camera behave in Live view mode?
Remember that in this mode the camera works in a raised mirror.
When the camera shooting, lower the mirror, measure, lift the mirror taking the exposure, lower it again, and then lift it up to continue in Live View mode.
If you see that the camera add one more mirror move, then there's a problem.

Another test you can do is turn Live View on and then turn it off to switch to normal mode before taking a photo. Then take the picture. He's doing this for a few days.
This will make the mechanisms and contacts preheat a little the old lubrication they have and re-run.

If the camera does not fail to do this practice, then you may think that the diaphragm control and/or curtain control may need maintenance.

So you describe, in the first lift of the mirror, the sensor does not receive the order to record the image.
You would have to get a flowchart where you can determine where the recording order passes and review the electronic stage that participates.

That's what I can think of from a distance.

Greetings

---

Last edited by sergiogonzalez; 09-01-2020 at 04:11 PM. Reason: mistake

[swanlefitte]

Thanks,
I was thinking that you might see a connection to the gear and brushes from your research. If there was it could lead to more understanding. It is an annoying occurrence which has no real effect, at least yet. I rarely use liveview. When I do it is to set up a shot. I only need 1 picture to get what I want. I will look for it if I use it. As it is I notice if I take a picture of a squirrel and take 10 pictures in a minute I get the extra flap once. On a bad day it happens less than 20%, on a good day it doesn't happen. I should take humidity, temp, and other readings to see if I can find a common denominator.

[sergiogonzalez]

Thanks,
I was thinking that you might see a connection to the gear and brushes from your research. If there was it could lead to more understanding. It is an annoying occurrence which has no real effect, at least yet. I rarely use liveview. When I do it is to set up a shot. I only need 1 picture to get what I want. I will look for it if I use it. As it is I notice if I take a picture of a squirrel and take 10 pictures in a minute I get the extra flap once. On a bad day it happens less than 20%, on a good day it doesn't happen. I should take humidity, temp, and other readings to see if I can find a common denominator.

Yes Swanlefitte.

From what you describe, it's a good decision to live with the problem if the shots are good.

In addition to how failures happen, it assumes that it is a problem of false contacts.

The only critical contacts that exist are the diaphragm control switch (which controls the movement of the mirror) and a switch mounted on the curtain control, which sends the flash timing signal, and can probably have an influence on the image recording signal.
When the time comes you have to think about doing lubrication and cleaning maintenance and surely your camera will be reborn.
My camera's really good. It's consistent to function like it was new.
Strong hug

[solatana]

my Pentax not KS2 but K70 but is very similar to KS2.
it develop darkpicture problem. repair with K30 was very simple. with K70 some more difficult but can manage.
I have Fluke meter which give very good reading

7,122volt it is measure on solenoid himself.

before solenoid come diode and solenoid integrated circuit.

Attached Images

 

[sergiogonzalez]

my Pentax not KS2 but K70 but is very similar to KS2.
it develop darkpicture problem. repair with K30 was very simple. with K70 some more difficult but can manage.
I have Fluke meter which give very good reading

7,122volt it is measure on solenoid himself.

before solenoid come diode and solenoid integrated circuit.

Dear Solatana.
You should carefully read the post #47 and #91, which will allow you to evaluate only the solenoid.
If you find values similar to those of the manufacturer's curves and the curve I found in my KS2, the solenoid is in good condition.
If the solenoid is in good condition after testing outside the camera, but you have dark photos, the fact that you measured a peak voltage of 7.12 volt is not enough for it to work, as that voltage peak does not last long enough for the solenoid to act efficiently.
In this case you have to intervene the diaphragm control switch that surely does not make good contact.
All this is developed in detail in this block.
I hope it helps.
Best regards

[solatana]

but solenoid not in contact with switch.

solenoid only in contact with solenoiddriver and diode for protecting:
https://www.pentaxforums.com/forums/attachments/189-repairs-warranty-service...r-aufsicht.jpg

solenoid get impuls from this one driver and have not any connection to gliding switch you say having 3 fingers

[sergiogonzalez]

but solenoid not in contact with switch.

solenoid only in contact with solenoiddriver and diode for protecting:
https://www.pentaxforums.com/forums/attachments/189-repairs-warranty-service...r-aufsicht.jpg

solenoid get impuls from this one driver and have not any connection to gliding switch you say having 3 fingers

Yes, you're right, the solenoid is commanded by electronic elements, but the switch enables the negative pole that electronic components receive at different times that build the trigger logic.

If this negative signal is not clear and noise-free, the energy received by the solenoid may be insufficient and is the cause of the dark photos, as the anchors, that selected the diaphragm aperture determined by the processor will not arrive in time and the diaphragm will close to the maximum.

It is important to understand the idea of energy received by the solenoid. That is why the differences found between analyzing the solenoid with an energy produced by direct current (case of the graph explained) and the energy it receives through a pulse in the camera that does not reach 10 msec. (this is the time that the diaphragm control switch makes contact at the time of shooting)

Finally the areas under the curve must be the same and must trigger the solenoid.

It is for all this (quite complex and difficult to understand and explain) that a white solenoid, which is surely of better quality, will also fail if the diaphragm control switch is not in perfect condition.

The white solenoid is surely activated with less energy than green, which is why the cameras will run a while longer, but when the wear, dirty or damage of the brushes of the diaphragm switch no longer send that minimum signal, the fault will appear inexorably.

Thank you for your interest.
Best regards

[swanlefitte]

It is for all this (quite complex and difficult to understand and explain) that a white solenoid, which is surely of better quality, will also fail if the diaphragm control switch is not in perfect condition.

The white solenoid is surely activated with less energy than green, which is why the cameras will run a while longer, but when the wear, dirty or damage of the brushes of the diaphragm switch no longer send that minimum signal, the fault will appear inexorably.

Thank you for your interest.
Best regards

This is hypothesis that so far has no evidence. I hope you are wrong because it affects many repairs.

[sergiogonzalez]

Thanks,
I was thinking that you might see a connection to the gear and brushes from your research. If there was it could lead to more understanding. It is an annoying occurrence which has no real effect, at least yet. I rarely use liveview. When I do it is to set up a shot. I only need 1 picture to get what I want. I will look for it if I use it. As it is I notice if I take a picture of a squirrel and take 10 pictures in a minute I get the extra flap once. On a bad day it happens less than 20%, on a good day it doesn't happen. I should take humidity, temp, and other readings to see if I can find a common denominator.

Dear Swanlefitte:
I've been left thinking about the flaw in your KS2, and I think you should check the off/on/video selector brushes, which work concentrically with the shutter switch. These brushes have a direct influence on the logic of photography mode.
Getting to these brushes is not complicated at all and you don't need to keep skinning any wires.
Any of the threads photogem has written will help you get to the brushes of this switch smoothly.
Check that the brushes are aligned, have coherent radio, are on the same plane so that they discharge the same pressure at any angle, and essentially that they are clean.
Once the physical condition has been checked, check the rubbing surface of the same on the contact plate. After carefully cleaning everything with isopropyl alcohol, proceed to lubricate the contact plate with some good lubricant cleans good quality contacts.
Another element that may be interfering is the same shutter switch, which gives two effects, the half-race and the race background that shoots the photo. Perhaps this switch, presents some crack in your contact saucers that may be interfering. If you could inspect it and try it off the equipment it would be good, but here you would need to have a lot of experience.
I hope that with the cleaning of the brushes it reaches. Also try adding a drop of clean contacts to the shutter switch.

Good luck.

A big hug.

[photogem]

And again S.G. never answers the real questions posed to him, he just evades.
Why?
Simply because S.G. never ever had a Japan Solenoid in his hands.
He has no right to make any assumptions about it.

Those contact bushes which are similar since the earliest SLR MZ Bodies with similar (but not same) solenoids.
Other switches of some Pentax bodies do fail every time but it is very rare, in no relation to the failure-rates we have with the green China solenoid.

The most failures with had with the non-WR Pentax K-x and its e-dial:
Tutorial E-Dial (Thumbwheel) Repair Pentax K-x K-m (2000) and K-r - PentaxForums.com

It happens because this dial is not well protected at all, dirt/grease/fat etc. can enter very easely.

The other dials and switches rarely fail.

I have repaired many Pentax bodies with solenoid failure and I have instructed many doing so:
I never came across any problems with this hidden switch S.G. so much wants to be the culprit.
And I have studied it well with a K30.
Except of the standard "mains negative" there is no conduction ever from this switch to the circuit which fires the solenoid
but only indirect to the microprocessor.


But lets suppose there would be a direct relation:
Why then does the Japan Solenoid never ever fail?


So to put it into other words:

As Heinrich Hertz and Ludwig Boltzmann argued (following an earlier proof by Leibnitz, Maupertius, Klein und Hankel in pure theory):

Any equation that is to have any empirical application ("outcome with result") has to yield a result other than zero (0).

His "Switch/brushes + the green solenoid must function because Ricoh engineers would otherwise not use it" = zero (0).

It has no empirical value. It is of no help even if it would be right (which it isn't)

[sergiogonzalez]

Except of the standard "mains negative" there is no conduction ever from this switch to the circuit which fires the solenoid
but only indirect to the microprocessor.

I think you're starting to understand the problem.
If you have a good negative reference, which is given by the diaphragm control switch, you will no longer have a problem with the solenoid.
My Pentax is doing very well with green, more than 5 months ago.
Thank you Photogem for all the information you provide us, which gives good orderly results.
Strong hug.

[photogem]

I think you're starting to understand the problem.

amazing news after todays news! Wow

If you have a good negative reference, which is given by the diaphragm control switch, you will no longer have a problem with the solenoid.

The minus/negative is in 99% strong, it isn't affected by the switch at all

My Pentax is doing very well with green, more than 5 months ago.

But not because you cleaned the s-witch!

Thank you Photogem for all the information you provide us, which gives good orderly results.
Strong hug.

I think you need this hug from somebody else, much closer to you