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02-21-2019, 04:45 AM   #226
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QuoteOriginally posted by photogem Quote
Rather than using this method, I'm going to assume a high voltage discharging rod will work. Would that be safe to assume?

02-21-2019, 05:51 AM   #227
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QuoteOriginally posted by sys3175 Quote
...... stating that the plunger gets magnetized (it doesn't)....
Just my 2 cents.
Any child learning a tiny bit of physics will know, that magnetic material gets magnetised.
Otherwise the plunger of our dear solenoids could not be held in place!


This picture shows a plunger I just pulled out of a white solenoid. Then I touched it with a screwdriver and surprise surprise,
the plunger does not fall of. And no, it's no magic, it's no glue.....
but I give you a clue:

It's magnetism!


I have no time to respond to all your other statements.
But just to make this sure:

I had sent copies of the original datasheet to moderators previously because when I make statements about its origin etc. those are statements about facts and not guesswork.

There is a reason why it is not going to be published but just to make this a final statement:

The company who manufactures the solenoid is a Japanese company and moved its plants to China.
The first time the green China-made solenoid was built into a Pentax was into the flashcircuit of the K100D.
The first time it was used in the aperture-circuit was with the introduction of the K-30.

The material of the white Japan made solenoid is PTFE and any person who has worked with this kind of PTFE can easely distinguish the difference between PTFE and the much cheaper PET (green solenoid body). I have worked with PTFE in the past for bearings. I have worked and developed precision electronics for over 40 years and I know what I speak about. I have soldered electronic parts with the help of the microscope, soldering a solenoid is kind of kindergarden compared to this.

All the rest is unimportant, I know very well what I speak and write about.
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Last edited by photogem; 02-23-2019 at 05:46 AM.
02-21-2019, 07:21 AM   #228
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Time to demagnetize your screwdriver, I'd say. This is no valid magnetization test, using two parts either of which may be magnetized, that's just ridiculous and if your expertise is on that level you should keep it to yourself.

Your other statements still aren't helpful without links or sources.

I've said what I've got to say and this is it for me, I won't fall for your bait and go your way endlessly repeating myself. So EOD here.

Last edited by sys3175; 02-21-2019 at 07:44 AM.
02-21-2019, 12:53 PM   #229
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Just FYI and to bring some content instead of conjecture, so that y'all can see for yourselves:

Shinmei Electric

There are no camera solenoids listed there, though. Datasheet doesn't mention type of plastic material. 20.000 actuations also is not a lot. A pause of 5secs between actuations is also not matching the Pentax part.

Company homepage:

Shinmei Electric

You can look at the history page (that our esteemed colleague has censored above) in its unblemished glory.

Shinmei Electric

So, why the secretiveness? It's all public. But there's no mention of camera solenoids, the ones in the list are destined to CD drive doors.

Now what we still don't know is if they made the part for Pentax, especially because this is not the only manufacturer of this kind of solenoid, what one could assume is that if they did, it was a tailor made part, made according to Pentax' wishes.
Or it's a red herring and someone else makes those parts.


Last edited by sys3175; 02-22-2019 at 01:58 AM.
02-21-2019, 04:43 PM   #230
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QuoteOriginally posted by sys3175 Quote
So, why the secretiveness? It's all public. But there's no mention of camera solenoids, the ones in the list are destined to CD drive doors.

Now what we still don't know is if they made the part for Pentax, especially because this is not the only manufacturer of this kind of solenoid, what one could assume is that if they did, it was a tailor made part, made according to Pentax' wishes.
Pentax doesn't commission parts like this. They use a generic part out of a catalog. In fact. that is part of the problem - the producer changed how they construct the part, apparently without telling Pentax or even changing the number; Pentax kept their same numbers, so they had no realization that anything had changed, nor do they have any way to trace back in their database. And, yes, users who do solenoid transplants sometimes go to old CD devices to get an appropriate solenoid.
02-21-2019, 07:10 PM   #231
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QuoteOriginally posted by sys3175 Quote
You can look at the history page (that our estimated colleague has censored above) in its unblemished glory.

Shinmei Electric
I see they moved the manufacturing to Taiwan in 1973. Which means the solenoids were made in Taiwan (China) as early as 1973, not Japan.

QuoteOriginally posted by reh321 Quote
Pentax doesn't commission parts like this. They use a generic part out of a catalog. In fact. that is part of the problem - the producer changed how they construct the part, apparently without telling Pentax or even changing the number; Pentax kept their same numbers, so they had no realization that anything had changed, nor do they have any way to trace back in their database. And, yes, users who do solenoid transplants sometimes go to old CD devices to get an appropriate solenoid.
From the product sheet:
1. The appearance and specifications of the products may be modified without prior notice to improve its performance.
2. This catalogue shows only outline specifications. When using the product, please obtain formal specifications.
3. Please see appendix [How to select solenoid].
4. Please confirm the performance on actual operation by simulation with actual environments for high reliability.
5. Please avoid the storage in dusty environment. If you store the products for a long time, do not keep open the
package.
6. Please take care for the usage in high humid atmosphere and design-in to meet the operating condition of the device,
for the coil resistance increases 0.4%/degree Celsius depending on the operating ambient temperature.
7. Please feel free to contact us for the models with other coil resistances.
02-22-2019, 05:54 AM   #232
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QuoteOriginally posted by Not a Number Quote
From the product sheet:
1. The appearance and specifications of the products may be modified without prior notice to improve its performance.
This is one of the problems in using a 'stock' part ..... their definition of "improve" may be different than yours ..... and I'm guessing Pentax got no notice at all of any changes to "appearances and specifications".
02-22-2019, 06:58 AM   #233
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QuoteOriginally posted by sys3175 Quote
Time to demagnetize your screwdriver, I'd say. This is no valid magnetization test, using two parts either of which may be magnetized, that's just ridiculous and if your expertise is on that level you should keep it to yourself.
Nonsense: If the plunger is made of material which can be magnetized ..... it will be attracted by a (yes, quite right..) magnetized tip of a screwdriver as well! That was the point!

But to bring that point closer to those really interested:

If you place the plunger of the green solenoid on a surface as well as the plunger of the white solenoid and you carefully move the tip of this very magnetized screwdriver (yes, you got that right, a magnetized tip of this very screwdriver!) then you can notice that you can come about 50% closer to the plunger of the white solenoid until it suddenly moves/clings to the screwdriver tip! Why? Very simply because the plunger of the green solenoid is magnetized more than the one of the white solenoid! So go figure!

QuoteOriginally posted by sys3175 Quote
Your other statements still aren't helpful without links or sources.
Ah... and you have brought how many links or sources to this theme? Zero!
My statements are not helpful for you because you are not interested. Like this magnetized plunger is stuck to the tip of the very magnetized tip of the screwdriver you are stuck to opposition for the sake of opposition. And no, I am not hijacking threads. I put straight such faults like for example faults in this post:

Because this person recommends solenoids from CD-Rom drives (which you did as well) and thus actually misleads others who don't know!

He mentions the different size of the magnet (giving them another holding-force) and he mentions a strange impedance of 15 ohms for the green K30 solenoid and 26 ohms for the CD Rom solenoid. Well, maybe this is due to the cheap (green) chinese multimeter he uses but I suspect he mixed up both values because the green K30 solenoid ALWAYS has 30 ohms!

But most Rom-solenoids 15 ohms. But in most cases they have this different holding force. And this is the very point. The wrong impedance and the different holding force can lead as much to further damage as does sanding the plunger of the green solenoid with I will proof with photos soon, the work is already done:

I have the whole aperture mechanism on my workbench and built the normal green solenoid, a green one with sanded plunger and the white Japan solenoid into it. The results are absolut clear as best clear spring water:

The plunger of the green solenoid not sanded tilts already quite clearly to the side!

More so the plunger of the sanded solenoid tilts

But the plunger of the white solenoid remains nice and straight!


QuoteOriginally posted by sys3175 Quote
I've said what I've got to say and this is it for me....
we shall see

QuoteOriginally posted by sys3175 Quote
I won't fall for your bait and go your way endlessly repeating myself. So EOD here.
There was never any discussion! There was just discursive arguing based on zero real investigation from your side.
Kind of "anti" for the sake of anti. But you falling for my bait.... c'mon, give us a break.... this is sandpit behaviour. Well, at least it matches the sanding-method.

So, to put this one straight as well, if you do some research, go the whole hog instead to remaining hooked in your anti-no-saying position:

QuoteOriginally posted by sys3175 Quote
There are no camera solenoids listed there
Good for the person who has eyes to read and investigates properly:
Of course Shinmei manufactures solenoids for cameras and the mentioned solenoid is the very one used in the Pentax K30 etc.

I have purchased exactly these solenoids (from Shinmei!) and they are exactly the ones built into the Pentax cameras since the K100D (flash)
and K30 (aperture circuit)! Period!

But of course they are useless for repair, as they will fail again and have proofed to fail.

I purchased them for research.

I never would dare to use it in a Pentax DSLR. Sanded or "as it is".

As said this is going to lead to further damage and I have the proof and will later on publish it here in this forum!

The only important thing is how to do this the best way and this is what I always stood for in this forum.

QuoteOriginally posted by reh321 Quote
This is one of the problems in using a 'stock' part ..... their definition of "improve" may be different than yours ..... and I'm guessing Pentax got no notice at all of any changes to "appearances and specifications".
Quite right! And this was the reason I did not want the papers to be made public, because it is food for those Pentax bashers and food for those greedy for sensationalism. Sys3175 had only his hunger for sensationalism in mind. There was zero though about why not to publish it. Just the urge to "be important".....
look... I found it.. and I bring it forward to you all..

It was my stupid fault, I gave him the bait without realising, well... he snapped pretty quickly.


QuoteOriginally posted by Not a Number Quote
I see they moved the manufacturing to Taiwan in 1973.
Which means the solenoids were made in Taiwan (China) as early as 1973, not Japan.
.... Solenoids made in Taiwan: Yes
the (Pentax) solenoid: NO


Last edited by photogem; 02-27-2019 at 02:54 AM. Reason: repair link
03-08-2019, 02:05 AM   #234
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QuoteOriginally posted by sys3175 Quote
The protection on the solder is really just a dot of felt marker paint, maybe to signal that the joint has been checked, you can just unsolder it.
Nonsense:
1. Solder protects itself
2. The paint is "threadlock paint"

Nobody wants to signal anything here .

QuoteOriginally posted by sys3175 Quote
The polarity is only a problem with parts ripped from other devices, it seems there are solenoids where the coil is wrapped the other way rotation-wise, it shouldn't be a problem with your part.
Again nonsense because you have never come across such solenoids with opposite polarity. Coils are maybe wrapped in box-spring mattresses ,
the coils of a solenoid are wound (with a winding-machine). Well.... I own one and I have wound coils, inductors and particular special transformers.

QuoteOriginally posted by sys3175 Quote
..it seems that most collateral damage occurs under the top plate of the camera where there are some sensitive ribbon connectors that are easy to screw up; I would recommend not removing the top, just loosening the screws a bit so that the other panels can be wiggled out.
Nonsense #3: The top part is attached as well with 2 longer screws behind the rubber eyecup . Just loosening those plus loosening the other screws and then wiggling panels will lead to damage of the plastic into which those 2 screws are screwed into. Because they will be bent upwards. But worse: One screw holding the top from underneath, i.e. inside the battery compartment: If you just loosen this one it will be pulled out further. Same for the 3 other screws holding the top part from the side! Epoxy Ahoy! But even worse, it will lead to:

QuoteOriginally posted by sys3175 Quote
Another common problem is that the AF switch gets misaligned during reassembly
because as you say, then you have to "wiggle out" the panels instead of gettin them out with ease because.... as I have recommended many times.. you
don't take the top part off completly but you lift it that bit prior taking all screws out completly (and never just loosening them) so that particular the front part can just be lifted instead of senseless wiggling and fiddling! This will give you also the needed access for removing and soldering the solenoid! If one would follow your advice there is not enough access to the solenoid, it sits too close to the top part and one could easely to more damage.
But also it will make the alignement of the AF-C-M switch much more difficult because you have to wiggle and fiddle and push to get the front part back in and

the alignement of this switch is then trial and error, which is to be avoided, because you can bend a part and then it is very difficult to get this back into proper alignement!


It is important to understand how the AF-C-M switch works:

It has an outer part which has to fit precisely to its inner part


The external has to be on AF (green), the inner part downwards.


One checks this prior reassembly:


Simply by watching the screwdrive rod of the screwdrive motor being in the correct position, i.e. it peeps out of that tiny hole of the k-mount right next to the AF/C/M switch.

Or the otherway round: External switch on M (the rod retreats) and the inner part upwards. Works as well of course. The inner part moves pretty easy so this is what has to be checked prior assembly. After putting the front part back on one checks that with moving the AF/C/M switch this rod moves in and out.


But now we come to your last wrong advice:

QuoteOriginally posted by sys3175 Quote
And be careful not to touch the contacts of the flash condensor (battery-like object on the side where there's no grip), it may be charged with high voltage
.
Nobody will touch the contacts of the flash condensor because both contacts are well protected!
One would have to poke inside this gap for this.

But there are contacts on the flash-circuit board and one can touch them pretty easy by mistake!


The shock could be that strong that one might drop the camera or,
if it is during soldering because one does hold the camera on that side, it is pretty possible that the hot tip of the soldeing iron will damage other parts because one moves in uncontrolled.

One has to give very clear instructions about when this high-voltage charged (and enough amperes to give a shock) electrolytic flash condensor is not charged, how to avoid charging and, if it is charged, how to discharge it!

I have done so several times and this is crucial

QuoteOriginally posted by sys3175 Quote
Don't be timid, it's less difficult than it seems.
Well, the only good advice if... and only if... nobody follows your other advices.

Last edited by photogem; 03-18-2019 at 03:10 PM.
03-10-2019, 11:18 AM   #235
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is it sure that this is exactly the same solenoid we need in k-50 cameras instead of the original green one?

MOATECH : COM


i could ask few tech people who might have some, because my k-50 is already beyond 55'000 shots and paying more than 40 bucks at ebay for it isn't too tempting. also i wouldn't risk to change the failed one for another green item, it can die just after few hundreds/thousands of shots again.
03-10-2019, 11:34 AM   #236
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QuoteOriginally posted by ignath Quote
is it sure that this is exactly the same solenoid we need in k-50 cameras instead of the original green one?

MOATECH : COM


i could ask few tech people who might have some, because my k-50 is already beyond 55'000 shots and paying more than 40 bucks at ebay for it isn't too tempting. also i wouldn't risk to change the failed one for another green item, it can die just after few hundreds/thousands of shots again.
I would say no. The resistance is too low. The correct one is 30 Ohms.

03-10-2019, 12:14 PM   #237
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QuoteOriginally posted by ignath Quote
is it sure that this is exactly the same solenoid we need in k-50 cameras instead of the original green one?

MOATECH : COM


i could ask few tech people who might have some, because my k-50 is already beyond 55'000 shots and paying more than 40 bucks at ebay for it isn't too tempting. also i wouldn't risk to change the failed one for another green item, it can die just after few hundreds/thousands of shots again.

By all means NO!

Only if you want to damage your K-50!
If you have a look at this photo you can see the Moatech solenoid is similar but not the same.

Last edited by photogem; 04-30-2019 at 09:22 AM.
03-10-2019, 12:30 PM   #238
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QuoteOriginally posted by slartibartfast01 Quote
I would say no. The resistance is too low. The correct one is 30 Ohms.
QuoteOriginally posted by photogem Quote
By all means NO!

Only if you want to damage your K-50!
!thank you for warning. this link was mentioned in the first post by author of this thread.

can anyone post a link to correct solenoid with exact tech specs?
03-10-2019, 02:39 PM   #239
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Here is the one I used:

Pentax K-30 K-50 K-S1/S2 K-500 Genuine Aperture Solenoid Plunger Part - Japan - | eBay
03-10-2019, 02:41 PM   #240
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QuoteOriginally posted by Navmaxlp Quote
Yes, they say they took these from genuine Pentax cameras.
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