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04-08-2017, 01:32 PM   #511
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QuoteOriginally posted by enyaw Quote
some people really know their shit and I'm glad they are on this forum.
Im really glad too..we are here to help..

04-21-2017, 03:32 AM   #512
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QuoteOriginally posted by Jeff Lopez Quote
I have a K30 with is not affected (yet) with around 10k shutter counts.Im not a engineer but Ive done some small electronics as a hobby. Now, usually circuits like boards and sensors have very low current requirements, which a single battery will suffice to supply,but electromechanical assemblies such as solenoids and stepper motors work on a burst current and due to space, that type of high current burst would be supplied by a low voltage high capacity capacitator. If you add a bright lcd, a flash, a solenoid actuator,shutter,etc that would tax a small battery, youll need a good capacitator, this is basic high current electronics, like high wattage audio equipment.
This is a common misunderstanding. Watts are a factor and people have a totally wrong view about it!
Watts (in audio gear) are NOT power, far from it! The double of of 1 Watt is 10 Watts and the double of 10Watts is 100Watts. But you are right about current, which is Amperes (or here mA).

This basically means, that if your speakers have an efficiency of lets say 90dB (1W/1m) you need 10W so they can deliver 96dB and 100W so they can deliver 102dB), and vice versa speakers with 96dB efficience need only 1W to deliver this volume (SPL), a speaker with an efficiency of 102dBs (hornspeakers for example) only 0.1W.

Watts are secondary, if important at all!

QuoteOriginally posted by Jeff Lopez Quote
I think thats why most k30 issues can be temp fixed with AA batteries, as they supply more current than a camera battery. It is known that capacitators lose holding power as they get older and highly used.
Therefore, Im beginning to suspect that K30 caps are not holding a charge. Usually there are 2 caps inside a dslr, 1 for flash, 1 for electromechanical applications.
I don't think so because:

- after Pentax repairshops replaced K30/K50's with the original solenoid, the first ones already show the same problem

BUT

- repaired K30/K50s seem to still work. Mine does at least.


QuoteOriginally posted by Jeff Lopez Quote
While its true that changing the actuator for a new one works ok, eventually it will stop working due to bad caps..
Allthough cheap capacitors for example in powersupplys of TFT monitors and TVs etc. are a common problem, damage happens usually "all the sudden", you can source them easely because their top is bulged i.e. "puffed up". The other death of an electrolytic capacitor results by drying out (after many years of not being used)

Here you can see how blown capacitors look like: http://www.markdigital.com/wp-content/uploads/2011/02/bulging_capacitors.jpg

It is quite rare that they lose capacity, i.e. deliver less current!

After all, estimating the life-time of an electrolytic capacitor is quite complicated but well explained here on the basis if a high voltage capacitor
as used in tube-amplifiers:

http://jianghai-europe.com/wp-content/uploads/1-Jianghai-Europe-E-Cap-Lifeti...2012-10-30.pdf

---------- Post added 04-21-17 at 03:43 AM ----------

QuoteOriginally posted by Jeff Lopez Quote
Im am pretty sure its the caps..A metal solenoid which has no friction would never fail, unless its coil was shorted or open, and looking at such low voltages, that should never happen.If a solenoid coil is open or shorted, then the actuactor would never work, its a yes/no circuit. Now, if related control curcuits like caps are failing, then you will have erratic operations like yes/no/maybe...
This is the misconception: The green (made in China) solenoid has higher friction.
I have compared now 3 green solenoids with 8 white solenoids! It is more difficult to move the horseshoe out of the green solenoid.
I cannot (and will not) measure magnetic force, I don't need to! My sensitivity in my fingers is fine enough, I don't need more.
This is because I do and did a lot of fine presision work with my fingers, they are trained like the eye of a professional photographer which sees much more than the eye(s) of most people, we all now this quite well. This goes for all senses and explains why engineers working with their heads /brains) will never understand high quality audio where a "pair-of-good-ears" is needed. Trained ears can hear most suble differences which untrained ears will never hear. But those (brickhead) engineers will insist that their measurements are more precise than what well trained ears hear... which is.... well.... sheer bullshit.

So yes, you are quite right, a metal solenoid with no friction will not fail but this is the problem: Those green solenoids do have friction, they can even jam!

Last edited by photogem; 04-21-2017 at 03:44 AM.
04-21-2017, 07:30 AM   #513
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QuoteOriginally posted by photogem Quote
This is a common misunderstanding. Watts are a factor and people have a totally wrong view about it!
Watts (in audio gear) are NOT power, far from it!
Watts in audio are definitely power. You are talking about loudness.

04-21-2017, 09:09 AM   #514
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I still want to know how you know the green solenoids are made in China and the white ones are made in Japan. Is the country of origin marked on them? After all a company in Taiwan makes these solenoids with white plastic. And depending on who you talk to Taiwan is part of China. A company in Korea makes these solenoids too.

04-21-2017, 09:11 AM   #515
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QuoteOriginally posted by slartibartfast01 Quote
Watts in audio are definitely power. You are talking about loudness.
Sorry, but you are wrong with this. Watts are merely a factor.

A 1W single ended Triode amplifier can have immense power on a TAD hornspeaker combination or an Altec VOT.
It runs in its milli-watt region and delivers slamms... for which the "Great Slamm" by Wilson needs about 1000Watts.

Power is something very relative and cannot be measured in Watts (at all!)
04-21-2017, 09:19 AM   #516
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QuoteOriginally posted by photogem Quote
Sorry, but you are wrong with this. Watts are merely a factor.

A 1W single ended Triode amplifier can have immense power on a TAD hornspeaker combination or an Altec VOT.
It runs in its milli-watt region and delivers slamms... for which the "Great Slamm" by Wilson needs about 1000Watts.

Power is something very relative and cannot be measured in Watts (at all!)
A 1 Watt single ended triode amp can have immense loudness on a very efficient loudspeaker but it can never have immense power. Watts are a unit of Power. You seem to have chosen to define power as something else.

04-21-2017, 10:42 AM   #517
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The model MS-K01 solenoid manufactured by Summit Elec-Tech Co. Ltd. in Taiwan comes with white or black plastic. The rated holding force is 100gf minimum at 5.0VDC. FYI the rated operating voltage is 4.5 to 6.0 VDC and resistance is 200ohms +/-10% at 20°C. Summit Elec-Tech has been manufacturing and supplying solenoids since 1999 world-wide including Mainland China, Japan, Malaysia, and the US.

With your "finely tuned fingers" tell us how much (in gf or equivalent units) over or under this specification is for the white, a non-failed green and a failed solenoids. Have your fingers tell us how much friction adds (in gf or equivalent units) adds to this holding force.

After all a golfer with their "finely tuned eyes" can estimate the distance in feet their shot went with a high degree of accuracy which can be confirmed independently by measurement.


Last edited by Not a Number; 04-21-2017 at 10:56 AM.
04-21-2017, 04:16 PM   #518
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QuoteOriginally posted by photogem Quote
......
This is the misconception: The green (made in China) solenoid has higher friction.
I have compared now 3 green solenoids with 8 white solenoids! It is more difficult to move the horseshoe out of the green solenoid.
I cannot (and will not) measure magnetic force, I don't need to! My sensitivity in my fingers is fine enough, I don't need more.
This is because I do and did a lot of fine presision work with my fingers, they are trained like the eye of a professional photographer which sees much more than the eye(s) of most people, we all now this quite well. This goes for all senses and explains why engineers working with their heads /brains) will never understand high quality audio where a "pair-of-good-ears" is needed. Trained ears can hear most suble differences which untrained ears will never hear. But those (brickhead) engineers will insist that their measurements are more precise than what well trained ears hear... which is.... well.... sheer bullshit.

So yes, you are quite right, a metal solenoid with no friction will not fail but this is the problem: Those green solenoids do have friction, they can even jam!
The question which has never been answered to my satisfaction is very simple:
what is changing that causes a previously-working K-30/50 to become a no-longer-working camera??
and the related question is
what "mechanism" (*) causes this change?

(*) "mechanism" could mean corrosion, evaporation or other loss of lubrication, effect of magnetic force, etc.

04-22-2017, 01:59 AM - 1 Like   #519
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QuoteOriginally posted by reh321 Quote
The question which has never been answered to my satisfaction is very simple:
what is changing that causes a previously-working K-30/50 to become a no-longer-working camera??
and the related question is
what "mechanism" (*) causes this change?

(*) "mechanism" could mean corrosion, evaporation or other loss of lubrication, effect of magnetic force, etc.

Because we (me/myself) are kind of hobby researchers at the best not having advanced equipment handy to measure magnetic adhesive force which can be influenced by several factors.... we might not truly find out what causes this problem.

My guesses are:
1. inferior quality of the green solenoid, superior quality (machining, surface, material of the plastic which might even be PTFE)
2. difference in magnetic force: the magnet of the 3 green solenoids makes the horseshoe stick stronger inside the field-coil part. All 9 white solenoids I now have (3 from pre-digital japanese SLR cameras, 6 from DLSR bodys) need less force to pull out those horseshoes allthough the body is has less headroom, which might well be another cause because the horseshoe can slightly tilt when moving through the action of the fieldcoils which counteract/cancel the force of the magnet. This tilt can cause scratches in the green plastic. But I haven't taken the green solenoids apart (yet, who knows....).

So I leave this to those who so urgently need to know, they have to do their bit of work and make the effort to find out:

QuoteOriginally posted by Not a Number Quote
The model MS-K01 solenoid manufactured by Summit Elec-Tech Co. Ltd. in Taiwan comes with white or black plastic. The rated holding force is 100gf minimum at 5.0VDC. FYI the rated operating voltage is 4.5 to 6.0 VDC and resistance is 200ohms +/-10% at 20°C. Summit Elec-Tech has been manufacturing and supplying solenoids since 1999 world-wide including Mainland China, Japan, Malaysia, and the US.
And you have actually purchased the solenoid from Taiwan and therefore know for sure it actually is white or black?

Alibaba offers the black solenoid, but the picture shows a used solenoid with leftovers of that red laquer on the magnet itself.
Few weeks ago this photo showed exactly the same white solenoid which supposedly Summit offers as well.

Cd-rom Solenoid - Buy Solenoid Product on Alibaba.com

I was not able to find this solenoid on Summit's own website but only here:
Taiwan Magnet Solenoid from Linkou District Wholesaler: Summit Elec-Tech Co. Ltd

The photo on this webside obviously shows a used white solenoid: There are leftovers off this red laquer which was used to fix the screw holding the solenoid in place.

One person ordered the (white) solenoid from Alibaba, what arrived was "our dear beloved green friend".

QuoteOriginally posted by Not a Number Quote
With your "finely tuned fingers" tell us how much (in gf or equivalent units) over or under this specification is for the white, a non-failed green and a failed solenoids. Have your fingers tell us how much friction adds (in gf or equivalent units) adds to this holding force.
I am so sorry that I have to disappoint you here. You better consult a psychic or crystal (golf) ball:

QuoteOriginally posted by Not a Number Quote
After all a golfer with their "finely tuned eyes" can estimate the distance in feet their shot went with a high degree of accuracy which can be confirmed independently by measurement.
Actually, I can estimate very well the distance and speed of cars on the opposite lane when I need to overtake other cars on my lane (which is still possible in Germany), but I would not have a clue about the distance. Actually: I don't need to know.

For me it is enough to "sense" the difference. Well trained senses are much finer than any measurement equipment. Because they
are connected directly to something that is alive. Measuring is without question important. A friend of mine who never learned manual
photographing uses the K-S1 in various scene modes. She is excellent in "composing", a real artist. She is not interested in manual and I respect her approach. What counts after all is the result.

And that's what counts here as well: I just need to pull on the horseshoe of the solenoid and can sense very clear the difference between those two. More I don't need to know. Period!

Last edited by photogem; 04-22-2017 at 11:54 PM. Reason: Respecting enyaw's suggestion
04-22-2017, 02:38 PM - 1 Like   #520
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ok, we don't need to get personal here or overboard. We are all in this together. TOGETHER WE STAND DIVIDED WE FALL. Keep the ship on course please guys. This is an important issue.

thanks,
04-22-2017, 05:37 PM   #521
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QuoteOriginally posted by photogem Quote
Because we (me/myself) are kind of hobby researchers at the best not having advanced equipment handy to measure magnetic adhesive force which can be influenced by several factors.... we might not truly find out what causes this problem.

My guesses are:
1. inferior quality of the green solenoid, superior quality (machining, surface, material of the plastic which might even be PTFE)
2. difference in magnetic force: the magnet of the 3 green solenoids makes the horseshoe stick stronger inside the field-coil part. All 9 white solenoids I now have (3 from pre-digital japanese SLR cameras, 6 from DLSR bodys) need less force to pull out those horseshoes allthough the body is has less headroom, which might well be another cause because the horseshoe can slightly tilt when moving through the action of the fieldcoils which counteract/cancel the force of the magnet. This tilt can cause scratches in the green plastic. But I haven't taken the green solenoids apart (yet, who knows....).

So I leave this to those who so urgently need to know, they have to do their bit of work and make the effort to find out (which includes you as well of course!)
Actually, I have no urgent need to know. I asked my questions only because various people act as though this is a very simple problem, and I do not believe it is simple at all.
04-23-2017, 04:23 AM   #522
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QuoteOriginally posted by slartibartfast01 Quote
You can find an AA holder on Amazon for $6. If you had access to a variable DC power supply you could even wire it up to the battery holder and see how the solenoid behaves at different voltages.
I got my wife's K50 back about a week ago from the CA repairer. This is the 2nd repair. I'll post after a few months if still working, or sooner if it fails. Have to remember that AA's run low also.Even if I had a variable DC power supply, what could I do if it failed by a couple of tenths of a volt?
04-23-2017, 05:38 AM   #523
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QuoteOriginally posted by paolo11 Quote
I got my wife's K50 back about a week ago from the CA repairer. This is the 2nd repair. I'll post after a few months if still working, or sooner if it fails. Have to remember that AA's run low also.Even if I had a variable DC power supply, what could I do if it failed by a couple of tenths of a volt?
AA's can run very low very fast - and they are heavy compared to the D-Lion batteries. In life, but certainly not in weight, running this way reminds me of my Super Program and its button batteries.

I've been using them exclusively for a year now. I expect to hit the two-year and 2000 shutter count marks in another month or so; I'm curious to see how long I can use my regular lenses {I have a few old manual lenses packed in my K-30 bag}
04-23-2017, 06:11 AM   #524
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Reh321 - if it fails again, that's it. I'll use it exclusively as a manual camera. I noticed last time it failed I could use any lens in manual mode and it worked fine. I shoot most of the time in manual. It will be interesting how the K70 fares over time.
04-23-2017, 09:11 AM - 2 Likes   #525
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QuoteOriginally posted by mellowyeahlow Quote
how to fix Pentax K50 and K30 with aperture problem - YouTube

So I can confirm that this solution WORKS. It's not easy. But I just did it and it works.
But stupid me, I didn't save where the screws goes.
Can someone guide me to where the proper screws goes?

Or I'll just have to go one by one and just kind of guess.
I just repaired my Pentax succesfully today. To keep track of the screws I made a sheet:

I hope this will help you. The line with the circle is for the screw below the bottom plate
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