[AldaCZ]

The Pentax K-70 is annouced - I'm curious whether it still has the same shakey aperture mechanism.

Not just you

[stevebrot]

Not just you

If you guys are concerned, the answer is simple. Wait two years before considering a K-70 purchase and then pick one up cheap.


Steve

[niceshot]

If you guys are concerned, the answer is simple. Wait two years before considering a K-70 purchase and then pick one up cheap.


Steve

You completely miss the point don't you? H e is concerned with another episode of failure, something you refuse to admit is going on.

[stevebrot]

You completely miss the point don't you? H e is concerned with another episode of failure, something you refuse to admit is going on.

No, I completely understand the point. He speculates that if the camera uses the same component that it might have the same problem. My response was to wait and see. In other words, if you are concerned about product weakness, it is best to not be an early adopter and only buy time-proven models*. One might also speculate that the K-70 uses mostly components from the K-3II including the more robust shutter/mirror/aperture controller from that camera with frame rate downgraded to 6 fps for marketing purposes. There is no evidence to support either assertion, but that is my point. If I were mocking, I would have suggested that we might also speculate that the K-70 is actually made by Monsanto using lubricating oils derived from GMOs...but I did not do that.

As for the assertion that I refuse to admit that there is an issue with the K-30/K50 aperture/mirror controller, you are badly mistaken. I was one of the first members of this site who assisted the initial wave of K-30 users who had this problem (2013), have closely monitored the issue since, and have been quick to suggest this particular failure when people submit K-30/K-50 troubleshooting requests. I also have personal experience with the failure with a close friend's K-50 (1 year post purchase with low shutter count) and have been through the warranty repair process here in the U.S.

I have a high degree of sympathy for those who purchased their cameras new and now find them out of warranty without having gotten much value from their investment. If they are within two months of warranty expiration, I usually suggest they contact Pentax to see if they will still fix their cameras. For those who believe that this failure is a universal problem afflicted all entry-level/consumer model Pentax cameras made since 2013, I suggest exploring whatever legal remedies might be available in your country of purchase.


Steve

* In Pentaxland, the best examples would be the K20D or K-7, both of which have virtually spotless defect histories and both of which have the same aperture control block design as the K-30/K-50.

---

Last edited by stevebrot; 06-12-2016 at 01:29 PM.

[niceshot]

No, I completely understand the point. He speculates that if the camera uses the same component that it might have the same problem. My response was to wait and see. In other words, if you are concerned about product weakness, it is best to not be an early adopter and only buy time-proven models*. One might also speculate that the K-70 uses mostly components from the K-3II including the more robust shutter/mirror/aperture controller from that camera with frame rate downgraded to 6 fps for marketing purposes. There is no evidence to support either assertion, but that is my point. If I were mocking, I would have suggested that we might also speculate that the K-70 is actually made by Monsanto using lubricating oils derived from GMOs...but I did not do that.

As for the assertion that I refuse to admit that there is an issue with the K-30/K50 aperture/mirror controller, you are badly mistaken. I was one of the first members of this site who assisted the initial wave of K-30 users who had this problem (2013), have closely monitored the issue since, and have been quick to suggest this particular failure when people submit K-30/K-50 troubleshooting requests. I also have personal experience with the failure with a close friend's K-50 (1 year post purchase with low shutter count) and have been through the warranty repair process here in the U.S.

I have a high degree of sympathy for those who purchased their cameras new and now find them out of warranty without having gotten much value from their investment. If they are within two months of warranty expiration, I usually suggest they contact Pentax to see if they will still fix their cameras. For those who believe that this failure is a universal problem afflicted all entry-level/consumer model Pentax cameras made since 2013, I suggest exploring whatever legal remedies might be available in your country of purchase.


Steve

* In Pentaxland, the best examples would be the K20D or K-7, both of which have virtually spotless defect histories and both of which have the same aperture control block design as the K-30/K-50.

ok Nice to see someone gets it, in my particular case it is the mirror motor. I know this cuz it doesn't respond to electric But it gets the 1.5 volts delivered to it. I will tear it down as soon as I have all the soldering supplies I need . They dont make it easy to replace the motor even though it is right there . S o I BELIEVE the problem is cheap motors

[AldaCZ]

ok Nice to see someone gets it, in my particular case it is the mirror motor. I know this cuz it doesn't respond to electric But it gets the 1.5 volts delivered to it. I will tear it down as soon as I have all the soldering supplies I need . They dont make it easy to replace the motor even though it is right there . S o I BELIEVE the problem is cheap motors

Thanks for insights!

If you figure it out Il"l try to fix my k30. In normal more it works in 99% of cases but When I get to LV I need to go bacc/in the LV sometimes for several times to get aperture open.

The fact the K70 doesn't have flash commander on main flash..even thought I plan to buy a wireless trigger., has really (sorry for languange) Pissed me off.

[niceshot]

Since I have a K-30, I am trying to collect more specific information about how this failure occurs, so I would be appreciative if you could answer the following two questions if you are able:

(1) roughly what was the shutter count when problems with your close friend's K-50 began?

(2) was your close friend's K-50 otherwise operable {i.e., is my tentative plan to use M42-mount lenses in case of that failure reasonable?

---------- Post added 06-13-16 at 11:53 PM ----------

So, strictly speaking, your's is not an aperture control failure?

wrong the motor is part of that equation.

[stevebrot]

(1) roughly what was the shutter count when problems with your close friend's K-50 began?

The camera was lightly used, but I have no idea regarding shutter count. Symptoms began at at just short of 12 months post-purchase.

(2) was your close friend's K-50 otherwise operable {i.e., is my tentative plan to use M42-mount lenses in case of that failure reasonable?

No. The aperture and mirror control sequences are closely coupled by both mechanical and electronic logic (same controller board). The aperture was flaky, which she did not notice, but it was when the mirror did not return fully "home" that the camera went in for repair. The mirror still worked, it just was poorly controlled. IIRC, Precision replaced both the mechanicals and the controller board.


Steve

[JoseFF]

I performed the "Russian" method on my K-30. No change in camera symptoms.
Any suggestions on what to do?... More than one of them (Russians) reported success, I wonder if I did anything wrong? I don´t think so ´cause it was a relatively easy procedure to follow. Or maybe I got wrong the sides of the horse shoe to file? IgorZ could you contact our Russian friends? Mayday, Mayday....

---------- Post added 06-15-16 at 03:17 PM ----------

Since I have a K-30, I am trying to collect more specific information about how this failure occurs, so I would be appreciative if you could answer the following two questions if you are able:

(1) roughly what was the shutter count when problems with your close friend's K-50 began?

(2) was your close friend's K-50 otherwise operable {i.e., is my tentative plan to use M42-mount lenses in case of that failure reasonable?

---------- Post added 06-13-16 at 11:53 PM ----------

So, strictly speaking, your's is not an aperture control failure?

Your answers reh321,
My K-30 started with 100% dark exposures at 7.000 shots. Since then it has been operable with manual lenses for around 1.000+ shots when I decided to stop using it and perform the Russian method to fix the problem before it would extend to the mirror motor. No success so far. The camera is still operable in manual mode.

[niceshot]

I performed the "Russian" method on my K-30. No change in camera symptoms.
Any suggestions on what to do?... More than one of them (Russians) reported success, I wonder if I did anything wrong? I don´t think so ´cause it was a relatively easy procedure to follow. Or maybe I got wrong the sides of the horse shoe to file? IgorZ could you contact our Russian friends? Mayday, Mayday....

---------- Post added 06-15-16 at 03:17 PM ----------


Your answers reh321,
My K-30 started with 100% dark exposures at 7.000 shots. Since then it has been operable with manual lenses for around 1.000+ shots when I decided to stop using it and perform the Russian method to fix the problem before it would extend to the mirror motor. No success so far. The camera is still operable in manual mode.

Listen I took the horse shoe magnet out of the coils and took off a significant amount off of the flat end . the what I noticed is that is has more magnetic drag then i reversed them and it has less drag. SO try reversing the horse shoe. I have no way to test this cuz my motor is shot. But take off some more material to reduce the magnetic drag and then pay attention to which way you put the horse shoe as to achieve the least amount of drag.

[IgorZ]

Listen I took the horse shoe magnet out of the coils and took off a significant amount off of the flat end . the what I noticed is that is has more magnetic drag then i reversed them and it has less drag. SO try reversing the horse shoe. I have no way to test this cuz my motor is shot. But take off some more material to reduce the magnetic drag and then pay attention to which way you put the horse shoe as to achieve the least amount of drag.

I will post on that list and see if they have a suggestion. I do remember though that one of them said not to flip the horse shoe. Not sure why...

[Nuno Almeida]

have you guys tried to demagnetize the horse shoe? Demagnetisers are common in metal tool shops, probably can do it for free, it would happen again though. I think the metal used on that piece should be resistant to being magnetised, and the problem may come from that, using the incorrect metal, or low level of quality control on the metallurgy side, just a not very informed opinion, I don't want to pretend to be a specialist on the matter

[nicolpa47]

The last posting raises an interesting point. I am interested in model railways. Many locomotives include cast mazak parts. These can sometimes suffer from "mazak rot" due to impurities in the metal mix. The rot was largely removed from UK produced models shortly after WW11 by improved factory procedures. Since production has been moved to China the rot has surfaced from time to time in particular models or batches. I know very little about production processes or from where camera manufacturers may source their parts, but it could explain why an apparently unchanged part may randomly fail - possibly depending upon the exact constitution of the metal part.

Colin

Added 18th June: I should also have said that the UK importers of the model products have so far mostly repaired, replaced, or offered alternative models, or offered financial compensation, even when the models are years out of warranty. This particularly when the problem has afflicted a large % of an item. Whether Pentax should do the same depends on the nature and extent of the problem. If it is a latent defect when the camera leaves the factory then, yes, they should stand behind their product for a prolonged period. Just my opinion.

[reh321]

The last posting raises an interesting point. I am interested in model railways. Many locomotives include cast mazak parts. These can sometimes suffer from "mazak rot" due to impurities in the metal mix. The rot was largely removed from UK produced models shortly after WW11 by improved factory procedures. Since production has been moved to China the rot has surfaced from time to time in particular models or batches. I know very little about production processes or from where camera manufacturers may source their parts, but it could explain why an apparently unchanged part may randomly fail - possibly depending upon the exact constitution of the metal part.

At one time in my career, I worked for an automotive company, developing software for a new receiving computer system. Most of my time was spent on the software that supported their inspection of incoming sub-assemblies. My personal belief is that Pentax had a failure in how they inspected this part - perhaps they didn't properly understand how it might fail, and therefore tested the wrong things. Hopefully this is in the past.

[JoseFF]

Lasts three posts make a lot of sense, They make me think of a probable solution to users with this problem: To replace the part. Does anybody in this forum know if it is possible to obtain the electromagnet from any supplier?