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01-22-2018, 02:54 AM   #76
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QuoteOriginally posted by Rob-48 Quote
Current shutter count of my GOOD, (white), K-50 is only 1,534
Date of manufacture 2015-12-04
could you give a Serialnumber for this one as well.
Or the first 2 or 4 numbers?

That would be very helpful.

This is the first time Ricoh actually indirectly admits the problem and admits a change of the Solenoid!

01-22-2018, 09:04 AM - 1 Like   #77
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K-50

Current shutter count of my GOOD, (white), K-50 is only 1,534
Date of manufacture 2015-12-04
Serial # 6280896

Read more at: Dark exposure problems on K-30 or K-50? Read me first! - Page 6 - PentaxForums.com
01-29-2018, 07:24 PM   #78
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QuoteOriginally posted by caliscouser Quote
OK that is the guy in California who doesn't say what his repair technique is. We can only assume it is filing down horseshoe or something like that.

The only real long term fix for this problem is to replace the solenoid with a high quality 'white' one. Anything else is a band-aid in my opinion.
Since that person's main business seems to be selling used parts from cameras including Pentax DSLRs it is just as reasonable to conclude the repair he makes is to replace the solenoid with those taken from other Pentax bodies.
01-29-2018, 08:49 PM   #79
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My Pentax k-50 has 3,403 shutter activations.

Date of Birth: 1/20/2016.

Serial Number: 6096174.

Tonytee

01-29-2018, 08:50 PM   #80
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QuoteOriginally posted by Not a Number Quote
Since that person's main business seems to be selling used parts from cameras including Pentax DSLRs it is just as reasonable to conclude the repair he makes is to replace the solenoid with those taken from other Pentax bodies
No I don't think so. A few people on here have reported that the repair from this vendor has failed after a few months.

Plus their own website states "This repair includes a modification of the aperture control block", a 'modification'. Later they state they don't do a 'replacement' like Pentax official repair as they believe it will fail again.
02-02-2018, 03:05 AM   #81
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k-50 'failure'

QuoteOriginally posted by Tonytee Quote
My Pentax k-50 has 3,403 shutter activations.

Date of Birth: 1/20/2016.

Serial Number: 6096174.

Tonytee
My research suggests that the failure is a function of 'age', rather than of 'number of photos'
02-03-2018, 03:05 AM   #82
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QuoteOriginally posted by caliscouser Quote
QuoteOriginally posted by Not a Number Quote
Since that (Californian) person's main business seems to be selling used parts from cameras including Pentax DSLRs it is just as reasonable to conclude the repair he makes is to replace the solenoid with those taken from other Pentax bodies.
No I don't think so. A few people on here have reported that the repair from this vendor has failed after a few months.
It is a shame that we cannot peep into one of those Pentaxes he repaired


QuoteOriginally posted by caliscouser Quote
Plus their own website states "This repair includes a modification of the aperture control block", a 'modification'. Later they state they don't do a 'replacement' like Pentax official repair as they believe it will fail again.
Sounds very strongly that he either files the horseshoe or he uses the soldering method.

---------- Post added 02-03-18 at 03:30 AM ----------

QuoteOriginally posted by Rob-48 Quote
QuoteOriginally posted by Tonytee Quote
My Pentax k-50 has 3,403 shutter activations.
Date of Birth: 1/20/2016.
Serial Number: 6096174.
Tonytee
My research suggests that the failure is a function of 'age', rather than of 'number of photos'
Neither nor!

It is more a question of (low) shutter activations and not using the Pentax often enough.

Several reasons for this:

1. The green solenoid has a stronger holding force
2. The green solenoid is made out of cheaper material (plastic and metal used for the horseshoe*)
3. This part which guides the movement of the horseshoe has more play
4. The horseshoe does magnetize (and de-magnetizing does NOT help)

The combination of those factors result in the horseshoe remaining stuck.

The filing method helps against the too strong magnet, but it does not help against the cheap materials and play.

One could compare this with bearings: A good bearing has lowest possible friction and lowest possible play.

This solenoid is a combination of all those factors. Through the filing method (or the soldering method) the horseshoe cannot be guided as well
anymore in the housing and tilts more towards the right side where the mechanism acts on. The horseshoe has MORE PLAY now! This tilt can finally result in the horseshoe being stuck again.

A little better solution would be the use of a weaker magnet, but this does not eliminate the other negative factors and it cannot solve those
*problems due to bad material:

- I have found corrosion on some horseshoes.
- I have found damage to the inner lining of the plastic of the body in which the horseshoe moves.

So DIY by using the white solenoid is the only option. Or finding somebody who repairs and guarantees that he uses the white solenoid!
02-03-2018, 04:50 AM   #83
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K-50 'White solenoid'

Can someone please explain to me what this "White-Solenoid" is?

02-04-2018, 12:29 AM   #84
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White Solenoid

QuoteOriginally posted by Rob-48 Quote
Can someone please explain to me what this "White-Solenoid" is?
Just read READ THIS THREAD and study very well the differences explained.

Do not fall for any CD-Rom Solenoid or similar but find the orig. white one made in Japan.
02-05-2018, 07:29 PM   #85
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QuoteOriginally posted by photogem Quote
Neither nor!

It is more a question of (low) shutter activations and not using the Pentax often enough.

Several reasons for this:

1. The green solenoid has a stronger holding force
2. The green solenoid is made out of cheaper material (plastic and metal used for the horseshoe*)
3. This part which guides the movement of the horseshoe has more play
4. The horseshoe does magnetize (and de-magnetizing does NOT help)

The combination of those factors result in the horseshoe remaining stuck.

The filing method helps against the too strong magnet, but it does not help against the cheap materials and play.

One could compare this with bearings: A good bearing has lowest possible friction and lowest possible play.

This solenoid is a combination of all those factors. Through the filing method (or the soldering method) the horseshoe cannot be guided as well
anymore in the housing and tilts more towards the right side where the mechanism acts on. The horseshoe has MORE PLAY now! This tilt can finally result in the horseshoe being stuck again.

A little better solution would be the use of a weaker magnet, but this does not eliminate the other negative factors and it cannot solve those
*problems due to bad material:

- I have found corrosion on some horseshoes.
- I have found damage to the inner lining of the plastic of the body in which the horseshoe moves.

So DIY by using the white solenoid is the only option. Or finding somebody who repairs and guarantees that he uses the white solenoid!
I've been trying to use mine once a week since sitting unused seems to be one of the things that leads to aperture failure.

Last edited by reh321; 02-05-2018 at 07:35 PM.
04-26-2018, 04:59 PM   #86
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This thread was sinking too far down in the list.
04-26-2018, 09:12 PM   #87
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QuoteOriginally posted by reh321 Quote
This thread was sinking too far down in the list.
This is nor a ship
04-27-2018, 05:50 AM   #88
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QuoteOriginally posted by photogem:
This is not a ship.
I guess you don't understand "Americanisms"

Last edited by reh321; 05-17-2018 at 12:43 PM.
05-17-2018, 12:43 PM   #89
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I believe the best way to test for this condition is to set the 'RAW/Fx' button to "stepdown" the aperture:
menu4 | Button Customization | RAW/FX ==> 'Optical Preview'


To test the mechanism, from the body set the aperture to some "intermediate" value, such as f/8, then press the 'RAW/Fx' button while looking through the viewfinder. The view through the viewfinder will dim, but not get totally dark, if the mechanism is working correctly.


My current theory is that failure to "exercise" the mechanism contributes to its failure, so I try to take at least one picture each week; if I don't come up with a reason to take a picture, I use the 'RAW/Fx' to exercise the mechanism.
05-18-2018, 10:17 AM   #90
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Don't know about specific cases, but in my case I used the mechanism all the time with manual lenses. It failed before 4500 shots, just outside of the 2 year warranty.

QuoteOriginally posted by reh321 Quote
I believe the best way to test for this condition is to set the 'RAW/Fx' button to "stepdown" the aperture:
menu4 | Button Customization | RAW/FX ==> 'Optical Preview'


To test the mechanism, from the body set the aperture to some "intermediate" value, such as f/8, then press the 'RAW/Fx' button while looking through the viewfinder. The view through the viewfinder will dim, but not get totally dark, if the mechanism is working correctly.


My current theory is that failure to "exercise" the mechanism contributes to its failure, so I try to take at least one picture each week; if I don't come up with a reason to take a picture, I use the 'RAW/Fx' to exercise the mechanism.
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