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03-24-2021, 05:00 PM   #1
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K-S2 aperture block failure

Can aperture cleaning resolve this problem? I would like to use a local repair shop and they have suggested cleaning is a common fix, but solenoid parts replacement might be problematic.

03-24-2021, 06:11 PM   #2
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I would not expect a simple cleaning to resolve the normal aperture block failure. To gain access to the aperture assembly (even for cleaning) requires some disassembly of the camera, so it is likely just as easy to replace the solenoid at that point.
03-24-2021, 06:30 PM   #3
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I suggest reading the sticky posts on the aperture problem. See the index for this forum:

Pentax K-S1 & K-S2 - PentaxForums.com
03-24-2021, 06:47 PM - 2 Likes   #4
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My K-30 just started producing dark images.
I decided not to fix it ( at least for a while ) , instead dedicate it to use it with manual K ,M Kmount & M42 lenses.

03-24-2021, 08:03 PM - 1 Like   #5
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QuoteOriginally posted by ydenk Quote
Can aperture cleaning resolve this problem? I would like to use a local repair shop and they have suggested cleaning is a common fix, but solenoid parts replacement might be problematic.
That would only make sense if the problem only happened with one lens.
03-25-2021, 09:06 AM - 1 Like   #6
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Aperture solenoid replacement is not difficult at all if you know how to use a point soldering device (never use something like a propane based device...)

I have opened both a K-S1 and a K-S2 and the K-S2 is quite a bit simpler to open up. The linked K-S1/K-S2 forum has all the instructions, with pictures, to get your solenoid replaced. Just make sure to get a white Matsushita solenoid, not a green replacement solenoid. And it has to be from an old Pentax camera, or made specifically for Pentax. They sell some on Ebay that are a totally wrong voltage, and could damage your camera permanently.

When disassembling, be gentle when taking the top and the front of the camera off. There are some connectors that look fragile, and could end up getting ripped out easily. If you don't feel confident in doing the work, then it's probably best not to. I'd advise you to either use the camera as a manual-aperture only camera, or sell it to someone who wants to fix it (or use it for manual lenses). Then I would buy a camera that would not have that problem - depending on your budget, your options vary. For a lower budget I'd look into a K-5II or K-5IIs (around 300 dollars), if you have more to invest there's the K-3/K-3II and the KP, all excellent options and will never have aperture block failure.
03-25-2021, 04:28 PM   #7
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QuoteOriginally posted by ydenk Quote
Can aperture cleaning resolve this problem? I would like to use a local repair shop and they have suggested cleaning is a common fix, but solenoid parts replacement might be problematic.
For sure don't use that local repair shop if they said this.
Then they talk nonsense³:

- ABF (Aperture-block-failure) happens because the solenoid is stuck.
- One does not replace parts of the solenoid but the whole solenoid:
Why you shouldn't file/sand the plunger of the green Chinasolenoid but replace it - PentaxForums.com

- Suggesting to clean the aperture itself indicates that they think it is a lens/diaphragm problem, i.e. sticky aperture/blades
This does never lead to ABF but only to problems with this particular lens, other lenses work alright

The only real solution is exchanging the solenoid for a true DSLR solenoid made in Japan:
A LITTLE BIT OF HISTORY: Development of the solenoid in Pentax cameras - PentaxForums.com

03-26-2021, 07:49 AM - 1 Like   #8
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Thank you all - I have several old manual aperture lens and will go the route
03-29-2021, 04:28 AM   #9
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Too bad, kind of a castrated K-S2.
The K-S2 is worth it for sure to be repaired.
07-19-2021, 10:33 AM   #10
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goodluck!
07-19-2021, 01:41 PM - 1 Like   #11
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QuoteOriginally posted by loji Quote
goodluck!
Meaning what?

Last edited by photogem; 04-04-2022 at 02:25 AM.
08-28-2021, 12:55 PM   #12
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QuoteOriginally posted by ydenk Quote
Can aperture cleaning resolve this problem? I would like to use a local repair shop and they have suggested cleaning is a common fix, but solenoid parts replacement might be problematic.
You can always shoot PLM lenses or vintage lenses manually.....all is not lost.

---------- Post added 08-28-21 at 12:56 ----------

QuoteOriginally posted by photogem Quote
A "nonsense posting" just to get your 6 postings for the "Giveaway"?
Is that all *you* have to give?
ROFLOL.....

---------- Post added 08-28-21 at 12:57 ----------

QuoteOriginally posted by ydenk Quote
Thank you all - I have several old manual aperture lens and will go the route
The latest PLM lenses work just fine also.
08-28-2021, 08:23 PM   #13
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QuoteOriginally posted by Ronald Oakes Quote
You can always shoot PLM lenses or vintage lenses manually.....all is not lost.

---------- Post added 08-28-21 at 12:56 ----------


ROFLOL.....

---------- Post added 08-28-21 at 12:57 ----------


The latest PLM lenses work just fine also.
The bigger issue is Kaf4. Electronic aperture control is insurmountable on bodies that don’t support it - unless wide open is all you need.
08-29-2021, 02:30 PM   #14
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QuoteOriginally posted by UncleVanya Quote
The bigger issue is Kaf4. Electronic aperture control is insurmountable on bodies that don’t support it - unless wide open is all you need.
Right...and the K-S2 does !
08-29-2021, 10:52 PM   #15
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QuoteOriginally posted by Ronald Oakes Quote
Right...and the K-S2 does !
Except the K500 every Pentax having the China Solenoid for aperture-control do have that possibility.
K30 with *our* firmware-update which now became the "golden standard" for every official repair shop!
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