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08-31-2017, 11:20 AM   #1
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Green button fail, may be related to aperture control block failure

I need someone smarter than me to help answer this. I have had two acb failures to date, one in warranty on a k50 and another out of warranty on a k30 (my m42 camera now) so I am gun shy. I hadn't touched my k50 for awhile since acquiring a k5 iis. I started using it for convenience with a 24mm PK manual lens, but only shot wide open on AV. Today I tried using it in M mode with the green button and the camera did not respond. I choked and said this must be my 3rd time for an acb fail. And indeed, the FA-77mm went black too. So I switched to continuous shooting, 5 megapixel jpg and jpg only, cleared the card and shot a burst. The 77mm came back to life. But, the green button still failed to operate the PK lens. Just to be sure that it wasn't a lens issue, I put it on the k5 iis and the green button worked.

So my friends, is this a partially failed acb or something different? If it is still a partial acb failure who has had experience with a third party repair group who can fix this permanently for under $100.

If this is not a permanent fix, I might consider replacing this with an adaptist multimount and have a permanent Contax/Yashica K50 for $117. Any experience with that will also be appreciated

08-31-2017, 01:12 PM   #2
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Just to make sure, you do have green button metering enabled in the settings?
08-31-2017, 02:03 PM   #3
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Topsy I am certainly capable of making that mistake. However, my K50 seems to be set up exactly the way that my k5 iis is set up. Reading across the E-Line programming, page two line it goes - M TV AV TvShift. I hear the satisfying movement of the lens aperture in the k5 iis and nothing happens on the k5. Anybody need an m42 camera? Just glad the K5 iis keeps chunking along.
08-31-2017, 02:40 PM   #4
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Do you have Use Aperture Ring Enabled?

Do the lenses have conductive mounts? The green button may not stop down the lens in some cases on the K-50/30 when the lens mount is not conductive.

09-01-2017, 05:18 AM   #5
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QuoteOriginally posted by Not a Number Quote
Do you have Use Aperture Ring Enabled?

Do the lenses have conductive mounts? The green button may not stop down the lens in some cases on the K-50/30 when the lens mount is not conductive.
It looks conductive (bare metal) and stops down on the k5 iis. Aperture ring is enabled and in fact I've been shooting this AV wide open for over a week now.
09-01-2017, 07:38 AM   #6
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See this thread:
Dark exposure problems on K-30 or K-50? Read me first! - PentaxForums.com
09-01-2017, 09:31 AM   #7
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QuoteOriginally posted by Not a Number Quote
Not a Number - if I'm reading this thread correctly, it seems to indicate that if the acb is dead then green button metering with a K or M lens would also fail. This is what I originally thought until I resuscitated the acb by shooting a continuous burst. After that the green button still did not work with the e-dial set to M. The thread does not say, at least directly, that the green button fails when intermittent acb problems start to crop up (even though I now seem to be able to use DA and FA lenses on the k50). So I am left with that possibility of the green button failing because the acb fails once in awhile or I just have an unrelated green button failure in M mode.

So just to make sure that I'm not missing something I just now popped on a DA lens on the failing K50 and it happily produces images through a range of f stops. I checked my 24mm K type lens on the K5 iis and it still stops down. Both the K5 iis and the K50 have "Using Aperture Ring" set to 2. Both the K5 iis and the K50 have exactly the same set up for the E-dial M setting (= tvshift with the back dial controlling aperture and the front dial controlling shutter speed).

Am I misinterpreting what is in the thread you forwarded?
09-01-2017, 04:46 PM   #8
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Had a lengthy discussion with Ricoh support on this. Spoke to someone who has taken apart and fixed cameras so when I'm told no on has heard of this before, I can trust it. I also noticed that the optical preview (coded to my Raw/fx button) isn't working either. So it is either back to Precision or to a good third party or just no use M or K lenses as long as the acb stays unstuck. Thanks to all for any helpful suggestions.

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