Pentax 67, shutter sticks open in portrait orientation

riffraffselbow · 06-14-2020, 05:42 PM

Hey; this is a weird one! I got a great deal on an ebay-special Pentax 67; 3rd gen (aka "67"), reasonably clean, shutter is reasonably accurate (we'll get to the problem later) at all speeds, etc, etc. There was a shutter curtain repair (due to a jam tearing two holes in it) but it seems like it was done fairly well and so far I've had no issue with the shutter outright jamming or the curtain getting bunched up or hung up anywhere, at least as far as I can tell. Both curtains return to where they should be, without kinks or creases or anything like that. In short, a beater, but functional? However, there is one issue: the shutter does not consistently close when the camera is oriented on its side, angled downward, or on its back. I assume this is because some spring is not strong enough after 30 years of heavy use to close the shutter working against the force of gravity, but I'm not sure.

I guess my question is: has anyone else had this problem (shutter sticking open with the mirror up, exacerbated by "weird" angles of the camera), and was it due to a dirty/dry shutter mechanism or alternatively was it a sign that the camera was just on its last legs and not economically repairable or whatever? specifically, the shutter opens cleanly, with or without MLU, but then the shutter just doesn't close and the mirror doesn't cycle, until the camera is brought back into "landscape" orientation and, in some cases, gently tapped to convince the mechanism to unstick.

I imagine this may be the remnants of the shutter issues that caused it to jam bad enough to tear the shutter curtain in the first place; it certainly wouldn't surprise me. To be honest, for what I paid, given I'm an amateur, I'm okay with this problem eating a shot or two a roll, but if anyone has any user-service suggestions I'm game to try gently poking at something or whatever. I will also note that I haven't put real film through the camera yet, this has all been "dry-fire" testing.

johnha · 06-15-2020, 02:34 AM

I have had a similar impression with my 6x7 Mlu when held in portrait (shutter release at top) orientation, when shooting film. I haven't dry fired it (I don't want to risk wrecking anything) and haven't had a chance to get film developed (due to lockdown) to check. In my case, I perceive a delay with the finder blackout clearing, I had thought it might be the mirror failing to drop quickly enough rather than the shutter sticking open. With the lockdown easing I hope to get the film developed soon...

tuco · 06-15-2020, 12:51 PM

Portrait orientation can put the camera in two different orientations relative to which way the shutter curtain is opening (up or down). Does it stick both ways?

riffraffselbow · 06-16-2020, 10:33 PM

Originally posted by tuco

Portrait orientation can put the camera in two different orientations relative to which way the shutter curtain is opening (up or down). Does it stick both ways?

Yep, both directions, and near 100% of the time when upside down; it seems to be getting better with some shutter actuations, though, it's now mostly not freezing up (except upside down but that seems like a pretty reasonable limitation given the size of the mirror etc). One other issue that I may have been confusing with this at least some of the time was that my shutter speed knob doesn't have the clicky detents and instead spins 'freely" and it seems the shutter will open but not close if the speed selector is 'between' speeds (i.e. not making contact with a contact pad)

Silent Street · 06-17-2020, 09:54 PM

Originally posted by riffraffselbow

One other issue that I may have been confusing with this at least some of the time was that my shutter speed knob doesn't have the clicky detents and instead spins 'freely" and it seems the shutter will open but not close if the speed selector is 'between' speeds (i.e. not making contact w

This means the shutter speed dial indents have been stripped, so a full repair of both the dial and the indent pawl and probably the circuit if it has been abraded, would be required. There is one condition that is normal with the setting of the shutter speed, when it is placed in the black space after 1000 and X or B. The shutter can be opened but will not close until the dial has been set to one of the marked speeds., and this is intentional.

I suspect your camera requires a whole replacement shutter assembly and counterweight. There are no new assemblies available; parts are scavenged from like-cameras, which introduces reliability and redundancy problems, so all up, you may be better off buying a replacement 67 camera with no faults.

riffraffselbow · 06-17-2020, 11:13 PM

Originally posted by Silent Street

This means the shutter speed dial indents have been stripped, so a full repair of both the dial and the indent pawl and probably the circuit if it has been abraded, would be required. There is one condition that is normal with the setting of the shutter speed, when it is placed in the black space after 1000 and X or B. The shutter can be opened but will not close until the dial has been set to one of the marked speeds., and this is intentional.

I suspect your camera requires a whole replacement shutter assembly and counterweight. There are no new assemblies available; parts are scavenged from like-cameras, which introduces reliability and redundancy problems, so all up, you may be better off buying a replacement 67 camera with no faults.

It works perfectly fine ~80% of the time or better, it just fails occasionally. When the problem is the dial being "between" settings, jogging it a bit (e.g. between 125 and 60) will close it, so presumably it's not that far advanced. I'm sure it'll get worse over time, but I paid ~$100 shipped so I'm totally happy to deal with some faults and wasted shots.

riffraffselbow · 06-21-2020, 08:56 PM

lens arrived in the mail today; suffice it to say there's nothing wrong with this cheapie! a full frame and 100%@6400dpi crop (from different image) attached. ended up shooting this test roll mostly at 1/60th but I don't suspect I'll have shutter issues with other speeds, either.

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06-14-2020, 05:42 PM	#1
riffraffselbow Junior Member Join Date: Dec 2019 Photos: Gallery Posts: 41	Pentax 67, shutter sticks open in portrait orientation Hey; this is a weird one! I got a great deal on an ebay-special Pentax 67; 3rd gen (aka "67"), reasonably clean, shutter is reasonably accurate (we'll get to the problem later) at all speeds, etc, etc. There was a shutter curtain repair (due to a jam tearing two holes in it) but it seems like it was done fairly well and so far I've had no issue with the shutter outright jamming or the curtain getting bunched up or hung up anywhere, at least as far as I can tell. Both curtains return to where they should be, without kinks or creases or anything like that. In short, a beater, but functional? However, there is one issue: the shutter does not consistently close when the camera is oriented on its side, angled downward, or on its back. I assume this is because some spring is not strong enough after 30 years of heavy use to close the shutter working against the force of gravity, but I'm not sure. I guess my question is: has anyone else had this problem (shutter sticking open with the mirror up, exacerbated by "weird" angles of the camera), and was it due to a dirty/dry shutter mechanism or alternatively was it a sign that the camera was just on its last legs and not economically repairable or whatever? specifically, the shutter opens cleanly, with or without MLU, but then the shutter just doesn't close and the mirror doesn't cycle, until the camera is brought back into "landscape" orientation and, in some cases, gently tapped to convince the mechanism to unstick. I imagine this may be the remnants of the shutter issues that caused it to jam bad enough to tear the shutter curtain in the first place; it certainly wouldn't surprise me. To be honest, for what I paid, given I'm an amateur, I'm okay with this problem eating a shot or two a roll, but if anyone has any user-service suggestions I'm game to try gently poking at something or whatever. I will also note that I haven't put real film through the camera yet, this has all been "dry-fire" testing.

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06-15-2020, 02:34 AM	#2
johnha Veteran Member Join Date: Apr 2012 Location: Lancashire, UK Photos: Albums Posts: 1,155	I have had a similar impression with my 6x7 Mlu when held in portrait (shutter release at top) orientation, when shooting film. I haven't dry fired it (I don't want to risk wrecking anything) and haven't had a chance to get film developed (due to lockdown) to check. In my case, I perceive a delay with the finder blackout clearing, I had thought it might be the mirror failing to drop quickly enough rather than the shutter sticking open. With the lockdown easing I hope to get the film developed soon...

06-15-2020, 12:51 PM	#3
tuco Pentaxian Join Date: Jul 2009 Location: Pugetopolis Posts: 11,027	Portrait orientation can put the camera in two different orientations relative to which way the shutter curtain is opening (up or down). Does it stick both ways?

06-16-2020, 10:33 PM	#4
riffraffselbow Junior Member Join Date: Dec 2019 Photos: Gallery Posts: 41 Original Poster	Originally posted by tuco Portrait orientation can put the camera in two different orientations relative to which way the shutter curtain is opening (up or down). Does it stick both ways? Yep, both directions, and near 100% of the time when upside down; it seems to be getting better with some shutter actuations, though, it's now mostly not freezing up (except upside down but that seems like a pretty reasonable limitation given the size of the mirror etc). One other issue that I may have been confusing with this at least some of the time was that my shutter speed knob doesn't have the clicky detents and instead spins 'freely" and it seems the shutter will open but not close if the speed selector is 'between' speeds (i.e. not making contact with a contact pad)

06-17-2020, 09:54 PM	#5
Silent Street Veteran Member Join Date: Nov 2011 Location: Castlemaine, Victoria, AUS Photos: Albums Posts: 1,151	Originally posted by riffraffselbow One other issue that I may have been confusing with this at least some of the time was that my shutter speed knob doesn't have the clicky detents and instead spins 'freely" and it seems the shutter will open but not close if the speed selector is 'between' speeds (i.e. not making contact w This means the shutter speed dial indents have been stripped, so a full repair of both the dial and the indent pawl and probably the circuit if it has been abraded, would be required. There is one condition that is normal with the setting of the shutter speed, when it is placed in the black space after 1000 and X or B. The shutter can be opened but will not close until the dial has been set to one of the marked speeds., and this is intentional. I suspect your camera requires a whole replacement shutter assembly and counterweight. There are no new assemblies available; parts are scavenged from like-cameras, which introduces reliability and redundancy problems, so all up, you may be better off buying a replacement 67 camera with no faults.

06-17-2020, 11:13 PM	#6
riffraffselbow Junior Member Join Date: Dec 2019 Photos: Gallery Posts: 41 Original Poster	Originally posted by Silent Street This means the shutter speed dial indents have been stripped, so a full repair of both the dial and the indent pawl and probably the circuit if it has been abraded, would be required. There is one condition that is normal with the setting of the shutter speed, when it is placed in the black space after 1000 and X or B. The shutter can be opened but will not close until the dial has been set to one of the marked speeds., and this is intentional. I suspect your camera requires a whole replacement shutter assembly and counterweight. There are no new assemblies available; parts are scavenged from like-cameras, which introduces reliability and redundancy problems, so all up, you may be better off buying a replacement 67 camera with no faults. It works perfectly fine ~80% of the time or better, it just fails occasionally. When the problem is the dial being "between" settings, jogging it a bit (e.g. between 125 and 60) will close it, so presumably it's not that far advanced. I'm sure it'll get worse over time, but I paid ~$100 shipped so I'm totally happy to deal with some faults and wasted shots.