Odd behaviour from Super A - aperture doesn't stop down

Jonathan Mac · 07-23-2014, 06:57 AM

I have a Super A I've yet to run a roll of film through. I have dry-fired it quite a few times and have found that sometimes it starts firing the shutter but without stopping down the aperture to what is set on the lens. I am using M lenses.

If I take the lens off I see that the stop-down lever in the mount barely moves when it does this. I think it also flashes P125 in the small screen on top, but as I need to be behind to see the screen but in front to see the aperture, it's hard to be 100% certain if it always does this.

Has anyone seen this behaviour? Could it be due to low batteries or is there something more serious happening?

Many thanks

Mactaus · 07-28-2014, 07:12 AM

Hi I have only ever had aperture problems whith one lens on my Super A and that happens on my K100d super as well however you may find something in the manual Link Here as there is a list of errors around page 30ish

Jonathan Mac · 07-28-2014, 11:17 PM

Thanks for the link -I've had a look but no help. I think it's a battery problem but it has new LR44s (second set) and behaves the same. LR44s seem to be only available with alkaline chemistry these days so there's nothing else I can try. I have read that devices originally designed for batteries with other chemistries can have problems due to differences in voltage etc.

I've had another play and sometimes it just goes into 'P' mode and the aperture doesn't stop down, though that shouldn't be possible with a lens without an 'A' setting.

johnha · 07-29-2014, 02:18 PM

Hi Jonathan,

I found some SR44s from a seller on ebay when trying to get a KX working, although I don't think it will help much. I presume you've tried cleaning the contacts on the lens mount.

Does the DoF lever stop the aperture down (it will always stop an A lens in 'A' to minimum aperture)? Maybe cautious cycling of the DoF lever might help (or might not)!

I think the stop-down lever on the 'A' series cameras moved proportionately to the aperture the camera wanted to use - which might explain only slight movement?

John.

Jonathan Mac · 07-30-2014, 12:02 AM

Hi John, I've tried cleaning the contacts, though not with alcohol yet. I saw some 1.4v zinc-air batteries of the same size yesterday and was wondering if they might provide a more consistent voltage? Not sure how long they'd last though.

There's no physical problem with the lever - it moves smoothly. It's just that the camera sometimes thinks it's in P mode.

stevebrot · 07-30-2014, 07:59 AM

Originally posted by Jonathan Mac

LR44s seem to be only available with alkaline chemistry these days so there's nothing else I can try.

Your camera was designed to use SR44 silver cells. Those have a long life and a more consistent performance than the alkaline LR44. Both types have the same voltage (1.5v) when fresh, but the LR44 voltage drops significantly as the battery is depleted. Here in the U.S., both types are readily available with the silver cells being more common.

As for the aperture lever...It should move full range when no lens is mounted and the mode is on "B".

In regards to "P" mode...that should only happen if the "A" contact pin (the one that is recessed with a black insulating ring) on the body is engaged by the lens. Cleaning should not make any difference in your case. The same would be true for voltage.

I suspect that your camera has an internal fault.

Steve

Jonathan Mac · 10-13-2014, 10:11 PM

I took this camera out on an organised photo-walk at the weekend, having run 25 shots through it after changing the alkaline batteries for better silver-oxide ones, and it let me down again. I had thought that the better batteries had fixed the problem but no.

Does anyone know if it's possible to permanently disable the "P" option by severing a connection to one of the mount contacts?

**pentaxus** · 10-13-2014, 10:55 PM

As stevebrot correctly mentioned, the issue with this camera has nothing to do with the "P" mode. The aperture control mechanism is not working. Even in manual mode, this same mechanism moves the aperture lever on the lens. Sadly the part is no longer available. Maybe a technician could take the camera apart and try lubricating the mechanism but they might not be excited to do a lot of work for something might not produce results.

titrisol · 10-15-2014, 08:05 AM

That is not a battery problem, does it work OK with other lenses?
When you press the depth of field preview lever, does it change the aperture?

Using P mode on the M lenses is not the best idea, even though it should work as A mode
I gave mine away, so I can not test anymore.

manntax · 10-15-2014, 08:15 AM

I just took mine out and checked with M lenses - works perfectly and stops down as expected. Also correctly adjusts the speed in P mode with M lens.

Not a Number · 10-16-2014, 11:22 AM

I seem to recall a post where someone had problems with the aperture lever on the body sticking or not moving completely. He said Eric Henderson told him to try putting a drop of lighter fluid on the lever and if this freed up the problem to then put a drop of oil on it. He didn't say what oil to use though.

It goes without saying you want to take care and not flood the camera with these fluids.

titrisol · 10-16-2014, 01:29 PM

A drop of lighter fluid wont hurt anything....
Since Jonathan is in Spain, lighter fluid is "Nafta para encendedores"
and probabably a drop of sewing machine oil would do it

Jonathan Mac · 10-16-2014, 01:34 PM

It can't be a physical problem with the lever as the camera thinks it's in P mode, which is not possible except with A lenses. I'm using it with M lenses.

I think I'll open it up and have a tinker, as it's already severely unreliable I've not got much to lose.

asad ali · 10-21-2014, 03:29 AM

I have a Super A I've yet to run a roll of film through. I have dry-fired it quite a few times and have found that sometimes it starts firing the shutter but without stopping down the aperture to what is set on the lens.

_____
shafiq

Jonathan Mac · 10-21-2014, 01:45 PM

Originally posted by asad ali

I have a Super A I've yet to run a roll of film through. I have dry-fired it quite a few times and have found that sometimes it starts firing the shutter but without stopping down the aperture to what is set on the lens.

_____
shafiq

Does the screen show it in "P" mode even using a lens not in the "A" position?

07-23-2014, 06:57 AM	#1
Jonathan Mac Pentaxian Join Date: Apr 2009 Location: Madrid, Spain Posts: 10,911	Odd behaviour from Super A - aperture doesn't stop down I have a Super A I've yet to run a roll of film through. I have dry-fired it quite a few times and have found that sometimes it starts firing the shutter but without stopping down the aperture to what is set on the lens. I am using M lenses. If I take the lens off I see that the stop-down lever in the mount barely moves when it does this. I think it also flashes P125 in the small screen on top, but as I need to be behind to see the screen but in front to see the aperture, it's hard to be 100% certain if it always does this. Has anyone seen this behaviour? Could it be due to low batteries or is there something more serious happening? Many thanks

10-21-2014, 03:29 AM	#14
asad ali New Member Join Date: Oct 2014 Posts: 2	zcv I have a Super A I've yet to run a roll of film through. I have dry-fired it quite a few times and have found that sometimes it starts firing the shutter but without stopping down the aperture to what is set on the lens. _____ shafiq

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07-28-2014, 07:12 AM	#2
Mactaus New Member Join Date: Dec 2013 Posts: 11	Hi I have only ever had aperture problems whith one lens on my Super A and that happens on my K100d super as well however you may find something in the manual Link Here as there is a list of errors around page 30ish

07-28-2014, 11:17 PM	#3
Jonathan Mac Pentaxian Join Date: Apr 2009 Location: Madrid, Spain Posts: 10,911 Original Poster	Thanks for the link -I've had a look but no help. I think it's a battery problem but it has new LR44s (second set) and behaves the same. LR44s seem to be only available with alkaline chemistry these days so there's nothing else I can try. I have read that devices originally designed for batteries with other chemistries can have problems due to differences in voltage etc. I've had another play and sometimes it just goes into 'P' mode and the aperture doesn't stop down, though that shouldn't be possible with a lens without an 'A' setting.

07-29-2014, 02:18 PM	#4
johnha Veteran Member Join Date: Apr 2012 Location: Lancashire, UK Photos: Albums Posts: 1,155	Hi Jonathan, I found some SR44s from a seller on ebay when trying to get a KX working, although I don't think it will help much. I presume you've tried cleaning the contacts on the lens mount. Does the DoF lever stop the aperture down (it will always stop an A lens in 'A' to minimum aperture)? Maybe cautious cycling of the DoF lever might help (or might not)! I think the stop-down lever on the 'A' series cameras moved proportionately to the aperture the camera wanted to use - which might explain only slight movement? John.

07-30-2014, 12:02 AM	#5
Jonathan Mac Pentaxian Join Date: Apr 2009 Location: Madrid, Spain Posts: 10,911 Original Poster	Hi John, I've tried cleaning the contacts, though not with alcohol yet. I saw some 1.4v zinc-air batteries of the same size yesterday and was wondering if they might provide a more consistent voltage? Not sure how long they'd last though. There's no physical problem with the lever - it moves smoothly. It's just that the camera sometimes thinks it's in P mode.

07-30-2014, 07:59 AM	#6
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by Jonathan Mac LR44s seem to be only available with alkaline chemistry these days so there's nothing else I can try. Your camera was designed to use SR44 silver cells. Those have a long life and a more consistent performance than the alkaline LR44. Both types have the same voltage (1.5v) when fresh, but the LR44 voltage drops significantly as the battery is depleted. Here in the U.S., both types are readily available with the silver cells being more common. As for the aperture lever...It should move full range when no lens is mounted and the mode is on "B". In regards to "P" mode...that should only happen if the "A" contact pin (the one that is recessed with a black insulating ring) on the body is engaged by the lens. Cleaning should not make any difference in your case. The same would be true for voltage. I suspect that your camera has an internal fault. Steve

10-13-2014, 10:11 PM	#7
Jonathan Mac Pentaxian Join Date: Apr 2009 Location: Madrid, Spain Posts: 10,911 Original Poster	I took this camera out on an organised photo-walk at the weekend, having run 25 shots through it after changing the alkaline batteries for better silver-oxide ones, and it let me down again. I had thought that the better batteries had fixed the problem but no. Does anyone know if it's possible to permanently disable the "P" option by severing a connection to one of the mount contacts?

10-13-2014, 10:55 PM	#8
pentaxus Site Supporter Join Date: Jun 2010 Location: Central Coast, CA Posts: 1,320	As stevebrot correctly mentioned, the issue with this camera has nothing to do with the "P" mode. The aperture control mechanism is not working. Even in manual mode, this same mechanism moves the aperture lever on the lens. Sadly the part is no longer available. Maybe a technician could take the camera apart and try lubricating the mechanism but they might not be excited to do a lot of work for something might not produce results.

10-15-2014, 08:05 AM	#9
titrisol Pentaxian Join Date: Dec 2007 Location: In the most populated state... state of denial Photos: Gallery \| Albums Posts: 1,854	That is not a battery problem, does it work OK with other lenses? When you press the depth of field preview lever, does it change the aperture? Using P mode on the M lenses is not the best idea, even though it should work as A mode I gave mine away, so I can not test anymore.

10-15-2014, 08:15 AM	#10
manntax Veteran Member Join Date: Jan 2012 Photos: Albums Posts: 1,972	I just took mine out and checked with M lenses - works perfectly and stops down as expected. Also correctly adjusts the speed in P mode with M lens.

10-16-2014, 11:22 AM	#11
Not a Number Moderator Join Date: Mar 2012 Location: Venice, CA Posts: 10,526	I seem to recall a post where someone had problems with the aperture lever on the body sticking or not moving completely. He said Eric Henderson told him to try putting a drop of lighter fluid on the lever and if this freed up the problem to then put a drop of oil on it. He didn't say what oil to use though. It goes without saying you want to take care and not flood the camera with these fluids.

10-16-2014, 01:29 PM	#12
titrisol Pentaxian Join Date: Dec 2007 Location: In the most populated state... state of denial Photos: Gallery \| Albums Posts: 1,854	A drop of lighter fluid wont hurt anything.... Since Jonathan is in Spain, lighter fluid is "Nafta para encendedores" and probabably a drop of sewing machine oil would do it

10-16-2014, 01:34 PM	#13
Jonathan Mac Pentaxian Join Date: Apr 2009 Location: Madrid, Spain Posts: 10,911 Original Poster	It can't be a physical problem with the lever as the camera thinks it's in P mode, which is not possible except with A lenses. I'm using it with M lenses. I think I'll open it up and have a tinker, as it's already severely unreliable I've not got much to lose.

10-21-2014, 01:45 PM	#15
Jonathan Mac Pentaxian Join Date: Apr 2009 Location: Madrid, Spain Posts: 10,911 Original Poster	Originally posted by asad ali I have a Super A I've yet to run a roll of film through. I have dry-fired it quite a few times and have found that sometimes it starts firing the shutter but without stopping down the aperture to what is set on the lens. _____ shafiq Does the screen show it in "P" mode even using a lens not in the "A" position?