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Anders Skjeggestad
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, November 02, 2005 - 06:51 am: | 
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The camera in question (Pentax ME, not Super) works perfectly without battery and on mechanical speed, but when battery is inserted it jams when set on auto. The mirror goes up, the first curtain goes down, but the second does not and stops the cycle. To unjam it I have to either move the mode dial to X or pull down on the aperture lever to the left in the mirror box. The light meter seems to show correct exposure, but stays lighted until I unjam the camera.
Any suggestions are highly appreciated. |
Paolo Amedeo
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, November 02, 2005 - 09:42 am: |
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Hi Anders,
A couple of questions: What do you mean with "mechanical time": only the flash synchro time or, using it with battery, any exposure time in manual mode?
If I recall correctly, in this camera the release button trigger the mirror. Once the mirror is completely lifted, it triggers the shutter: as it releases the first curtain, it sends a signal to the circuit to "time" the exposure (i.e. to decide when the solenoid should release the second curtain). If the contacts of the switch are dirty, the circuit won't ever sense that the first curtain has started. Moving the selector to "X", in this camera, I think that it simply cut out of the circuit the solenoid, letting the second curtain go as soon as the first curtain has ended it's travel...
Such switch is made of two small copper blades that, when the shutter is cocked, don't touch each-other. I however don't remember if, in this camera are located at the bottom or more inside, together with the curtain assembly...
I'll look if I do have one around and I will check for you.
If, instead, the problem is only on the "auto" setting, then, I would give a trial cleaning up all the contacts of the ISO dial and aperture simulator, however with very little hope that it would correct the problem...
Paolo |
Anders Skjeggestad
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, November 02, 2005 - 12:16 pm: |
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Hello Paolo,
Thank you for your quick and informative response.
To be specific, only the flash synchro speed works. The electronically controlled speeds do not. Unlike the ME Super there is no electronically controlled manual mode on the ME, only aperture priority, so it sounds that your theory about the switch might be correct.
If you could find out where the switch is located I would be very grateful.
Regards, Anders |
Paolo Amedeo
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, November 02, 2005 - 11:29 pm: |
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Hi Anders,
unfortunately I have bad news: the switch I was talking about is not readily accessible at the bottom of the camera. It could be (most likely) together with the shutter group or it could be accessible from the top, under the mode/speed selector knob...
Therefore, in order to access it, it would be necessary to take apart the whole camera...
I would therefore suggest that, before doing that, you would listen some other opinion: the cause of the problem could be a bad component (most likely a bad capacitor) on the circuit... There should be way to test this hypothesis (and, possibly, to replace the bad element without having to disassemble the whole camera...
Unfortunately, I don't have too much experience with the electronics...
Paolo |
Anders Skjeggestad
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, November 03, 2005 - 12:35 am: |
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Hello Paolo,
Thanks for checking. I will try to take the top of (I have done this before) to see if there are any dirty contacts under the mode dial. If this does not work I will have to try to find someone who can help me further.
Thank you for your help.
Anders |
Don
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, November 03, 2005 - 06:39 am: |
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ME has 2 mech. speeds, the flash sync (125) & B. If both of these work, then it sounds like a circuit problem either the asa/comp dial or the dia. resistor. I have some service notes for this model that I could scan & send if needed.
Don |
Anders Skjeggestad
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, November 04, 2005 - 07:16 am: |
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Hello Don,
Both the flash sync and the B setting works. It is only with batteries it is behaving weird. After trying it some more yesterday I found that sometimes the shutter releases on electronic speeds, but it is very erratic. Most of the time it jams. The leds now show overexposure a fraction of a second and then drop to underexposure and flickers there when pressing the shutter release halfway.
I would appreciate the service notes if it is not too much trouble.
Anders |
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