I Returned the K3

Started Mar 18, 2014 | Discussions thread
Russell Evans Forum Pro • Posts: 12,617
Re: I Returned the K3

Barry Pearson wrote:

But that still leaves the question: "why does the mirror flip?"

In a bit of silliness of thought, the Pentax engineers decided the best way to cool overheated electronics was to move volumes of air through the camera by flapping the mirror.

It seems that there isn't a mechanical link between the shutter and mirror since the shutter isn't affected by this issue, so there is some electronics controlling the mirror. Maybe it is in fact two circuits that control this, the first maybe being as simple as an open close gate at some point responsible only for sending the mirror up, with another circuit that monitors the state of the shutter to tell the mirror to drop when the shutter is closed. If the first circuit gets jammed, it sends the mirror up. The second circuit sees the shutter is closed, so sends it back down. The first circuit is still jammed, so down goes the mirror. this is repeated until the first circuit is able to correct its state or power is pulled.

I would assume this circuitry is always powered, maybe to allow for a faster boot of the camera, since turning off the camera doesn't stop the error condition. We know the SD card slot is always powered as inserting a card when the power is off does cause the write status light to come on, so it is possible there are other things in a low power state as well. This could be why pulling the battery is the only way to manually override what it happening.

I don't know and I'm just guessing, so this is worth exactly what you payed for it. I've never experienced the issue, so really I'm don't even have even that to judge by. Maybe you'll get a better answer from somebody that has?

Thank you

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