jhmos, I believe there's a relatively simple explanation for the manufacturing defect which has troubled me as well. If I'm correct, then so are they: There's no real 'fix' for the problem because it is a design flaw deep within the circuitry of the camera.
Pentax/Ricoh modified this camera (K3) extensively during the design phase, adding many new wonderful features. What they did NOT do was adequately compensate for the additional current draw and resulting voltage drop to the circuit board. There is a window or voltage range in which the electronic components will behave normally. Outside that range, results will be unpredictable/frustrating. Well designed electronic devices have a voltage regulator that more or less guarantees the supplied voltage remains within the desired window/range. In this instance, that window was either too narrow or improperly set to allow for variables such as disparate batteries (rechargeable vs. zinc battery voltages, temperature, etc.). The runaway mirror problem damages the camera by tearing up the baffle while rapidly flopping. Crumbs from the damage will land on the K3 sensor, further degrading its performance. This is a deep seated manufacturing flaw for which the company has never fully accepted/acknowledged responsibility. It's erratic because the conditions leading to it are variable. The camera also (for the same reason and as erratically) sometimes misses a shot or does not record video/pics to one of the two memory cards. The camera is, therefore, unreliable. Ricoh should remedy this for ALL purchasers of the K3 regardless of their reticence to send off their gear/camera to some distant repair shop only to receive a SOP, excuses, or mollification. Ricoh sold EVERYONE who purchased a K3 a lemon, regardless of whether they actually ran into one of the set of conditions which cause the camera to fail or not. Not everyone who purchased a Corvair died. That doesn't mean the car was safe. Ricoh sold a lawn mower that cuts grass MOST of the time.
Purchasers might notice battery life on the K3 is considerably shorter than the K5. The reason (and consistent with the above reasoning) is simple enough: Its circuitry draws/requires MORE power!
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