Sony DSC-F707 will not turn on or off using power switch.

My DSC-F707 will not turn ON or OFF using the power switch. I have a fully charged battery. After "resetting" the camera, it will boot up and continue to take pictures and function normally as long as I don't let the timer get to the automatic power-off limit. Once it powers itself down, I have to "reset" it again to get it to function. Is this an expensive, and therefore worthless (given the age of the camera) electro-mechanical repair, or, is there another fix? I have tried the only fix in the operator's manual which is to set the camera to the "review" function and operate the switch at that position.

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