>>3469433The Pentax ME and it's relatives have an issue with disintegrating bushings that results in shutter winding problems, sluggish mirror or delay in shutter or mirror release. A complete CLA (clean, lube, adjust) sorts it out.
are you testing it in manual mode, as in actually selecting the shutter speed, or auto? the ME in auto can go into some really long exposures under some low light/ASA settings conditions. if the shutter hangs open, just let it sit for a while until it shuts back on its own, don't poke it.
also, do you get the same problems on the mechanical 125x setting?
another possibility is that your batteries are dying. bad batteries cause weird shutter behavior in manual and auto modes, like shutter releasing but speeds being way off.
if it's worth it to get it CLA'd depends on how much the tech charges. local tech here does it for $20 to $25 so to get a $18 Pentax ME F back into working condition then yes, it's worth it. but if they charge like $50 then hell no. rather look for another working camera.