Air Conditioning - 3 lbs added and unit stopped cooling next day

Unit is split Rheem Classic X 2 ton unit with gas furnace about 14 years old. We have known for three years of a leak somewhere in unit. Had a problem last year with unit ceasing to blow air and making a low rumble/roar sound from attic condensor. Technician told us problem was a fan capacitor with intermitten problem. Changed out capacitor and unit operated fine rest of season. Now unit is acting up again. We are now researching the possibility of replacing the unit. Our question is this. Given the fan problem last year would it be advisable to replace the coil and exterior compressor unit? Of should we replace coil, compressor, air handler, and furnace pack? Furnace has never given any difficulties.

Your assistance is greatly appreciated. It's getting warm in the South and we have put this off long enough!

replacing a capacitor is a commen repair, no big deal. As far as the refrigerant leak was it repaired?
You say the system is acting up, whats it doing ?

Given the age, replacement is an option. With the new tax credits and more efficient equipment it may be a good investment for you.

Having a condensor unit up in an attic: Isn't that rather unusal? Isn't that a recipe for not perhaps getting the heat away from the coils? (some attics can get like 140 degrees up there.) Wouldn't you hear a compressor groan sound up there through the ceiling maybe? Anyone have comments on what he said? Any experience with seeing them there? Just curious. You'd think it be out in the yard or up on the roof. Maybe neither location is possible?

There isn't a cond unit in the attic, he just doesn't know the correct terminology

Need a little more information. What exactly is the problem now? Was it diagnosed by a technician?

If you just have a minor low cost problem, you don't need to replace equipment.