What Mr. Simpson said, but I would like to add one more thing.? I want to elaborate on sealing.? The aluminum is anodized making an porous oxide.? Then is it dyed.? Then SEALED in a follow up process.? Often the dye will fail from UV, or the more likely, the sealing might be failing.? I say sealing, because I have many power supplies with purple heatsinks that never saw the light of day.? So just plain dye degradation or sealing failure is my guess (not ruling our UV in your case).? Both could be the result of sub-standard chemicals or improper process (length, temperature).
Bob
