I agree with Mr. P. Contact the needle Doctor. As far as the hum is concerned, do you have the ground from the TT connected? Also, some Grado's are prone to a hum from what I have read.

A nice cartridge is the Nagaoka MP-110. It is forgiving of record noise like hiss and pops. It leans on the slightly warmer side of neutral which is a good thing with inexpensive TT's and cartridges. Otherwise consider an Ortofon 2M Red cartridge.

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