Sony TC-K511S 3 Head Dolby S/C/B Cassette Tape Deck, Serviced and Calibrated

This is my Sony TC-K511S cassette deck which I've owned since new. The top panel has a strange mottling effect, almost like rust, yet the top cover is made of aluminium, so cannot rust. There are a couple of small dings in the plastic along the top of the front panel, just above the Sony logo.

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