Search for the PSB part number - it's the one upside down in your second picture with I think 2700648 RevB, or any similar ones listed there. It is how I have found many obscure PSB's before.
Also, get a toothbrush with some metho, and scrub the corrosion off (gently). Then respray it with clear acrylic varnish (automotive) or at least hairspray (many coats). Might just work for you again for a while
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