LM63: solution select

Hello Denny,

It is not a drop in replacement, but has similar functionality.  The LM63 only has TACH input for and 1 remote and local sensor. 

The LM87 offers 2 remote and 1 local sensor similar to the SCT221, but 2 TACH inputs.  This may still work if they are monitoring 2 fans only.

https://www.ti.com/product/LM87