DC blocker in portland weather FB loop causes -nan

[glocke01]

I was just randomizing and getting weird behavior, I thought adding a DC blocker might prevent blowups, but, as you see, that did not solve the problem. :)

[glocke01]

Connecting the loop sends the outputs of 4DCB and PW to -nan. Remove both connections between PW and 4DCB, now the output of 4DCB is 0 and PW is still at -nan, and nothing I can do fixes it (clear buffer button, initialize do nothing).

[almostEric]

any chance I can get this patch? I tried inserting the 4dcb and doing a lot of randomizing and could not reproduce. :/