Summary
Following ID 1649 & 1663 electronics for the FSS of the North path has been hooked up.
The North cavity was ready for locking today.

Conclusion
The error-signal of the North PDH does not look right. The cavity can be locked but it is
not an easy operation for now as it was before. We need to investigate on the error-signal
and nail down the reason.

Notes:

• Initially the err-sig had a weird shape and a low SNR (~2), later it became for unknown reasons a proper
  PDH with still the same SNR.
• Attempts to lock the North cavity have been done anyway. Without driving the BBEOM 
  cavity stayied locked for half an hour. 
• The error signal was taken at the monitor of the TTFSS and at the FSS box on the table (out1 and out 2); they were similar