The bad news...

• We were curious on actual actuation signal being sent to EOM by the TTFSS boxes.
• So we opened the north path and hooked up clips to TP4 in D090183. This point is used for PCMON signal.
• We found that there is a strong ~5V spike happening at this point at a rate of 60 Hz.
• This spike rails the EOM and hands of the error correction to pzt which happens slower.
• But when we increase the common gain in our circuit, this spike makes everything unstable at a much smaller gain then what we want to use.
• This is clearly a leak from AC supply, from where and how is unknown at the moment.

The good news...

• We got something to work at and hopefully this is our culprit.
• If we get to remove this and increase our common gains high in FSS, we might get a deeper look in the noise.

Steps ahead:

☐ Reroute AC power cables separate from signal cables.

☐ Add chokes or loop cables around ferrite cores to increase impedance to ground loop current.

☐ Shield the FSS 37 wires cable with aluminium foil.

☐ Add a thick grouning from table to rack.

☐ Grounding all DC supplies to a single point in a star configuration with thick metal/wire.

☐ Check all DC power supplies if they are leaking these 60 Hz spikes.

☐ Removing the AC power strips from the table sides. Connect the camera power cables far way from table top.