Troubleshooting: Fiber Optics

Note: These are internal instructions for MEG Core Staff. If you are not MEG Core staff, you are welcome to educate yourself, but please do not attempt without supervision or direct instruction.

Introduction to Layout

The fiber optic cables transmit timing and location data back to the electronics rack. Therefore there are two connection points:

1. The headbox in the MSR
2. The electronics rack (or affectionately, just "the rack")

The headbox is often the source of the issues, as it is interacted with more frequently than the rack. However, if you have already confirmed that the fiber optic cables have been reseated properly and data is still being lost after rebooting the rack, check the connection at the rack.

Instructions for Reseating Cables

First, ping eeg from the ACQ computer to confirm data is not being fully transmitted. If packets are being lost:

1. Extend the cable tray.
2. Optional: remove the cable and polish the ends, however this is not necessary on a frequent basis.
3. Firmly but gently reinsert the cable fully and reinsert the cable tray, ensuring the cable is firmly seated and the cable tray is locked in. There are two data cables, so be sure to insert the left cable back into the left slot and the right cable into the right slot. They are currently unlabeled, but the left one has a bit of tape on it.

Note: The blue light next to the fiber optic cable will be illuminated if it is connected correctly.

• 

  Headbox Connection
  (Inserted Fully)
  

• 

  Headbox Connection
  (Tray Extended)
  

• 

  Clock FO cable connection
  (Note: Single cable)
  

• 

  Data FO cable connection
  (Note: Two cables, bundled)
  

Rebooting the Rack

1. Shut off the rack via the round black button in the top right corner of the rack.
2. Turn off the HLU power switch.
3. Turn on the rack and wait for the lights to stop flashing.
4. Turn the HLU power switch on.

• 

  Electronics rack power switch
  (upper right corner)
  

• 

  HLU power switch
  (rocker switch)
  

Then, ping eeg again to confirm success. Repeat the reseating procedure as needed. As noted above, if you are confident with the connection in the MSR, check the connection at the box.