The following North Hot Cell work was completed over the last week under work permit I2018-12-12-1:

Thurs Dec 13^th:

• Prepared master side according to removal manual (noticed screwing in the right side locking screw was not as smooth to go in as normal; left side was smooth like normal)
• Removed manipulator roof block and set down in yellow frame (required some stacked wood to prevent light from bottoming out)
• Removed steel side plates in NHC manipulator hatch
• Removed the slave end (SN: 9764) – noticed “Right Elevation/Twist Coupler” off of vertical by around 30 degrees
• Wrist elevation of removed slave end was not locked, lifted it slightly and this brought the coupler to the vertical position and it locked with a click
• Suspected the thru-tube also would be misaligned, confirmed by inspecting visually in hot cell (Unsure why this misalignment occurred considering we followed the removal procedure properly.  One theory is that when we accidentally left the timing screw in the master side handle cable drum last time it may have caused things to get a little out of alignment)

Friday Dec 14^th:

• Un-did the right side locking screw on the master
• Then could turn coupler on the thru-tube to the vertical position from within the hot cell
• Re-locked the right side locking screw (this time it went in smoothly)
• With all couplers on thru-tube vertical we then installed the replacement slave (SN: 9352) as per instructions
• For future slave end changes should use some sort of long chain or sling instead of having the auxiliary crane hook block within the hatch (some sort of T-hook type lift feature replacing the bail may work better as well)
• Evaluated the manipulator: seemed to be working normally, Chad tested plugged in LED lamp plug and also opened and closed the work table hatch
• Noticed Z motion tape on slave end loose when fully extended in Z (nice and tight when retracted) – this seems to be normal
• Confirmed manipulators can reach all surfaces of the table
• Then tested remote handling of LED light fixtures from the Target Hall using pole tools through the manipulator roof hatch
  • Started with both LED light plugs un-plugged
  • Used 9’ standard beam lines RH pole tool (this worked fine, but 10-12’ would be better)
  • Curved hook end attachment
  • First lifted cables out of all cable tray sections (the wall mounted Panduit)
  • Then removed the East light fixture assembly (IRH1800) - lifted from designated lift loop (IRH1796) – This went smoothly
  • Hoisted up into the Target Hall, then lowered back down to re-install
  • To reinstall had to hook the assembly at a lower point due to flex of the pole from the weight of the assembly (hooked just below the ballast for installation).  Using this method reinstalling the fixture went smoothly.  I will update the design to move the designated lift point (or add an additional one) at this location.
  • Once the light fixture was on the bracket, replaced the cables in the cable tray using the pole tool.  The final section on the east wall before the outlets was a little tricky, but by viewing and reaching from the north-west corner of the hatch it was do-able
  • Confirmed visually that remote removal and installation of the west fixture can be done using the same procedure as the east
• Replaced lamp block (stored lifting hardware for hatch side plates above block, below hatch cover)

Monday Dec 17^th:

• Left side slave-end boot was installed as per manual instructions.  It was done with two people inside the cell this time which went much smoother than just one last time (the boot was not installed on the slave prior to moving it into the hot cell because we wanted to inspect the tape and cables after installation and the boot would prevent that)
• The condition of both boots was checked. Both appear to be in new condition with no signs of degradation.  The material seems pliable and strong.
• Chad Fisher, ISAC Hot Cell Operator, checked the light level from the cold side of the hot cell and confirmed that it is acceptable.  However, without the operator level LED lighting it was too dim.

 Tuesday Dec 18^th:

• Lift bails for both manipulator slave ends set to farthest north position which results in face that mates with thru-tube to be close to vertical when hanging from lift bail
• Work table, stairs, entrance floor area, pre-filter assembly, tool port, window cover, and hot side service connection panel vacuumed and wet wiped to remove dirt and dust.
• NHC inlet damper (located in Target Hall) adjusted to set NHC depression to around 1.05”wc (the NHC damper is currently not responding to the NVCS and needs to be investigated and repaired by Controls Group and/or Mechanical Services)