Alcator C-MOD Weekly Highlights January 28, 1997 Reassembly of Alcator C-Mod was delayed somewhat this week when the EF1L coil high voltage ringing test did not not meet specifications. Breakdown occurred between the coil terminal and one of the newly installed mounting plates. To fix this problem the mounting plate was removed, the coil insulation was repaired, and the edge of the mounting plate was machined back away from the coil terminal block. The repairs are complete, the coil has been rung successfully, and we will soon continue reassembly. All work on transmitter #1 switchgear is complete, and we are now making similar modifications to the switchgear for the #2 transmitter. Work on the crowbar system and triggers for the new transmitters continues as does fitup of the new coax. Coax runs have been layed out from the final, to the phase shifter and stub tuner, and then to the entrance to the cell. The required components are being fabricated at PPPL. All fault detection circuit boards for the new transmitters have been completed. Work on the power systems concentrated on new overvoltage protection boards for the EF4 supply. These boards use breakover diodes to detect overvoltages on the EF4 bus and trigger crowbar protection circuitry. The power systems group is also pushing forward with DNB installation. The new grounding system for the DNB is complete, specifications for the modulator/regulator are being generated, and the holding tank for oil used by the DNB supplies has been specified and is in fabrication. Upgrades to the glow discharge system are underway. The maximum resistance selectable under PLC control has been increased. This change will add some protection for invessel components during glow discharge conditioning. Hall current sensors have been added to the glow system so that the current to each glow electrode can be measured without regard to bias resistor selection. The fabrication of shutters for protecting the new tangential two-color interferometer (TTCI) mirror and the re-entrant window used by our wide angle camera is complete. Assembly of the the TTCI shutter is also complete and cycle tests should begin soon. Dave Terry was at U Texas last week discussing DNB issues. Earl Marmar attended the latest FESAC meeting in San Diego where discussions where held on the upcoming FESAC ITER review. Franco Porcelli of the University of Torino, Italy, just visited C-Mod. Dr. Porcelli is involved in a collaboration on sawtooth activity involving C-Mod staff and members of the PSFC theory group. He also presented an informal seminar "Comments on X-point Dynamics". Dave Johnson, Boris Grek, and Joe Bartolik from PPPL are at MIT this week working on the edge Thomson scattering system.