LBT Q Engineering Review MCSC Mount Control System

26-Oct-2007LBT Q Engineering Review Highlights (Q3/2007) Identified source of azimuth encoder signal nulls Identified source of azimuth encoder signal nulls Azimuth encoder declared salvageable Azimuth encoder declared salvageable Elevation motor brushes inspected and one replaced due to heat damage Elevation motor brushes inspected and one replaced due to heat damage

26-Oct-2007LBT Q Engineering Review Open Issues Technical Technical Occasional unexplained elevation tracking errors Occasional unexplained elevation tracking errors ELFR motor winding damage from Q1/07. Brush failure suspected. ELFR motor winding damage from Q1/07. Brush failure suspected. Low azimuth and elevation acceleration Low azimuth and elevation acceleration Unexplained phase discrepancy between azimuth and elevation encoder signals Unexplained phase discrepancy between azimuth and elevation encoder signals Elevation brake capacity appears to be diminished to less than 206 kN*m Elevation brake capacity appears to be diminished to less than 206 kN*m Schedule Schedule None None Financial Financial Postponed ordering spare azimuth encoder tape on financial grounds Postponed ordering spare azimuth encoder tape on financial grounds Resource Resource MCS competing for resources mainly against rotator development effort MCS competing for resources mainly against rotator development effort Azimuth encoder progress in Q4/07 is contingent on progress made on issue #772. Azimuth encoder progress in Q4/07 is contingent on progress made on issue #772.

26-Oct-2007LBT Q Engineering Review Progress (Q3/2007) Planning From Q2 Review Planning From Q2 Review Elevation and azimuth motor brush inspected and if necessary replaced √ Elevation and azimuth motor brush inspected and if necessary replaced √ Order replacement azimuth encoder tape – postponed Q1/08 Order replacement azimuth encoder tape – postponed Q1/08 Azimuth encoder tests planned for Q4/07 – on scheduled Azimuth encoder tests planned for Q4/07 – on scheduled Tape installation expected in Q4/07 – canceled Tape installation expected in Q4/07 – canceled Additional Progress Additional Progress Damaged tape salvageable Damaged tape salvageable Identified source of azimuth encoder tape signal nulls Identified source of azimuth encoder tape signal nulls

26-Oct-2007LBT Q Engineering Review Planning (Q4/2007) Install azimuth main encoder read heads Install azimuth main encoder read heads Commission azimuth encoder Commission azimuth encoder Inspect/repair elevation brakes Inspect/repair elevation brakes Order azimuth encoder tape Q1/08 Order azimuth encoder tape Q1/08