(This concludes WP #6644) 

Kyle

RGA scans were taken this morning followed by the spinning down of the Vertex, YBM and XBM MTPs (main turbo pumps), isolating the scroll fore line and stopping the scroll pumps, "burping" GV5 and GV7's gate annulus volumes into the adjacent ion-pumped annulus volumes and then opening GV5 and GV7.  

Note:  

GV5's gate separated without a fuss but approximately 3/4 of the way into its "open" stroke it came to a halt with a "clunk" confirmed by a stoppage of audible displaced air out of the electro-pneumatic selector manifold .  I assumed that it was at the mechanical stop but CDS was indicating a "yellow" field.  After a minute or so of contemplation, and on its own, it resumed stroking to the mechanical stop.  GV5 has always been worrisome but seems to be getting worse with use.  GV7 behaved weird as well in that the gate seemed to separate as usual and CDS transitioned to "yellow" but the adjacent vacuum pressures indicated no gate separation.  With additional increase in pneumatic air pressure the vacuum pressures finally responded but the displaced air out of the electro-pneumatic selector manifold was barely audible during the stroking.  Even with 55 psi applied, it took noticeably longer than normal for it to open.  This is consistent with the "dribble' of displaced air.  I did note that the red light showing which side of the piston the instrument-air was being applied to was not illuminated.  I don't know if this is a new problem or if the bulb has been burned out for a while????