The leak check of the cold box diff pump fittings.  Found a leak at the 
base of the diff pump on the tee that is apparently used to fill the pump 
with oil.  The fitting was removed and a plug was removed that resembled a 
dip stick (approx 1" long).  Tbe dip stick was charred black as if it had 
been hot.  The seal between the dip stick and the tee was not an O-ring.  
It looked like a high temperature glue?  For leak checking purposes, an O-
ring was fitted to the dip stick and reinserted in situ.  Only the top 
portion of the tee was removed.  The lower cap was slathered in vacuum 
grease. Pumping back down was slow.  After two hours the vacuum was down 
to 2 torr.  At 6:30 pm, the vacuum was 200 mtorr, so I turned on the 
filament and tried again to leak check.  I was able to get the throttle 
valve open a little wider than previously, but we still had a big leak.  I 
checked at the tee and got a strong response, but I also checked at the 
diff pump connections and also got a response, albeit much less.  We may 
have to blank off the entire diff pump to isolate the cold box so that we 
can leak check the system.  Dimo said he will be able to help tomorrow.  
For now, I will leave the roughing pump on the cold box and isolte the 
leak detector.  See you tomorrow.  
P.S. I left a voice mail re: welding at TITAN 8:30 am/blankets/work 
permits/extractor.   cb