New source tray was installed on TM4 yesterday. LD was used to pump down all water lines. Tube heater +D circuit has a big leak  around water block area. At base LR5.5 XE-5 atm.cc/sec, base pressure 170 mtorr, When Chad  moved this helium probe close to  water block area, The leak rate on LD went to maximum level right away. When the probe was moved out of water block area, the LR went back to base level. The test repeated again with same result. Also, Before helium spray test, I applied 80 psi air into the circuit. The air pressure can not be held in the circuit. The pressure drop on the line is quick. This shows a big leak on  D line as well. The rest water lines are fine. I pumped all of them down to LD bottom scale without problem. Chad and I helium sprayed window and MSP water blocks. No leak has been found.  The only line we have problem is the D line.

D line is still leak after repair and installation. We suspected the c-seals issue on this module. So, all water lines have been sprayed with helium for leak check.  Found "B" line target oven negative  is also leak. The rest line are good on helium spray leak check.  The further investigate on thi issue is taken place now.