Page History

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We left the cooling running, and the MPOD off.

1/21/2015

The poorly crimped pin (pin 20) on pigtail P4 corresponding to DVDD+ sense was repaired by Danh Du.  Shortly after, FEB L5b was powered on and the previously observed power issues (sense voltage = 0 and terminal voltage maxed out) were no longer present.

The SVT box was opened up and the high speed cables connected to L4t and L4b were re-seated.  Once this was done, a control link was established with FEB L4t and L4b. 

It was noticed that the current drawn by DVDD on FEB L6b (FEB 15) was lower than expected.  After probing the board, it was determined that the A+2.9V_DVDD regulator circuit had blown up.  The FEB support plate was then removed from the SVT box and the troublesome FEB was replaced by FEB 13.  Once the FEB support plate was reinserted into the SVT box, FEB L6b was powered on and everything looked as expected.

After reconnecting all of the high speed cables and power, all mounted FEB's were powered on and the control links on all of the were checked.  This check took place after the new firmware which allowed the control DPM to receive all 12 links had been loaded.  The test showed that all FEB's had control links, however, the control link associated with FEB L6b had several errors.  This is a previously known problem that can be fixed by switching FEB L6b to another flange channel.  The data links also looked fine. 

Once all FEB's were verified to work, the SVT box was sealed up, the FEB support plate cooling was connected and the chillers were turned on.  The cooling was left on and power was left off for the night.

Equipment

Interlock board

see Group C interlock board for instructions on monitoring and controls.

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