---+ SQUID controller board 132 failure

EBEX Palestine run 2011

Symptoms

• The FPGA would not respond (impossible to turn the board on).

Investigation

• A corner of the DB37 connector looks burned :
• The current draw on the +6V of the DfMUX would increase by 0.7A (at 5.7V) when the SQUID contrller board woulb be powered up.
• The +5V regulator would have +4.6V at its input and +4.5V at its output.
• The -5V regulator would have -5.7V at its input and -5.0V at its output.
• The chip U14 was super hot.

Fix

• Adam changed the chip U14 on 2011/07/25.

Comments

• The boards is now working fine.
• A similar problem where the FPGA is not responding after a SQUID controller has been running for a long time might be associated with it. The FPGA stops responding at one point. Then, after reboot of the DfMUX, the SQUID controller works fine again either right away or after some time.
• The U14 chip (DS90LV028ATM) may stop working when reaching a certain temperature.
• The possibly related problem above has only been seen in EBEX. Maybe the cabling is to blame since this problem has not been reported in any other experiment and the DB25 cables are only custom made for EBEX (other experiements use off the shelf cables).

-- FrancoisAubin - 2011-07-25

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This topic: AnalogFMux > WebHome > SquidControllerCommissioning > SqCtrl132Failure Topic revision: r1 - 2011-07-25 - FrancoisAubin

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