Damaged resistor network in SCXI-1303 w/1102C

[jamiestewart]

While using a Fluke 724 Temperature Calibrator to check calibration of temperature inputs on an SCXI-1303/1102C I blew the Fluke's internal 50mA fuse.  The SCXI-1303 temp inputs were configured 10ohm bias resistors and no pullup resistors.  All TC measurements were correct however after the test I removed the bias resistors and found that one leg was reading ~515ohm.  The Fluke common output was accidently referenced to ground during the procedure.  The SCXI-1303 manual warns not to use ground referenced signals when only bais resistors are installed.  Has anyone experienced this issue? 

[Brian F.]

Hello Jamie. 

I checked the 1303 manual and saw what you are talking about.  The manual says "Connecting an external ground-referenced signal with the 10 ohm bias resistor network in place can cause permanent damage to the resistor network and the traces on the SCXI-1303 printed circuit board."  It appears that this is exactly what happened and your board is probably damaged accordingly.  I would recommend contacting National Instruments to get this board repaired.  This can be done by following the procedure outlined at:

Sending a National Instruments Board in for Repair or Calibration

http://digital.ni.com/public.nsf/allkb/5B6448ED65EA711186256A3700800C67

Have a great day and feel free to give us a call when you wish to return your card!

Brian F
Applications Engineer
National Instruments