testing anomaly

testing anomaly
« on: May 24, 2018, 10:12:27 am »
Is there any way to print a config of the settings i currently am using so i can post it here to assure correctness of test settings, because i am not able to reproduce the same test twice. I am just testing one component on the board witch consist of 16 pins the IC is "ADG712BR" all I am trying to do reproduce the same test. to assure im setting a good reference but every time i scan the same 16pin ic over again it fails on different pins every time. Am i doing something wrong in my test or do i have the wrong setting in the workstation? also when adjusting the tolerance, If i go from 5 to 10 am i giving more room for error or less?

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Re: testing anomaly
« Reply #1 on: May 24, 2018, 10:30:24 am »
Welcome to the Huntron Users Support Forum!

It is difficult to tell what the issue might be without seeing signatures. The most common issue I see is a charging effect that changes the width of the semiconductor signatures slightly. This is especially true when testing at lower voltages where the horizontal scale of the signature (voltage) is small and easily affected by small charges held on the PCB from a previous scan. Try using the Drain feature set in the Ranges tab for the affected component Pins. If the differences are usually small also try setting a second Reference.
The most important troubleshooting tool is your eyes.

Re: testing anomaly
« Reply #2 on: May 24, 2018, 10:58:08 am »
Are you getting a clean trace on the pins you are testing?
As Curtis says charging on component pins would cause inconsistent results.
Try putting a delay in between tests to allow for this.
If you have a spurious trace, lots peaks and troughs rather than a clean diode junction capacitance trace, try altering the frequency you are using.

Re: testing anomaly
« Reply #3 on: May 25, 2018, 06:55:07 am »
Thankyou guys for the feedback I really appreciate all the help i can get. i did find that testing with a higher frequency does help and get me less jitters or jumps in the signature. is it normal for the signature to jump around when scanning a sequence using the manual probes and the foot pedal? all seems normal until i hit the foot pedal to confirm pin # or to move to next pin. and Curtis is there a way to print a config of my current settings on the workstation. to ensure proper use.
Again I thank you for any and all input

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Re: testing anomaly
« Reply #4 on: May 30, 2018, 07:08:21 am »
Some CMOS components are inherently unstable when tested with an external oscillating signal. I don't think it necessarily has much to do with using a foot pedal. It is just that the signatures are captured at two different times. There is an old application note on the Huntron web site that discusses signature repeatability:
http://www.huntron.com/sales-support/pdf/prob_x.pdf
Much of this app note deals with old hardware so you need to take the information and apply it to todays techniques (i.e. it talks about using "Merge" but today we usually deal with multiple References). The part where it talks about adding resistance between voltage and ground may help.

Regarding printing test configurations, try creating a Tree report (View menu/Reports/Tree) and select the Detail Level as Range. Once the report is created go to the File menu/Export Document where you could export the information to a Excel format (XLS) and then use Excel to isolate the information you need.
The most important troubleshooting tool is your eyes.

Re: testing anomaly
« Reply #5 on: November 16, 2018, 04:12:43 am »
Is there a particular reason why the Detail Level needs to be set as Range?