Bad Cable or bad test fixture ?

A common testing problem is determining whether a reported failure is truly a problem with the Device-Under-Test or a problem with the test interface. Test connectors wear out with repeated usage, pins break, plating is worn off and intermittent readings can occur. Any defects in the test interface will look like defects in the Device-Under-Test. The bottom line? You need a way to ensure your test fix Turing is 'Error Free!'

How do you ensure that your test fixturing is working properly no matter what type of fix Turing you use?
Shorting plug made by soldering all pins together on connector.
Click for view of Soldered pins on connector


BUILD YOUR OWN TEST BLOCKS!

Whether you use adapter cards or adapter cables, if you implement an 'adapter verification process' you'll be assured that you are testing with good adapters.

• Step #1: Make a Shorting Test Block for each adapter you test cables with.
  How do I make a Test Block? Solder all the pins together on a mating connector of the connector on your adapter. (You can short all the pins together or, if more convenient, any pattern of connections - but it is necessary to include every pin in the connector).
   

• Step #2: Learn and verify each TEST BLOCK. Because the Test Block has interconnections, it will have its own Signature when it is "learned" by the tester. Verify that every point on the Test Block is included in the wire list. Use the Cirris tester to print out the "wire list" then verify it just as you would a learned cable. (Remember that the location of the adapter on the tester is also important. When verifing an adapter it must always be in the same position on the tester.)
   

• Step #3: Label each TEST BLOCK. When you are confident that your test block is correctly verified and all pins are included then LABEL the test block with the KNOWN GOOD Signature.
   

Test Blocks may be created using the connector only, or the connector with a short piece of cable attached. (Suggestion- when you have a "bad cable" cut the connectors off leaving a short piece of the cable attached. Use these to create shorting test blocks)
 

• Step #4: TEST your adapter!
  To test your adapters simply plug on your Test Block and learn. The signature should match the attached label. Unplug the Test Block and when the tester says 'Ready to Test' plug it back on. Use the Continuous Test mode to check for intermittent problems. Grasp the Test Block and move it from side to side. If you cause a failure to occur the adapter is probably worn out, dirty or may have wire trimmings in the connector shorting pins out. Whenever you suspect your adapter is no longer working properly, plug on your SHORTING TEST BLOCK and check it out

Whatever test interfacing scheme you use to test your cables, backplanes, harnesses, PC boards or what-have-you, it is usually fairly easy to make a test block out of a mating connector to test the interfacing you are using.

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