R350 - Power Supply in Overvoltage Protection
Date: May 97
Revision: B.02.xx
The "R350 - Power supply in overvoltage protection" error is generated because the system is detecting a discrepancy between the sense and the source voltages at the board under test.
R350 troubleshooting suggestions:
Is your power supply wiring correct?
Check for probes not making contact, stuck probes, etc.
Check for power sense and supply miswiring. Use the fixture/trace file to find the power sense and supply probing locations.
Another test to check your power supply sense wiring: expose the power probes and directly jumper the high side of the supply to the high sense probe and the low side of the supply to the low sense probe. Now, run the test without the fixture.
If you no longer see the R350 error, this indicates that the sense is not correctly detecting the power supply voltage when you are running your fixture.
Check the traces on your board. Do the same test described in the previous paragraph, but run the test with the board and fixture on the testhead. If you no longer see the R350 error, this indicates that there may be a bad trace on the board or your board description is incorrect.
Is your device under test (DUT) power supply bad?
If you are experiencing the R350 error on multiple testheads with the same fixture and board, this is probably not the case.
To check your DUT power supplies:
Turn on the DUT power supplies.
Directly on the back of the power supplies, measure the voltage from signal high to signal low using a voltmeter.
Measure the voltage from sense high to sense low using a voltmeter.
These two measured values (for each supply) need to be identical (within a certain marginal error that is set for overvoltage for each supply. Check your power supply manual for the exact value). If the measured values are not identical for one (or more) of your supplies, this points to a power supply that may be faulty. If you find this to be the case, you can further verify the integrity of the power supplies by running full hardware diagnostics on your system.
Is the topology of your board affecting the order in which the power supplies are brought up?
We have seen the R350 in situations where it was a case of order sensitivity based on the topology of the board. Setting up the power supplies in the opposite order or using the "wait" option on the "sps" command ensures that the supplies come up in the order that you need them to.
Is the correct board on the fixture?
The R350 can be generated when you have the incorrect board on the fixture.
If utilizing parallel power supplies, are they set up correctly?
For the recommended procedure on setting up parallel power supplies, reference the Agilent 3070 SeriesII Users' Manual: Test & Fixture Development - Connecting DUT Supplies in Parallel.
Are your power supplies set-up to provide the power your board requires?
Check to make sure the voltage and current your board requires was correctly described to the system so enough probes are assigned. |
