What is the reason for the message “A fault occurred with the external source” when using an AC Interface and OUT tests?
This message may occur if the test voltage is not achieved when an X- test program is run. This can be due to a fault with the external power source, AC Interface or the AT3600 itself (Please also see Thread No: 1541 for debugging the failure).
In addition, if OUT tests are being used, it is important to ensure that relays connected to the USER port do not conflict with voltages applied via the AC Interface and external power source.
Also, there is a fuse on the AC interface directly below the CT10-20 current transformer. Please check that this is not blown. This can also cause the error message above.