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E8357A Phaselock Lost error

Question asked by RM45 on Jul 19, 2013
Latest reply on Jul 30, 2013 by RM45

I have a PHASELOCK LOST error.  I got the machine dead in the water and repaired the power supply; I am not sure if the error is related.  All supply voltages seem to be present (except the status of the 9VDC is schematics or Power Supply extender board available).

The UUT is OK from about 11 MHz to 205 MHz; everything else is noise.  I have about 0 dBm power out at port 1 at 2 GHz which, according to the documentation, indicates that the source is OK and that the problem is in the A11 Phaselock board.  I did a Operating System Recovery, problem still there.

The receiver test shows A, B, R1, and R2 uniformly down about 70 dB.  My firmware is A.07.50.67; I have tried earlier firmwares.

One thing that is strange: with a 6ms sweep rate, the UUT sweeps then hangs up for 6 seconds before starting a new sweep (the CPU seems to hang up during the delay).  The sweep rate is not affected by changing the BW or number of points.

Also, the serial bus test hangs up about 60 seconds into each test.  The serial bus test on the machine doesn't resemble the documentation SB test.  Any thoughts on that would be appreciated as well.

Thanks in advance for any insights,