Hi Chen,
It looks like you need to return the PXI-5600 for repair. Thank you for your patience troubleshooting this. When you speak to an RMA Coordinator at NI (1-800-IEEE-488), providing them with the information that PLL2 and PLL3 seem to be intermittent will help our repair techs complete the repair more quickly.
Regards,
Andy Hinde
National Instruments
