E5071c netwok analyzer problem

[yuchungchen]

Hello,
I got a problem of "phase lock loop unlocked in e5071c.
Which board may be broken?
Anybody can help me. Thanks

[DaJMasta]

It's not going to be solvable with basic information or explanation over text, but a starting point would be to thoroughly test the symptoms it shows.  Does it show with partial spans?  Lower RBWs?  If you feed in a signal does it appear at the right frequency?  Right level?  With extra harmonics?  With normal looking sidebands?

I'd take a look at the manual for the block diagram of the unit, any info on what board is what internally, and if they have a more detailed description of the error message you're getting.  Also worth running a more comprehensive self test if one is available - I know the A models had a vba script that would give you some additional board level test info.

A unlocked PLL could be an issue with one of its parts, the VCO, the power supply, the main timebase, any of the amplifiers in that chain, a frequency doubler, a cable - any number of things.  More detailed testing may start to point you in a clearer direction, and then it's time to crack it open and start measuring.