microphonics inductors
It's a nightmare.
On the bench everithing is working perfectly, You installa your PCB inside the box and mount it on your machine and nothing works !
Manly is due to the change of capacity between the walls of the box and the resonating elements of the PCB ( oscillators, tuned circuits, ecc ).
Vibrating the distance between the PCB and the cover change and then change also the capacitance between the two elements.
Solutions are to use THICK walls, use many screws to lock your PCB inside the box, avoid ( if possible ) to think to unscreened narrow band filters and use the filter for the PLL with the highest frequency.
Often is a cut and try work.
Mandi