Dear support team,
I have N5181A with problems on A3 unit. Once I have faced with Open loop and VCO test error. I spent hours in troubleshooting and checking, drawing on circuit diagram of VCO A3 unit (attached). I have found that if I remove resistor 4221 the VCO syntezer test successfully passed. But phase control loop test (next one) of corse not.
To be honest I do not completely understand how this part works and, as a result I can not find the root case of fault.
Could you help me with understanding or give me some advices about repair?
Hello Integrator,
From the screen grab, it looks like there is something wrong with the PLL. We cannot discuss the schematics in more detail because they are IP.
Contact Keysight Extended Support and they can provide more options for you to fix your N5181A:
Contact: N5181A MXG RF Analog Signal Generator, 100 kHz to 6 GHz [Discontinued]/United States | Keysight
If you wish to speak with someone on the phone, call the toll-free number: 1 (800) 829-4444 Press #, then 2
Thanks,
Jonathan