The USB MSA is alive

This contains the scottyspectrumanalyzer yahoo group backup
Post Reply
spyker49
Posts: 254
Joined: Sat Apr 28, 2018 3:29 pm

The USB MSA is alive

Post by spyker49 » Sun Mar 24, 2013 8:50 am

The MSA's USB controller is fully working !

Still lots of ADC calibration to do but I can see 20-100-500 MHz signals in the sweeps.



But more importantly for the group: I traced some self induced problems to a lack of FIRST grounding all equipment and all test equipment to a common ground and seperately covering equipment and USB cable removal.



My new tiny ACER PC (like most laptops) is run from an UNEARTHED power pack, so when you plug in the MSA USB cable to the PC this causes mains leakage transients between all the various grounded pieces and some unhappy behaviours.

Of course some other USB port peripheral might have been providing an "accidental" PC ground but you never suspect that when your busy unplugging and swapping USB port cables.



So I wired in a ground wire to the Tiny PC Case, it's serial port locking screw. Then I saw my MSA was runing from another newer UNEARTHED power pack.



Mea Culpa: FlashBack from a few years ago: I did write and warned the group about all of this.

My lame excuse is that the newer gear crept in bit by bit and the grounding everything together first rule was laying dormant in my aging brain. Regards len

Post Reply