[HELP] Digital Sidecar troubles

[s1900ahon]

Originally Posted by CalTran

Huh. That's an interesting theory.

But it doesn't explain the whine you hear. I didn't read that part when I was looking at the post originally. I provided the note about the bent pins just because I don't typically see it when this kind of thread pops up. And I know it happens because I've seen it multiple times.

Now, for the whine. Is it high pitched or low? It is either the sound made by the constant tripping of a circuit breaker or an audible harmonic emitted by one of the switch-mode power supplies in the PDB (5, 12, or 24V). Also note that the sidecar and the analog breakout also have switch-mode supplies in them too, so be sure that the noise isn't coming from a sidecar next to the PDB and you're just assuming it is the PDB.

The sound of a circuit breaker constantly tripping will (in my experience) makes a lower pitched noise.

The sound of the switch-mode supplies will be higher pitched and may change frequencies based on the current being drawn. This may be caused by the most popular robot construction sin -- metal debris in the electronics.

To isolate whether it is the switch-mode supplies rather than a circuit breaker, you can remove all circuit breakers to see if it is the PDB, and then start adding one back at a time as others have suggested.

Since the failure didn't go away after changing sidecars, I doubt that the sidecar is the issue. And I doubt that it is a bent pin since I can't think how the loss of connectivity would generate a whine.