Yeah, I've lost two modem/routers to power outage incidents, despite them being on a reasonable quality surge protector.

But that was an all-or-nothing failure mode in which they would power up but never do anything else. Performance changes is a claim that requires much stronger evidence.

When I hooked a Raspberry Pi (model B maybe?) up to an analog input on my Marantz NR1605, the UI of the receiver got noticeably laggier until it was barely responsive. Disconnecting made the UI perk back up. I noticed the Pi had a 2.5V DC bias on its audio out. I didn't investigate further.

As for the article, I'm left with more questions. Surely the solar inverter wasn't running all the time in series, like a double conversion UPS, right? So how how would the mains waveform have been significantly affected in normal operation?

Also those scope traces, what's the scale? Are we talking 100mV dip, or a 1V dip? And is that a storage scope, or is that one cycle of the supply's ongoing ripple? And the complete lack of any dip on the "fixed" trace with extra capacitance makes me wonder if they even got the triggering right.

I think the inverter is always running in between the batteries and the AC outlets. It's a dedicated "solar circuit".

I have questions. What's the point of a dedicated solar circuit? They are leasing from their "local lines company". If the lines company is in the leasing business, this system must be grid-tied right? Why the dedicated solar circuit?

Also, is it common for full sine wave inverters to produce power less clean than the grid? Maybe when the batteries are low? Curious.

I’m super fascinated by the rare occasion that digital things degrade in an analog fashion. Usually they just work or don’t.

That actually happened at my job a few years ago, where some extra power draw off a power supply that was also feeding a PC would slow down the code running there. It does sound crazy...

There’s oscillators out there that slowdown as they brownout. That would cause those symptoms. A lot of logic families have slower edges and longer delays too, not that there would be much asynchronous logic in a router.

Could also be affecting the analog circuitry more if the droop is too bad or its browning out. That could be loss of gain, SNR, etc.. that could cause packet loss and retransmissions

Are any of those oscillators running off mains power rather than off a lower, separately-regulated supply?