[ianhowson]

Irrelevant.

1. Downstream of the mains power supply are DC-DC converters that run the router hardware. Those contain the filters and capacitance you think you're fixing. Nothing in that router actually cares about mains power quality. They absolutely do not care about perfect sinusoids.

2. If you were seeing insufficient power to the router, you would observe crashes and faults -- not slowdowns.

3. Two different routers showed the same behavior, which suggests that the fault lies outside the router+power supply and more to do with something common (e.g. network, laptop).

The dip shows a reduction in voltage, and a larger one than I would like, but without a scale on either time or voltage, it's difficult to guess if it actually matters. I would suspect not, since the device does boot successfully. Again, the voltage doesn't matter, since the router runs off its internal DC-DC supplies, not the external power supply.

I'm happy that the capacitor and new supply has fixed the issue, but I'm unconvinced by the explanation. Check grounding between inverter and laptop.

[Panzer04]

Generic issues like brownouts and crashes I can believe as a power fault. Slowdowns? Not likely.

Possibly he's not describing the problems right. I can certainly believe a shitty enough power supply would cause problems.

[mindslight]

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.

[CoffeeOnWrite]

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.

[photon_rancher]

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

[wtallis]

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

[pinkorchid]

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...

[Waterluvian]

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

[PaulDavisThe1st]

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.

[jen729w]

My neighbour's internet was terrible last year. He replaced a bunch of stuff, and went as far as switching ISPs to my recommended provider. Nothing worked.

Finally a savvy helpdesk person had him move his ADSL router. I believe he moved it off a cheap power board and plugged it directly in to the wall.

All problems immediately solved.

[e28eta]

If it’s being moved inside the house, it could also have been a different phone jack that made the difference, or a different cable connecting to the jack.

[jen729w]

It wasn't that. It was the power board.

[PaulHoule]

ADSL is particular sensitive to electronic noise. I'm afraid to set up my HF ham radio again.

[gazchop]

I agree that you'd probably see crashes but it still could be power supply related. Crappy SMPS designs do tend to shovel some noise from the primary into the secondary side as well as adding their own. And there's a lot of noise generally coming from an inverter as specified. It might just be adding noise to the line and crapping on the SnR occasionally. ADSL is quite robust but with noise it does slow down horribly if you bend it hard. I used to be able to slow my line down keying on my amateur radio transmitter back in the day.

About the best thing they did was adding a choke on it.

On top of that, it's a crappy 40MHz analogue scope. You're not going to see anything useful.

[kllrnohj]

A fancy modern turbo'ing CPU which has power availability feedback loops might just slow down in this scenario, but I don't think anyone has put anything remotely that fancy into a low power SoC that these routers were using.

So yeah, seems unlikely the only impact would be a sluggish dashboard. Maybe the device was churning on error re-transmissions from the brownout? Like the CPU itself was OK but the ethernet ports weren't?

[ianhowson]

> Maybe the device was churning on error re-transmissions from the brownout

I think this is more likely. Two different routers impacted. Crappy grounding or induced noise causing high BER on the links.

[outworlder]

How fancy do we really have to get? A Raspberry Pi can detect an inadequate power supply and slow down.

Granted, cheap consumer devices are much simpler than that, but it's still something that can be added to the SoC.

[dustyventure]

I think the original Broadcom chips were overstock in the normal market because they were somewhat a nuisance of unnecessary checkboxes that would reward you with further testing/diagnostic complications in return for paying too much..

[KennyBlanken]

They were overstock because they were underpowered, overpriced garbage targeting the set-top market and those manufacturers weren't interested.

Ebon Upton started Raspberry Pi to help Qualcomm dump stock they couldn't get rid of otherwise.

Look at every single Pi to come out - it's been faster than what came before it, but in a matter of weeks half a dozen competitors have better boards with faster processors for cheaper - that don't have all the nonsense like RPi foundation repeatedly fucking up the power supply so vendors could milk people on "pi compatible" USB power bricks.

A Pi 5 16GB costs $120. Plus case ($10) plus power supply ($12) plus video adapter ($10)...$152. That is absurd.

[kllrnohj]

A huge chunk of the value of an RPI is the ecosystem & support. The actual hardware in & of itself is consistently mediocre to poor for the price these days.

I think RPI is starting to lose sight of that with the Pi 5 and especially the 16gb models. It's starting to just be expensive and the better support for an ARM SBC starts losing a lot of value when it's butting up against x86 mini-pcs like the large number of N100-based options at around the $150 price point[1]. They aren't really any less efficient, and x86 software support is still consistently better than ARM software support.

1: eg https://www.amazon.com/Beelink-Intel-N100-Computer-Desktop-D... - $170 for a complete unit w/ 16GB RAM & 500GB SSD.

[dustyventure]

It's funny that people were once proud of the pragmatic origin story and now apparently ashamed.

[undersuit]

Cool, I was going to research what a 16GB ram OrangePi would cost but their website is down for me.