Alright, slackers. It's time for some good-ole jerry-rigged ghetto mod.
Had this router(Archer C80) laying around for a few months, just gathering dust and doing nothing.
During the early blackouts one of my customers tried to wire it to a battery on his own, but same as usual: either dropped something or got a phone call, and after getting back to business - reversed polarity on the cable. End result - big-ass hole on the input side, few blown caps, and non-working low voltage rails. He bought a new one and gave this one to me for parts in exchange for a proper battery cable with DC-DC stabilizing module(buck-boost).
My main router at the office is very old and nearly dead (cheap-ass DIR-300 running DDWRT for the past decade or so), and in dire need of replacement. So, I dived into the rabbit hole of fixing this pile of ash and magic smoke.
First, I drilled off the burnt part of the PCB to remove an internal short. What's worse, is that I had to desolder that flimsy switch, a power jack, and half of the 12V side to do so.
Second, I attempted to revive both 1.8V and 1.2V rails. PWM controller on 1.2V was dead, while the other one ended up being alive. Didn't find a replacement or an equivalent (google couldn't even find a picture by markings, let alone a proper datasheet), so I've decided to use what I had laying around.
Tried generic LDOs, hoping that the load is low enough, but no luck. During a startup sequence the load on both rails is so high, that a puny AMS1117 goes to thermal shutdown almost immediately.
So, I swapped the IC to the smaller rail and did another ghetto-mod within a ghetto-mod.
Had a pack of mini560 modules in a 3.3V config. I occasionally swap the feedback resistor to make it a 5V module, but this time I've decided to go the other way around. there is no datasheet, but most sellers list a chart with feedback resistor values for 3.3V/5V/9V/12V. So, I interpolated it to my desired ~1.8V by stacking two stock 4.7k resistors on top of each other. Resulting voltage was 1.89, which is a bit high, but better than nothing.
Removed some unused thing, soldered 3 wires, fixed it all with some hot glue, and started testing.
Router came back to life immediately. Nothing exploded, nothing overheated. Did a quick reset, tested for a full work day and so far not a single issue.
I think I will add a little rad and a 5V fan to keep SoC cool, but that's a ghetto-mod for another day.
