After a power outage, some electronics refuse to turn back on unless I unplug the power brick completely on the electronic side. Why does this happen?
After a power outage, some electronics refuse to turn back on unless I unplug the power brick completely on the electronic side. Why does this happen?
I have some automated pet stuff in my house. There were 2 power outages 2 days in a row. After each one, the pet electronics refused to turn back on even if I unpluged and replugged the power brick from the wall outlet side. They would only turn on if I unplugged the power brick on the electronics side and plugged it back in.
This is kind of a pain because of the cat stuff we own is a litter robot and where it's placed is really tight. It's a huge hassle to access the back side of it to unplug the power brick.
So my question is, why does this happen and are there any workarounds so I don't need to unplug the power brick when it happens?
Some Systems go into a save mode when the Starting current is to high. Wich is usually what happens after a power outage.
Ist a safety feature so a lightningstrike doesn't grill the thing or start a fire from it or electrocute someone that is touching it.
It’s hard to tell without a circuitry layout, but my best guess is that there’s probably capacitors in the power brick acting as an electrical filtration for the motors to make them operate smoothly and reliably.
The capacitors are probably discharging some electricity that are keeping some circuit protective device alive. Unplugging the power brick is probably the only true way to completely remove electricity from the unit.
Oh that does make sense. So if I unplug the unit from the wall outlet side and just wait it should also work? In theory I just need to wait long enough for the power brick to discharge completely. I'll try that next time. Thank you!
It’s just a theory based off of my own experience, but if that’s the issue, it kinda depends on how large the capacitors are and what kind of capacity they’re capable of holding.
If it is the issue, I’d expect it to take like 5 minutes for it to discharge completely, but that’s just a guess. If everything is already out of its usual place, you could probably test it if you’re curious enough.
Could also be the exact opposite (experienced this with consumer grade electronics based on microcontrollers often enough):
Because of the large capacitors, voltage from the power brick kinda "ramps up" when it is plugged into the wall. The device/its MCU/most specifically its clock circuit however prefers a hard edge of power being turned on, to reliably trigger its power on reset circuit/oscillator.
You can think of it similar to a pendulum/newton's cradle/metronome - they also prefer one decisive push to get going reliably.
Unplugging the brick for a longer time is still worth a try, but it could also be this.
Excellent question. Any time my power goes out I know that i have to unplug my PC to get it to wake up